Ludovic ROLAND

Blog technique sur mes expériences de développeur.

Android – ShareActionProvider : personnaliser l’intent en fonction de l’application sélectionnée

7 janvier 2014

Avant même de vous parler de ce premier ticket, je vous souhaite à tous et à toutes une excellente année 2014 ! En ce qui concerne ce blog, j’espère que cette nouvelle année sera riche en articles !

Dans ce tout premier article de l’année 2014, je vous propose de voir comment il est possible de personnaliser un intent en fonction de l’application sélectionnée par un utilisateur via le composant shareActionProvider.

Qu’est-ce que le shareActionProvider ?

Petit rappel pour ceux qui ignorent ce qu’est le shareActionProvider.

Il s’agit tout simplement d’un composant graphique que l’on peut placer dans l’actionBar de nos applications afin de faciliter le partage social d’un texte, d’une URL ou encore d’une photo. Ce composant présentent de nombreux avantages comme par exemple :

  • le composant scanne automatiquement les applications installées sur le téléphone capables de partager du contenu ;
  • le composant retient la dernière application sélectionnée par l’utilisateur afin de la mettre en avant pour les prochaines fois ;
  • le composant est extrêmement simple à mettre en place !

Si le shareActionProvider est largement utilisé par les développeurs d’applications, le composant est également intégré dans plusieurs applications installées nativement sur les terminaux comme par exemple l’application Galerie.

Voici d’ailleurs quelques captures d’écran de cette application afin que vous puissiez visualiser le composant. Dans chacune des captures d’écran suivantes, le composant shareActionProvider a été entouré en rouge.

## Mettre en place le shareActionProvider

Avant toute chose et pour mettre en avant l’intérêt de ce ticket, je vous propose de mettre en place un shareActionProvider «classique» dans un projet Android, mais avant ça, n’oubliez pas de mettre à jour vos outils de développement, et de télécharger notamment la dernière version du code source d’Android. Nous en aurons besoin dans la deuxième partie de cet article.

Création du projet Android

Débutez par créer un projet Android comme n’importe quel projet Android en prenant soin de créer une activité portant une actionBar.

Mise en place du shareActionProvider

Pour mettre en place le shareActionProvider, nous allons nous tourner vers la méthode onCreateOptionsMenu de notre activité. Commencez par la vider de tout contenu :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  return true;
}

La première étape consiste donc à créer notre fameux shareActionProvider :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  //Etape 1 : création du shareAction Provider
  final ShareActionProvider provider = new ShareActionProvider(this);

  return true;
}

La deuxième étape consiste à associer à notre provider l’intent que l’on souhaite partager. Dans le cadre de cet article, je vais tout simplement partager le texte «coucou».

A noter que l’intent prend comme action une ACTION_SEND, et que dans notre cas, elle de type «text/plain» :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  // Etape 1 : création du shareAction Provider
  final ShareActionProvider provider = new ShareActionProvider(this);

  // Etape 2 : création de l'intent
  final Intent intent = new Intent(Intent.ACTION_SEND).setType("text/plain").putExtra(Intent.EXTRA_TEXT, "coucou");
  provider.setShareIntent(intent);

  return true;
}

Si vous compilez votre projet maintenant, vous ne remarquerez strictement rien, et c’est tout à fait normal ! La troisième étape consiste à créer un MenuItem auquel nous allons donner notre shareActionProvider en tant qu’actionProvider :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  // Etape 1 : création du shareAction Provider
  final ShareActionProvider provider = new ShareActionProvider(this);

  // Etape 2 : création de l'intent
  final Intent intent = new Intent(Intent.ACTION_SEND).setType("text/plain").putExtra(Intent.EXTRA_TEXT, "coucou");
  provider.setShareIntent(intent);

  // Etape 3 : création du menuItem
  final MenuItem item = menu.add(Menu.NONE, Menu.NONE, Menu.NONE, "partager");
  item.setActionProvider(provider);
  item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);

  return true;
}

Si vous compilez, votre application doit normalement avoir le rendu suivant :

Les lacunes…

Malheureusement, à l’usage, on se rend vite compte que le shareActionProvider a quelques lacunes. Par exemple, s’il est possible de connaître le nom de l’application que l’utilisateur a choisi pour partager du contenu, il est impossible de modifier l’intent pour la personnaliser.

Pourquoi personnaliser l’intent ?

Chaque application étant «unique» dans son utilisation, vouloir personnaliser l’intent peut paraître très pertinent, par exemple, pour :

  • ajouter un objet dans le cadre d’un e-mail ;
  • limiter le contenu à partager à 140 caractères dans le cadre d’un client Twitter ;
  • etc.

Personnaliser l’intent du shareActionProvider

Détecter l’application utilisée pour le partage

Avant de rentrer dans le vif du sujet, nous allons voir ensemble comment il est possible de connaître l’application utilisée par l’utilisateur pour partager du contenu. Pour ce faire, nous allons utiliser un setOnShareTargetSelectedListener :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  // Etape 1 : création du shareAction Provider
  final ShareActionProvider provider = new ShareActionProvider(this);

  // Etape 2 : création de l'intent
  final Intent intent = new Intent(Intent.ACTION_SEND).setType("text/plain").putExtra(Intent.EXTRA_TEXT, "coucou");
  provider.setShareIntent(intent);

  // Etape 3 : création du menuItem
  final MenuItem item = menu.add(Menu.NONE, Menu.NONE, Menu.NONE, "partager");
  item.setActionProvider(provider);
  item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);

  // Connaître l'application de partage
  provider.setOnShareTargetSelectedListener(new OnShareTargetSelectedListener()
  {
    @Override
    public boolean onShareTargetSelected(ShareActionProvider source, Intent intent)
    {
      return false;
    }
  });

  return true;
}

Comme vous pouvez le constater, la seule méthode que nous devons surcharger est la méthode onShareTargetSelected. Cette méthode nous fournit, via l’un de ses paramètres, notre intent. C’est grâce à ce paramètre que nous allons pouvoir récupérer le nom de l’application utilisée pour partager le contenu. L’exemple ci-dessous affiche le nom de l’application dans un Toast :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  // Etape 1 : création du shareAction Provider
  final ShareActionProvider provider = new ShareActionProvider(this);

  // Etape 2 : création de l'intent
  final Intent intent = new Intent(Intent.ACTION_SEND).setType("text/plain").putExtra(Intent.EXTRA_TEXT, "coucou");
  provider.setShareIntent(intent);

  // Etape 3 : création du menuItem
  final MenuItem item = menu.add(Menu.NONE, Menu.NONE, Menu.NONE, "partager");
  item.setActionProvider(provider);
  item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);

  // Connaître l'application de partage
  provider.setOnShareTargetSelectedListener(new OnShareTargetSelectedListener()
  {
    @Override
    public boolean onShareTargetSelected(ShareActionProvider source, Intent intent)
    {
      // Récupération du nom de l'application
      final String appName = intent.getComponent().getPackageName();
      Toast.makeText(MainActivity.this, appName, Toast.LENGTH_SHORT).show();

      return false;
    }
  });

  return true;
}

Si vous essayez d’utiliser les différentes applications de votre téléphone, vous devriez voir s’afficher par exemple :

  • com.facebook.katana pour Facebook ;
  • com.google.android.apps.plus pour Google+ ;
  • com.twitter.android pour Twitter ;
  • com.google.android.gm pour Gmail ;
  • etc.

Puisque nous avons accès à l’intent, il est très tentant de la modifier dans cette méthode ! Mais si l’on s’attarde sur la documentation de la méthode onShareTargetSelected, on peut y lire les lignes suivantes :

Modifying the intent is not permitted and any changes to the latter will be ignored.

Autrement dit, toutes les modifications faites ici ne servent à rien…

Quelques classes à intégrer

Pour modifier l’intent, nous allons devoir récupérer quelques classes du code source Android afin de les modifier. Les 3 classes à récupérer sont :

  • ActivityChooserModel.java qui se trouve dans «C:\opt\android-sdk\sources\android-19\android\support\v7\internal\widget» ;
  • ActivityChooserView.java qui se trouve dans «C:\opt\android-sdk\sources\android-19\android\support\v7\internal\widget» ;
  • ShareActionProvider.java qui se trouve dans «C:\opt\android-sdk\sources\android-19\android\support\v7\widget» ;

Copiez ces classes dans le projet Android et renommez les en MyActivityChooserModel.java, MyActivityChooserView.java et MyShareActionProvider.java en prenant bien soin de mettre à jour les références.

Suprise ! Rien ne compile ! Ne vous inquiétez pas, nous allons reprendre les 3 fichiers et corriger les erreurs.

Intégration la bibliothèque android-support-v7

Afin de corriger un certain nombre d’imports n’arrivant pas à aboutir, nous allons importer la bibliothèque android-support-v7 dans notre projet. J’ai déjà expliqué comment faire dans cet article.

Le grand ménage

Normalement, ça ne compile toujours pas ! Il convient de mettre à jour les différentes références. En effet, il convient de changer tous les appels aux classes ActivityChooserModel.java, ActivityChooserView.java par des appels aux classes MyActivityChooserModel.java et MyActivityChooserView.java.

Après ces changements, le projets devrait compiler sans problème.

Mettons les mains dans le cambouis…

Nous allons maintenant modifier le code d’une ce ces classes afin d’être en mesure de modifier notre intent dans notre activité. Il faut regarder du côté de la méthode chooseActivity de notre classe MyActivityChooserModel.java. On peut notamment y voir les trois lignes suivantes :

// Do not allow the policy to change the intent.
Intent choiceIntentCopy = new Intent(choiceIntent);
final boolean handled = mActivityChoserModelPolicy.onChooseActivity(this, choiceIntentCopy);

Un copie de notre intent est donc faite, ainsi, dans notre activité, nous recevons une copie et non l’originale. Corrigeons ça !

Pour ce faire, remplacez les trois lignes de codes par les lignes suivantes :

// Do not allow the policy to change the intent.
// Intent choiceIntentCopy = new Intent(choiceIntent);
final boolean handled = mActivityChoserModelPolicy.onChooseActivity(this, choiceIntent);

Ce qui est fait est finalement très simple : je ne fais plus une copie et je passe dans le reste du worflow l’intent originale !

De retour dans notre activité

Nous allons maintenant remplacer le shareActionProvider que nous avions intégré par notre myShareActionProvider. Puisque nous utilisons un shareActionProvider issue de la bibliothèque de compatibilité, nous allons devoir utiliser les méthodes adéquates. Tout d’abord, notre activité doit maintenant hériter de la classe ActionBarActivity. Puis, notre méthode onCreateOptionsMenu devient la suivante :

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
  // Etape 1 : création du shareAction Provider
  final MyShareActionProvider provider = new MyShareActionProvider(this);

  // Etape 2 : création de l'intent
  final Intent intent = new Intent(Intent.ACTION_SEND).setType("text/plain").putExtra(Intent.EXTRA_TEXT, "coucou");
  provider.setShareIntent(intent);

  // Etape 3 : création du menuItem
  final MenuItem item = menu.add(Menu.NONE, Menu.NONE, Menu.NONE, "partager");
  MenuItemCompat.setActionProvider(item, provider);
  MenuItemCompat.setShowAsAction(item, MenuItemCompat.SHOW_AS_ACTION_ALWAYS);

  // Connaître l'application de partage
  provider.setOnShareTargetSelectedListener(new OnShareTargetSelectedListener()
  {
    @Override
    public boolean onShareTargetSelected(MyShareActionProvider source, Intent intent)
    {
      // Récupération du nom de l'application
      final String appName = intent.getComponent().getPackageName();
      Toast.makeText(MainActivity.this, appName, Toast.LENGTH_SHORT).show();

      return false;
    }
  });

  return true;
}

La dernière chose à faire est de modifier le thème de votre application qui doit maintenant avoir un thème «compat». Par exemple, utilisez les lignes suivantes dans votre fichier AndroidManifest.xml :

<application
  android:allowBackup="true"
  android:icon="@drawable/ic_launcher"
  android:label="@string/app_name"
  android:theme="@style/Theme.AppCompat.Light.DarkActionBar" >

  <activity
    android:name="fr.rolandl.blog.shareactionprovider.MainActivity"
    android:label="@string/app_name" >
    <intent-filter>
      <action android:name="android.intent.action.MAIN" />
      <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
  </activity>
</application>

Si vous compilez et testez, vous devriez normalement être iso avec le shareActionProvider que nous avions mis en place premièrement.

Modifier l’intent

Il est maintenant temps de modifier l’intent «pour de vrai» !

Tout se passe au niveau de notre onShareTargetSelectedListener et plus spécifiquement au niveau de la méthode onShareTargetSelected. Pour l’exemple voici le comportement que je vais mettre en place :

  • si l’application utilisée pour partager est Gmail, je vais changer le type de l’intent, y ajouter un objet et changer son contenu par «gmail» ;
  • si l’application utilisée pour partager est Keep, je vais changer le contenu par «keep».

C’est parti !

// Connaître l'application de partage
provider.setOnShareTargetSelectedListener(new OnShareTargetSelectedListener()
{
  @Override
  public boolean onShareTargetSelected(MyShareActionProvider source, Intent intent)
  {
    // Récupération du nom de l'application
    final String appName = intent.getComponent().getPackageName();

    if ("com.google.android.gm".equals(appName))
    {
      intent.setType("message/rfc822");
      intent.putExtra(Intent.EXTRA_SUBJECT, "Subject");
      intent.putExtra(Intent.EXTRA_TEXT, "gmail");
    }
    else if ("com.google.android.keep".equals(appName))
    {
      intent.putExtra(Intent.EXTRA_TEXT, "keep");
    }

    return false;
  }
});

Je vous laisse le soin de tester le bon fonctionnement !

Le code complet

Comme d’habitude, voici le code complet :

### Le fichier AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="fr.rolandl.blog.shareactionprovider"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.AppCompat.Light.DarkActionBar" >
        <activity
            android:name="fr.rolandl.blog.shareactionprovider.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Le fichier MainActivity.java

package fr.rolandl.blog.shareactionprovider;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.MenuItemCompat;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import fr.rolandl.blog.shareactionprovider.MyShareActionProvider.OnShareTargetSelectedListener;

public class MainActivity
    extends ActionBarActivity
{

  @Override
  protected void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu)
  {
    // Etape 1 : création du shareAction Provider
    final MyShareActionProvider provider = new MyShareActionProvider(this);

    // Etape 2 : création de l'intent
    final Intent intent = new Intent(Intent.ACTION_SEND).setType("text/plain").putExtra(Intent.EXTRA_TEXT, "coucou");
    provider.setShareIntent(intent);

    // Etape 3 : création du menuItem
    final MenuItem item = menu.add(Menu.NONE, Menu.NONE, Menu.NONE, "partager");
    MenuItemCompat.setActionProvider(item, provider);
    MenuItemCompat.setShowAsAction(item, MenuItemCompat.SHOW_AS_ACTION_ALWAYS);

    // Connaître l'application de partage
    provider.setOnShareTargetSelectedListener(new OnShareTargetSelectedListener()
    {
      @Override
      public boolean onShareTargetSelected(MyShareActionProvider source, Intent intent)
      {
        // Récupération du nom de l'application
        final String appName = intent.getComponent().getPackageName();

        if ("com.google.android.gm".equals(appName))
        {
          intent.setType("message/rfc822");
          intent.putExtra(Intent.EXTRA_SUBJECT, "Subject");
          intent.putExtra(Intent.EXTRA_TEXT, "gmail");
        }
        else if ("com.google.android.keep".equals(appName))
        {
          intent.putExtra(Intent.EXTRA_TEXT, "keep");
        }

        return false;
      }
    });

    return true;
  }
}

Le fichier MyActivityChooserModel.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package fr.rolandl.blog.shareactionprovider;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;

import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ResolveInfo;
import android.database.DataSetObservable;
import android.os.AsyncTask;
import android.os.Build;
import android.text.TextUtils;
import android.util.Log;
import android.util.Xml;

/**
 * <p>
 * This class represents a data model for choosing a component for handing a given {@link Intent}. The model is responsible for querying the system
 * for activities that can handle the given intent and order found activities based on historical data of previous choices. The historical data is
 * stored in an application private file. If a client does not want to have persistent choice history the file can be omitted, thus the activities
 * will be ordered based on historical usage for the current session.
 * <p>
 * </p>
 * For each backing history file there is a singleton instance of this class. Thus, several clients that specify the same history file will share the
 * same model. Note that if multiple clients are sharing the same model they should implement semantically equivalent functionality since setting the
 * model intent will change the found activities and they may be inconsistent with the functionality of some of the clients. For example, choosing a
 * share activity can be implemented by a single backing model and two different views for performing the selection. If however, one of the views is
 * used for sharing but the other for importing, for example, then each view should be backed by a separate model. </p>
 * <p>
 * The way clients interact with this class is as follows:
 * </p>
 * <p>
 * 
 * <pre>
 * <code>
 *  // Get a model and set it to a couple of clients with semantically similar function.
 *  ActivityChooserModel dataModel =
 *      ActivityChooserModel.get(context, "task_specific_history_file_name.xml");
 *
 *  ActivityChooserModelClient modelClient1 = getActivityChooserModelClient1();
 *  modelClient1.setActivityChooserModel(dataModel);
 *
 *  ActivityChooserModelClient modelClient2 = getActivityChooserModelClient2();
 *  modelClient2.setActivityChooserModel(dataModel);
 *
 *  // Set an intent to choose a an activity for.
 *  dataModel.setIntent(intent);
 * <pre>
 * <code>
 * </p>
 * <p>
 * <strong>Note:</strong> This class is thread safe.
 * </p>
 * 
 * @hide
 */
public class MyActivityChooserModel
    extends DataSetObservable
{

  /**
   * Client that utilizes an {@link MyActivityChooserModel}.
   */
  public interface ActivityChooserModelClient
  {

    /**
     * Sets the {@link MyActivityChooserModel}.
     * 
     * @param dataModel
     *          The model.
     */
    public void setActivityChooserModel(MyActivityChooserModel dataModel);
  }

  /**
   * Defines a sorter that is responsible for sorting the activities based on the provided historical choices and an intent.
   */
  public interface ActivitySorter
  {

    /**
     * Sorts the <code>activities</code> in descending order of relevance based on previous history and an intent.
     * 
     * @param intent
     *          The {@link Intent}.
     * @param activities
     *          Activities to be sorted.
     * @param historicalRecords
     *          Historical records.
     */
    // This cannot be done by a simple comparator since an Activity weight
    // is computed from history. Note that Activity implements Comparable.
    public void sort(Intent intent, List<ActivityResolveInfo> activities, List<HistoricalRecord> historicalRecords);
  }

  /**
   * Listener for choosing an activity.
   */
  public interface OnChooseActivityListener
  {

    /**
     * Called when an activity has been chosen. The client can decide whether an activity can be chosen and if so the caller of
     * {@link MyActivityChooserModel#chooseActivity(int)} will receive and {@link Intent} for launching it.
     * <p>
     * <strong>Note:</strong> Modifying the intent is not permitted and any changes to the latter will be ignored.
     * </p>
     * 
     * @param host
     *          The listener's host model.
     * @param intent
     *          The intent for launching the chosen activity.
     * @return Whether the intent is handled and should not be delivered to clients.
     * 
     * @see MyActivityChooserModel#chooseActivity(int)
     */
    public boolean onChooseActivity(MyActivityChooserModel host, Intent intent);
  }

  /**
   * Flag for selecting debug mode.
   */
  private static final boolean DEBUG = false;

  /**
   * Tag used for logging.
   */
  private static final String LOG_TAG = MyActivityChooserModel.class.getSimpleName();

  /**
   * The root tag in the history file.
   */
  private static final String TAG_HISTORICAL_RECORDS = "historical-records";

  /**
   * The tag for a record in the history file.
   */
  private static final String TAG_HISTORICAL_RECORD = "historical-record";

  /**
   * Attribute for the activity.
   */
  private static final String ATTRIBUTE_ACTIVITY = "activity";

  /**
   * Attribute for the choice time.
   */
  private static final String ATTRIBUTE_TIME = "time";

  /**
   * Attribute for the choice weight.
   */
  private static final String ATTRIBUTE_WEIGHT = "weight";

  /**
   * The default name of the choice history file.
   */
  public static final String DEFAULT_HISTORY_FILE_NAME = "activity_choser_model_history.xml";

  /**
   * The default maximal length of the choice history.
   */
  public static final int DEFAULT_HISTORY_MAX_LENGTH = 50;

  /**
   * The amount with which to inflate a chosen activity when set as default.
   */
  private static final int DEFAULT_ACTIVITY_INFLATION = 5;

  /**
   * Default weight for a choice record.
   */
  private static final float DEFAULT_HISTORICAL_RECORD_WEIGHT = 1.0f;

  /**
   * The extension of the history file.
   */
  private static final String HISTORY_FILE_EXTENSION = ".xml";

  /**
   * An invalid item index.
   */
  private static final int INVALID_INDEX = -1;

  /**
   * Lock to guard the model registry.
   */
  private static final Object sRegistryLock = new Object();

  /**
   * This the registry for data models.
   */
  private static final Map<String, MyActivityChooserModel> sDataModelRegistry = new HashMap<String, MyActivityChooserModel>();

  /**
   * Lock for synchronizing on this instance.
   */
  private final Object mInstanceLock = new Object();

  /**
   * List of activities that can handle the current intent.
   */
  private final List<ActivityResolveInfo> mActivities = new ArrayList<ActivityResolveInfo>();

  /**
   * List with historical choice records.
   */
  private final List<HistoricalRecord> mHistoricalRecords = new ArrayList<HistoricalRecord>();

  /**
   * Context for accessing resources.
   */
  private final Context mContext;

  /**
   * The name of the history file that backs this model.
   */
  private final String mHistoryFileName;

  /**
   * The intent for which a activity is being chosen.
   */
  private Intent mIntent;

  /**
   * The sorter for ordering activities based on intent and past choices.
   */
  private ActivitySorter mActivitySorter = new DefaultSorter();

  /**
   * The maximal length of the choice history.
   */
  private int mHistoryMaxSize = DEFAULT_HISTORY_MAX_LENGTH;

  /**
   * Flag whether choice history can be read. In general many clients can share the same data model and {@link #readHistoricalDataIfNeeded()} may be
   * called by arbitrary of them any number of times. Therefore, this class guarantees that the very first read succeeds and subsequent reads can be
   * performed only after a call to {@link #persistHistoricalDataIfNeeded()} followed by change of the share records.
   */
  private boolean mCanReadHistoricalData = true;

  /**
   * Flag whether the choice history was read. This is used to enforce that before calling {@link #persistHistoricalDataIfNeeded()} a call to
   * {@link #persistHistoricalDataIfNeeded()} has been made. This aims to avoid a scenario in which a choice history file exits, it is not read yet
   * and it is overwritten. Note that always all historical records are read in full and the file is rewritten. This is necessary since we need to
   * purge old records that are outside of the sliding window of past choices.
   */
  private boolean mReadShareHistoryCalled = false;

  /**
   * Flag whether the choice records have changed. In general many clients can share the same data model and {@link #persistHistoricalDataIfNeeded()}
   * may be called by arbitrary of them any number of times. Therefore, this class guarantees that choice history will be persisted only if it has
   * changed.
   */
  private boolean mHistoricalRecordsChanged = true;

  /**
   * Flag whether to reload the activities for the current intent.
   */
  private boolean mReloadActivities = false;

  /**
   * Policy for controlling how the model handles chosen activities.
   */
  private OnChooseActivityListener mActivityChoserModelPolicy;

  /**
   * Gets the data model backed by the contents of the provided file with historical data. Note that only one data model is backed by a given file,
   * thus multiple calls with the same file name will return the same model instance. If no such instance is present it is created.
   * <p>
   * <strong>Note:</strong> To use the default historical data file clients should explicitly pass as file name {@link #DEFAULT_HISTORY_FILE_NAME}. If
   * no persistence of the choice history is desired clients should pass <code>null</code> for the file name. In such case a new model is returned for
   * each invocation.
   * </p>
   * 
   * <p>
   * <strong>Always use difference historical data files for semantically different actions. For example, sharing is different from
   * importing.</strong>
   * </p>
   * 
   * @param context
   *          Context for loading resources.
   * @param historyFileName
   *          File name with choice history, <code>null</code> if the model should not be backed by a file. In this case the activities will be
   *          ordered only by data from the current session.
   * 
   * @return The model.
   */
  public static MyActivityChooserModel get(Context context, String historyFileName)
  {
    synchronized (sRegistryLock)
    {
      MyActivityChooserModel dataModel = sDataModelRegistry.get(historyFileName);
      if (dataModel == null)
      {
        dataModel = new MyActivityChooserModel(context, historyFileName);
        sDataModelRegistry.put(historyFileName, dataModel);
      }
      return dataModel;
    }
  }

  /**
   * Creates a new instance.
   * 
   * @param context
   *          Context for loading resources.
   * @param historyFileName
   *          The history XML file.
   */
  private MyActivityChooserModel(Context context, String historyFileName)
  {
    mContext = context.getApplicationContext();
    if (!TextUtils.isEmpty(historyFileName) && !historyFileName.endsWith(HISTORY_FILE_EXTENSION))
    {
      mHistoryFileName = historyFileName + HISTORY_FILE_EXTENSION;
    }
    else
    {
      mHistoryFileName = historyFileName;
    }
  }

  /**
   * Sets an intent for which to choose a activity.
   * <p>
   * <strong>Note:</strong> Clients must set only semantically similar intents for each data model.
   * <p>
   * 
   * @param intent
   *          The intent.
   */
  public void setIntent(Intent intent)
  {
    synchronized (mInstanceLock)
    {
      if (mIntent == intent)
      {
        return;
      }
      mIntent = intent;
      mReloadActivities = true;
      ensureConsistentState();
    }
  }

  /**
   * Gets the intent for which a activity is being chosen.
   * 
   * @return The intent.
   */
  public Intent getIntent()
  {
    synchronized (mInstanceLock)
    {
      return mIntent;
    }
  }

  /**
   * Gets the number of activities that can handle the intent.
   * 
   * @return The activity count.
   * 
   * @see #setIntent(Intent)
   */
  public int getActivityCount()
  {
    synchronized (mInstanceLock)
    {
      ensureConsistentState();
      return mActivities.size();
    }
  }

  /**
   * Gets an activity at a given index.
   * 
   * @return The activity.
   * 
   * @see ActivityResolveInfo
   * @see #setIntent(Intent)
   */
  public ResolveInfo getActivity(int index)
  {
    synchronized (mInstanceLock)
    {
      ensureConsistentState();
      return mActivities.get(index).resolveInfo;
    }
  }

  /**
   * Gets the index of a the given activity.
   * 
   * @param activity
   *          The activity index.
   * 
   * @return The index if found, -1 otherwise.
   */
  public int getActivityIndex(ResolveInfo activity)
  {
    synchronized (mInstanceLock)
    {
      ensureConsistentState();
      List<ActivityResolveInfo> activities = mActivities;
      final int activityCount = activities.size();
      for (int i = 0; i < activityCount; i++)
      {
        ActivityResolveInfo currentActivity = activities.get(i);
        if (currentActivity.resolveInfo == activity)
        {
          return i;
        }
      }
      return INVALID_INDEX;
    }
  }

  /**
   * Chooses a activity to handle the current intent. This will result in adding a historical record for that action and construct intent with its
   * component name set such that it can be immediately started by the client.
   * <p>
   * <strong>Note:</strong> By calling this method the client guarantees that the returned intent will be started. This intent is returned to the
   * client solely to let additional customization before the start.
   * </p>
   * 
   * @return An {@link Intent} for launching the activity or null if the policy has consumed the intent or there is not current intent set via
   *         {@link #setIntent(Intent)}.
   * 
   * @see HistoricalRecord
   * @see OnChooseActivityListener
   */
  public Intent chooseActivity(int index)
  {
    synchronized (mInstanceLock)
    {
      if (mIntent == null)
      {
        return null;
      }

      ensureConsistentState();

      ActivityResolveInfo chosenActivity = mActivities.get(index);

      ComponentName chosenName = new ComponentName(chosenActivity.resolveInfo.activityInfo.packageName, chosenActivity.resolveInfo.activityInfo.name);

      Intent choiceIntent = new Intent(mIntent);
      choiceIntent.setComponent(chosenName);

      if (mActivityChoserModelPolicy != null)
      {
        // Do not allow the policy to change the intent.
        // Intent choiceIntentCopy = new Intent(choiceIntent);
        final boolean handled = mActivityChoserModelPolicy.onChooseActivity(this, choiceIntent);
        if (handled)
        {
          return null;
        }
      }

      HistoricalRecord historicalRecord = new HistoricalRecord(chosenName, System.currentTimeMillis(), DEFAULT_HISTORICAL_RECORD_WEIGHT);
      addHisoricalRecord(historicalRecord);

      return choiceIntent;
    }
  }

  /**
   * Sets the listener for choosing an activity.
   * 
   * @param listener
   *          The listener.
   */
  public void setOnChooseActivityListener(OnChooseActivityListener listener)
  {
    synchronized (mInstanceLock)
    {
      mActivityChoserModelPolicy = listener;
    }
  }

  /**
   * Gets the default activity, The default activity is defined as the one with highest rank i.e. the first one in the list of activities that can
   * handle the intent.
   * 
   * @return The default activity, <code>null</code> id not activities.
   * 
   * @see #getActivity(int)
   */
  public ResolveInfo getDefaultActivity()
  {
    synchronized (mInstanceLock)
    {
      ensureConsistentState();
      if (!mActivities.isEmpty())
      {
        return mActivities.get(0).resolveInfo;
      }
    }
    return null;
  }

  /**
   * Sets the default activity. The default activity is set by adding a historical record with weight high enough that this activity will become the
   * highest ranked. Such a strategy guarantees that the default will eventually change if not used. Also the weight of the record for setting a
   * default is inflated with a constant amount to guarantee that it will stay as default for awhile.
   * 
   * @param index
   *          The index of the activity to set as default.
   */
  public void setDefaultActivity(int index)
  {
    synchronized (mInstanceLock)
    {
      ensureConsistentState();

      ActivityResolveInfo newDefaultActivity = mActivities.get(index);
      ActivityResolveInfo oldDefaultActivity = mActivities.get(0);

      final float weight;
      if (oldDefaultActivity != null)
      {
        // Add a record with weight enough to boost the chosen at the top.
        weight = oldDefaultActivity.weight - newDefaultActivity.weight + DEFAULT_ACTIVITY_INFLATION;
      }
      else
      {
        weight = DEFAULT_HISTORICAL_RECORD_WEIGHT;
      }

      ComponentName defaultName = new ComponentName(newDefaultActivity.resolveInfo.activityInfo.packageName, newDefaultActivity.resolveInfo.activityInfo.name);
      HistoricalRecord historicalRecord = new HistoricalRecord(defaultName, System.currentTimeMillis(), weight);
      addHisoricalRecord(historicalRecord);
    }
  }

  /**
   * Persists the history data to the backing file if the latter was provided. Calling this method before a call to
   * {@link #readHistoricalDataIfNeeded()} throws an exception. Calling this method more than one without choosing an activity has not effect.
   * 
   * @throws IllegalStateException
   *           If this method is called before a call to {@link #readHistoricalDataIfNeeded()}.
   */
  private void persistHistoricalDataIfNeeded()
  {
    if (!mReadShareHistoryCalled)
    {
      throw new IllegalStateException("No preceding call to #readHistoricalData");
    }
    if (!mHistoricalRecordsChanged)
    {
      return;
    }
    mHistoricalRecordsChanged = false;
    if (!TextUtils.isEmpty(mHistoryFileName))
    {
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
      {
        executePersistHistoryAsyncTaskSDK11();
      }
      else
      {
        executePersistHistoryAsyncTaskBase();
      }
    }
  }

  private void executePersistHistoryAsyncTaskBase()
  {
    new PersistHistoryAsyncTask().execute(new ArrayList<HistoricalRecord>(mHistoricalRecords), mHistoryFileName);
  }

  private void executePersistHistoryAsyncTaskSDK11()
  {
    new PersistHistoryAsyncTask().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, new ArrayList<HistoricalRecord>(mHistoricalRecords), mHistoryFileName);
  }

  /**
   * Sets the sorter for ordering activities based on historical data and an intent.
   * 
   * @param activitySorter
   *          The sorter.
   * 
   * @see ActivitySorter
   */
  public void setActivitySorter(ActivitySorter activitySorter)
  {
    synchronized (mInstanceLock)
    {
      if (mActivitySorter == activitySorter)
      {
        return;
      }
      mActivitySorter = activitySorter;
      if (sortActivitiesIfNeeded())
      {
        notifyChanged();
      }
    }
  }

  /**
   * Sets the maximal size of the historical data. Defaults to {@link #DEFAULT_HISTORY_MAX_LENGTH}
   * <p>
   * <strong>Note:</strong> Setting this property will immediately enforce the specified max history size by dropping enough old historical records to
   * enforce the desired size. Thus, any records that exceed the history size will be discarded and irreversibly lost.
   * </p>
   * 
   * @param historyMaxSize
   *          The max history size.
   */
  public void setHistoryMaxSize(int historyMaxSize)
  {
    synchronized (mInstanceLock)
    {
      if (mHistoryMaxSize == historyMaxSize)
      {
        return;
      }
      mHistoryMaxSize = historyMaxSize;
      pruneExcessiveHistoricalRecordsIfNeeded();
      if (sortActivitiesIfNeeded())
      {
        notifyChanged();
      }
    }
  }

  /**
   * Gets the history max size.
   * 
   * @return The history max size.
   */
  public int getHistoryMaxSize()
  {
    synchronized (mInstanceLock)
    {
      return mHistoryMaxSize;
    }
  }

  /**
   * Gets the history size.
   * 
   * @return The history size.
   */
  public int getHistorySize()
  {
    synchronized (mInstanceLock)
    {
      ensureConsistentState();
      return mHistoricalRecords.size();
    }
  }

  /**
   * Ensures the model is in a consistent state which is the activities for the current intent have been loaded, the most recent history has been
   * read, and the activities are sorted.
   */
  private void ensureConsistentState()
  {
    boolean stateChanged = loadActivitiesIfNeeded();
    stateChanged |= readHistoricalDataIfNeeded();
    pruneExcessiveHistoricalRecordsIfNeeded();
    if (stateChanged)
    {
      sortActivitiesIfNeeded();
      notifyChanged();
    }
  }

  /**
   * Sorts the activities if necessary which is if there is a sorter, there are some activities to sort, and there is some historical data.
   * 
   * @return Whether sorting was performed.
   */
  private boolean sortActivitiesIfNeeded()
  {
    if (mActivitySorter != null && mIntent != null && !mActivities.isEmpty() && !mHistoricalRecords.isEmpty())
    {
      mActivitySorter.sort(mIntent, mActivities, Collections.unmodifiableList(mHistoricalRecords));
      return true;
    }
    return false;
  }

  /**
   * Loads the activities for the current intent if needed which is if they are not already loaded for the current intent.
   * 
   * @return Whether loading was performed.
   */
  private boolean loadActivitiesIfNeeded()
  {
    if (mReloadActivities && mIntent != null)
    {
      mReloadActivities = false;
      mActivities.clear();
      List<ResolveInfo> resolveInfos = mContext.getPackageManager().queryIntentActivities(mIntent, 0);
      final int resolveInfoCount = resolveInfos.size();
      for (int i = 0; i < resolveInfoCount; i++)
      {
        ResolveInfo resolveInfo = resolveInfos.get(i);
        mActivities.add(new ActivityResolveInfo(resolveInfo));
      }
      return true;
    }
    return false;
  }

  /**
   * Reads the historical data if necessary which is it has changed, there is a history file, and there is not persist in progress.
   * 
   * @return Whether reading was performed.
   */
  private boolean readHistoricalDataIfNeeded()
  {
    if (mCanReadHistoricalData && mHistoricalRecordsChanged && !TextUtils.isEmpty(mHistoryFileName))
    {
      mCanReadHistoricalData = false;
      mReadShareHistoryCalled = true;
      readHistoricalDataImpl();
      return true;
    }
    return false;
  }

  /**
   * Adds a historical record.
   * 
   * @param historicalRecord
   *          The record to add.
   * @return True if the record was added.
   */
  private boolean addHisoricalRecord(HistoricalRecord historicalRecord)
  {
    final boolean added = mHistoricalRecords.add(historicalRecord);
    if (added)
    {
      mHistoricalRecordsChanged = true;
      pruneExcessiveHistoricalRecordsIfNeeded();
      persistHistoricalDataIfNeeded();
      sortActivitiesIfNeeded();
      notifyChanged();
    }
    return added;
  }

  /**
   * Prunes older excessive records to guarantee maxHistorySize.
   */
  private void pruneExcessiveHistoricalRecordsIfNeeded()
  {
    final int pruneCount = mHistoricalRecords.size() - mHistoryMaxSize;
    if (pruneCount <= 0)
    {
      return;
    }
    mHistoricalRecordsChanged = true;
    for (int i = 0; i < pruneCount; i++)
    {
      HistoricalRecord prunedRecord = mHistoricalRecords.remove(0);
      if (DEBUG)
      {
        Log.i(LOG_TAG, "Pruned: " + prunedRecord);
      }
    }
  }

  /**
   * Represents a record in the history.
   */
  public final static class HistoricalRecord
  {

    /**
     * The activity name.
     */
    public final ComponentName activity;

    /**
     * The choice time.
     */
    public final long time;

    /**
     * The record weight.
     */
    public final float weight;

    /**
     * Creates a new instance.
     * 
     * @param activityName
     *          The activity component name flattened to string.
     * @param time
     *          The time the activity was chosen.
     * @param weight
     *          The weight of the record.
     */
    public HistoricalRecord(String activityName, long time, float weight)
    {
      this(ComponentName.unflattenFromString(activityName), time, weight);
    }

    /**
     * Creates a new instance.
     * 
     * @param activityName
     *          The activity name.
     * @param time
     *          The time the activity was chosen.
     * @param weight
     *          The weight of the record.
     */
    public HistoricalRecord(ComponentName activityName, long time, float weight)
    {
      this.activity = activityName;
      this.time = time;
      this.weight = weight;
    }

    @Override
    public int hashCode()
    {
      final int prime = 31;
      int result = 1;
      result = prime * result + ((activity == null) ? 0 : activity.hashCode());
      result = prime * result + (int) (time ^ (time >>> 32));
      result = prime * result + Float.floatToIntBits(weight);
      return result;
    }

    @Override
    public boolean equals(Object obj)
    {
      if (this == obj)
      {
        return true;
      }
      if (obj == null)
      {
        return false;
      }
      if (getClass() != obj.getClass())
      {
        return false;
      }
      HistoricalRecord other = (HistoricalRecord) obj;
      if (activity == null)
      {
        if (other.activity != null)
        {
          return false;
        }
      }
      else if (!activity.equals(other.activity))
      {
        return false;
      }
      if (time != other.time)
      {
        return false;
      }
      if (Float.floatToIntBits(weight) != Float.floatToIntBits(other.weight))
      {
        return false;
      }
      return true;
    }

    @Override
    public String toString()
    {
      StringBuilder builder = new StringBuilder();
      builder.append("[");
      builder.append("; activity:").append(activity);
      builder.append("; time:").append(time);
      builder.append("; weight:").append(new BigDecimal(weight));
      builder.append("]");
      return builder.toString();
    }
  }

  /**
   * Represents an activity.
   */
  public final class ActivityResolveInfo
      implements Comparable<ActivityResolveInfo>
  {

    /**
     * The {@link ResolveInfo} of the activity.
     */
    public final ResolveInfo resolveInfo;

    /**
     * Weight of the activity. Useful for sorting.
     */
    public float weight;

    /**
     * Creates a new instance.
     * 
     * @param resolveInfo
     *          activity {@link ResolveInfo}.
     */
    public ActivityResolveInfo(ResolveInfo resolveInfo)
    {
      this.resolveInfo = resolveInfo;
    }

    @Override
    public int hashCode()
    {
      return 31 + Float.floatToIntBits(weight);
    }

    @Override
    public boolean equals(Object obj)
    {
      if (this == obj)
      {
        return true;
      }
      if (obj == null)
      {
        return false;
      }
      if (getClass() != obj.getClass())
      {
        return false;
      }
      ActivityResolveInfo other = (ActivityResolveInfo) obj;
      if (Float.floatToIntBits(weight) != Float.floatToIntBits(other.weight))
      {
        return false;
      }
      return true;
    }

    @Override
    public int compareTo(ActivityResolveInfo another)
    {
      return Float.floatToIntBits(another.weight) - Float.floatToIntBits(weight);
    }

    @Override
    public String toString()
    {
      StringBuilder builder = new StringBuilder();
      builder.append("[");
      builder.append("resolveInfo:").append(resolveInfo.toString());
      builder.append("; weight:").append(new BigDecimal(weight));
      builder.append("]");
      return builder.toString();
    }
  }

  /**
   * Default activity sorter implementation.
   */
  private final class DefaultSorter
      implements ActivitySorter
  {
    private static final float WEIGHT_DECAY_COEFFICIENT = 0.95f;

    private final Map<String, ActivityResolveInfo> mPackageNameToActivityMap = new HashMap<String, ActivityResolveInfo>();

    @Override
    public void sort(Intent intent, List<ActivityResolveInfo> activities, List<HistoricalRecord> historicalRecords)
    {
      Map<String, ActivityResolveInfo> packageNameToActivityMap = mPackageNameToActivityMap;
      packageNameToActivityMap.clear();

      final int activityCount = activities.size();
      for (int i = 0; i < activityCount; i++)
      {
        ActivityResolveInfo activity = activities.get(i);
        activity.weight = 0.0f;
        String packageName = activity.resolveInfo.activityInfo.packageName;
        packageNameToActivityMap.put(packageName, activity);
      }

      final int lastShareIndex = historicalRecords.size() - 1;
      float nextRecordWeight = 1;
      for (int i = lastShareIndex; i >= 0; i--)
      {
        HistoricalRecord historicalRecord = historicalRecords.get(i);
        String packageName = historicalRecord.activity.getPackageName();
        ActivityResolveInfo activity = packageNameToActivityMap.get(packageName);
        if (activity != null)
        {
          activity.weight += historicalRecord.weight * nextRecordWeight;
          nextRecordWeight = nextRecordWeight * WEIGHT_DECAY_COEFFICIENT;
        }
      }

      Collections.sort(activities);

      if (DEBUG)
      {
        for (int i = 0; i < activityCount; i++)
        {
          Log.i(LOG_TAG, "Sorted: " + activities.get(i));
        }
      }
    }
  }

  /**
   * Command for reading the historical records from a file off the UI thread.
   */
  private void readHistoricalDataImpl()
  {
    FileInputStream fis = null;
    try
    {
      fis = mContext.openFileInput(mHistoryFileName);
    }
    catch (FileNotFoundException fnfe)
    {
      if (DEBUG)
      {
        Log.i(LOG_TAG, "Could not open historical records file: " + mHistoryFileName);
      }
      return;
    }
    try
    {
      XmlPullParser parser = Xml.newPullParser();
      parser.setInput(fis, null);

      int type = XmlPullParser.START_DOCUMENT;
      while (type != XmlPullParser.END_DOCUMENT && type != XmlPullParser.START_TAG)
      {
        type = parser.next();
      }

      if (!TAG_HISTORICAL_RECORDS.equals(parser.getName()))
      {
        throw new XmlPullParserException("Share records file does not start with " + TAG_HISTORICAL_RECORDS + " tag.");
      }

      List<HistoricalRecord> historicalRecords = mHistoricalRecords;
      historicalRecords.clear();

      while (true)
      {
        type = parser.next();
        if (type == XmlPullParser.END_DOCUMENT)
        {
          break;
        }
        if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT)
        {
          continue;
        }
        String nodeName = parser.getName();
        if (!TAG_HISTORICAL_RECORD.equals(nodeName))
        {
          throw new XmlPullParserException("Share records file not well-formed.");
        }

        String activity = parser.getAttributeValue(null, ATTRIBUTE_ACTIVITY);
        final long time = Long.parseLong(parser.getAttributeValue(null, ATTRIBUTE_TIME));
        final float weight = Float.parseFloat(parser.getAttributeValue(null, ATTRIBUTE_WEIGHT));
        HistoricalRecord readRecord = new HistoricalRecord(activity, time, weight);
        historicalRecords.add(readRecord);

        if (DEBUG)
        {
          Log.i(LOG_TAG, "Read " + readRecord.toString());
        }
      }

      if (DEBUG)
      {
        Log.i(LOG_TAG, "Read " + historicalRecords.size() + " historical records.");
      }
    }
    catch (XmlPullParserException xppe)
    {
      Log.e(LOG_TAG, "Error reading historical recrod file: " + mHistoryFileName, xppe);
    }
    catch (IOException ioe)
    {
      Log.e(LOG_TAG, "Error reading historical recrod file: " + mHistoryFileName, ioe);
    }
    finally
    {
      if (fis != null)
      {
        try
        {
          fis.close();
        }
        catch (IOException ioe)
        {
          /* ignore */
        }
      }
    }
  }

  /**
   * Command for persisting the historical records to a file off the UI thread.
   */
  private final class PersistHistoryAsyncTask
      extends AsyncTask<Object, Void, Void>
  {

    @Override
    @SuppressWarnings("unchecked")
    public Void doInBackground(Object... args)
    {
      List<HistoricalRecord> historicalRecords = (List<HistoricalRecord>) args[0];
      String hostoryFileName = (String) args[1];

      FileOutputStream fos = null;

      try
      {
        fos = mContext.openFileOutput(hostoryFileName, Context.MODE_PRIVATE);
      }
      catch (FileNotFoundException fnfe)
      {
        Log.e(LOG_TAG, "Error writing historical recrod file: " + hostoryFileName, fnfe);
        return null;
      }

      XmlSerializer serializer = Xml.newSerializer();

      try
      {
        serializer.setOutput(fos, null);
        serializer.startDocument("UTF-8", true);
        serializer.startTag(null, TAG_HISTORICAL_RECORDS);

        final int recordCount = historicalRecords.size();
        for (int i = 0; i < recordCount; i++)
        {
          HistoricalRecord record = historicalRecords.remove(0);
          serializer.startTag(null, TAG_HISTORICAL_RECORD);
          serializer.attribute(null, ATTRIBUTE_ACTIVITY, record.activity.flattenToString());
          serializer.attribute(null, ATTRIBUTE_TIME, String.valueOf(record.time));
          serializer.attribute(null, ATTRIBUTE_WEIGHT, String.valueOf(record.weight));
          serializer.endTag(null, TAG_HISTORICAL_RECORD);
          if (DEBUG)
          {
            Log.i(LOG_TAG, "Wrote " + record.toString());
          }
        }

        serializer.endTag(null, TAG_HISTORICAL_RECORDS);
        serializer.endDocument();

        if (DEBUG)
        {
          Log.i(LOG_TAG, "Wrote " + recordCount + " historical records.");
        }
      }
      catch (IllegalArgumentException iae)
      {
        Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, iae);
      }
      catch (IllegalStateException ise)
      {
        Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, ise);
      }
      catch (IOException ioe)
      {
        Log.e(LOG_TAG, "Error writing historical recrod file: " + mHistoryFileName, ioe);
      }
      finally
      {
        mCanReadHistoricalData = true;
        if (fos != null)
        {
          try
          {
            fos.close();
          }
          catch (IOException e)
          {
            /* ignore */
          }
        }
      }
      return null;
    }
  }
}

Le fichier MyActivityChooserView.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package fr.rolandl.blog.shareactionprovider;

import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.database.DataSetObserver;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ActionProvider;
import android.support.v7.appcompat.R;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListPopupWindow;
import android.widget.PopupWindow;
import android.widget.TextView;

/**
 * This class is a view for choosing an activity for handling a given {@link Intent}.
 * <p>
 * The view is composed of two adjacent buttons:
 * <ul>
 * <li>
 * The left button is an immediate action and allows one click activity choosing. Tapping this button immediately executes the intent without
 * requiring any further user input. Long press on this button shows a popup for changing the default activity.</li>
 * <li>
 * The right button is an overflow action and provides an optimized menu of additional activities. Tapping this button shows a popup anchored to this
 * view, listing the most frequently used activities. This list is initially limited to a small number of items in frequency used order. The last
 * item, "Show all..." serves as an affordance to display all available activities.</li>
 * </ul>
 * </p>
 * 
 * @hide
 */
public class MyActivityChooserView
    extends ViewGroup
    implements MyActivityChooserModel.ActivityChooserModelClient
{

  /**
   * An adapter for displaying the activities in an {@link android.widget.AdapterView}.
   */
  private final ActivityChooserViewAdapter mAdapter;

  /**
   * Implementation of various interfaces to avoid publishing them in the APIs.
   */
  private final Callbacks mCallbacks;

  /**
   * The content of this view.
   */
  private final LinearLayout mActivityChooserContent;

  /**
   * Stores the background drawable to allow hiding and latter showing.
   */
  private final Drawable mActivityChooserContentBackground;

  /**
   * The expand activities action button;
   */
  private final FrameLayout mExpandActivityOverflowButton;

  /**
   * The image for the expand activities action button;
   */
  private final ImageView mExpandActivityOverflowButtonImage;

  /**
   * The default activities action button;
   */
  private final FrameLayout mDefaultActivityButton;

  /**
   * The image for the default activities action button;
   */
  private final ImageView mDefaultActivityButtonImage;

  /**
   * The maximal width of the list popup.
   */
  private final int mListPopupMaxWidth;

  /**
   * The ActionProvider hosting this view, if applicable.
   */
  ActionProvider mProvider;

  /**
   * Observer for the model data.
   */
  private final DataSetObserver mModelDataSetOberver = new DataSetObserver()
  {

    @Override
    public void onChanged()
    {
      super.onChanged();
      mAdapter.notifyDataSetChanged();
    }

    @Override
    public void onInvalidated()
    {
      super.onInvalidated();
      mAdapter.notifyDataSetInvalidated();
    }
  };

  private final OnGlobalLayoutListener mOnGlobalLayoutListener = new OnGlobalLayoutListener()
  {
    @Override
    public void onGlobalLayout()
    {
      if (isShowingPopup())
      {
        if (!isShown())
        {
          getListPopupWindow().dismiss();
        }
        else
        {
          getListPopupWindow().show();
          if (mProvider != null)
          {
            mProvider.subUiVisibilityChanged(true);
          }
        }
      }
    }
  };

  /**
   * Popup window for showing the activity overflow list.
   */
  private ListPopupWindow mListPopupWindow;

  /**
   * Listener for the dismissal of the popup/alert.
   */
  private PopupWindow.OnDismissListener mOnDismissListener;

  /**
   * Flag whether a default activity currently being selected.
   */
  private boolean mIsSelectingDefaultActivity;

  /**
   * The count of activities in the popup.
   */
  private int mInitialActivityCount = ActivityChooserViewAdapter.MAX_ACTIVITY_COUNT_DEFAULT;

  /**
   * Flag whether this view is attached to a window.
   */
  private boolean mIsAttachedToWindow;

  /**
   * String resource for formatting content description of the default target.
   */
  private int mDefaultActionButtonContentDescription;

  /**
   * Create a new instance.
   * 
   * @param context
   *          The application environment.
   */
  public MyActivityChooserView(Context context)
  {
    this(context, null);
  }

  /**
   * Create a new instance.
   * 
   * @param context
   *          The application environment.
   * @param attrs
   *          A collection of attributes.
   */
  public MyActivityChooserView(Context context, AttributeSet attrs)
  {
    this(context, attrs, 0);
  }

  /**
   * Create a new instance.
   * 
   * @param context
   *          The application environment.
   * @param attrs
   *          A collection of attributes.
   * @param defStyle
   *          The default style to apply to this view.
   */
  public MyActivityChooserView(Context context, AttributeSet attrs, int defStyle)
  {
    super(context, attrs, defStyle);

    TypedArray attributesArray = context.obtainStyledAttributes(attrs, R.styleable.ActivityChooserView, defStyle, 0);

    mInitialActivityCount = attributesArray.getInt(R.styleable.ActivityChooserView_initialActivityCount, ActivityChooserViewAdapter.MAX_ACTIVITY_COUNT_DEFAULT);

    Drawable expandActivityOverflowButtonDrawable = attributesArray.getDrawable(R.styleable.ActivityChooserView_expandActivityOverflowButtonDrawable);

    attributesArray.recycle();

    LayoutInflater inflater = LayoutInflater.from(getContext());
    inflater.inflate(R.layout.abc_activity_chooser_view, this, true);

    mCallbacks = new Callbacks();

    mActivityChooserContent = (LinearLayout) findViewById(R.id.activity_chooser_view_content);
    mActivityChooserContentBackground = mActivityChooserContent.getBackground();

    mDefaultActivityButton = (FrameLayout) findViewById(R.id.default_activity_button);
    mDefaultActivityButton.setOnClickListener(mCallbacks);
    mDefaultActivityButton.setOnLongClickListener(mCallbacks);
    mDefaultActivityButtonImage = (ImageView) mDefaultActivityButton.findViewById(R.id.image);

    mExpandActivityOverflowButton = (FrameLayout) findViewById(R.id.expand_activities_button);
    mExpandActivityOverflowButton.setOnClickListener(mCallbacks);
    mExpandActivityOverflowButtonImage = (ImageView) mExpandActivityOverflowButton.findViewById(R.id.image);
    mExpandActivityOverflowButtonImage.setImageDrawable(expandActivityOverflowButtonDrawable);

    mAdapter = new ActivityChooserViewAdapter();
    mAdapter.registerDataSetObserver(new DataSetObserver()
    {
      @Override
      public void onChanged()
      {
        super.onChanged();
        updateAppearance();
      }
    });

    Resources resources = context.getResources();
    mListPopupMaxWidth = Math.max(resources.getDisplayMetrics().widthPixels / 2, resources.getDimensionPixelSize(R.dimen.abc_config_prefDialogWidth));
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void setActivityChooserModel(MyActivityChooserModel dataModel)
  {
    mAdapter.setDataModel(dataModel);
    if (isShowingPopup())
    {
      dismissPopup();
      showPopup();
    }
  }

  /**
   * Sets the background for the button that expands the activity overflow list.
   * 
   * <strong>Note:</strong> Clients would like to set this drawable as a clue about the action the chosen activity will perform. For example, if a
   * share activity is to be chosen the drawable should give a clue that sharing is to be performed.
   * 
   * @param drawable
   *          The drawable.
   */
  public void setExpandActivityOverflowButtonDrawable(Drawable drawable)
  {
    mExpandActivityOverflowButtonImage.setImageDrawable(drawable);
  }

  /**
   * Sets the content description for the button that expands the activity overflow list.
   * 
   * description as a clue about the action performed by the button. For example, if a share activity is to be chosen the content description should
   * be something like "Share with".
   * 
   * @param resourceId
   *          The content description resource id.
   */
  public void setExpandActivityOverflowButtonContentDescription(int resourceId)
  {
    CharSequence contentDescription = getContext().getString(resourceId);
    mExpandActivityOverflowButtonImage.setContentDescription(contentDescription);
  }

  /**
   * Set the provider hosting this view, if applicable.
   * 
   * @hide Internal use only
   */
  public void setProvider(ActionProvider provider)
  {
    mProvider = provider;
  }

  /**
   * Shows the popup window with activities.
   * 
   * @return True if the popup was shown, false if already showing.
   */
  public boolean showPopup()
  {
    if (isShowingPopup() || !mIsAttachedToWindow)
    {
      return false;
    }
    mIsSelectingDefaultActivity = false;
    showPopupUnchecked(mInitialActivityCount);
    return true;
  }

  /**
   * Shows the popup no matter if it was already showing.
   * 
   * @param maxActivityCount
   *          The max number of activities to display.
   */
  private void showPopupUnchecked(int maxActivityCount)
  {
    if (mAdapter.getDataModel() == null)
    {
      throw new IllegalStateException("No data model. Did you call #setDataModel?");
    }

    getViewTreeObserver().addOnGlobalLayoutListener(mOnGlobalLayoutListener);

    final boolean defaultActivityButtonShown = mDefaultActivityButton.getVisibility() == VISIBLE;

    final int activityCount = mAdapter.getActivityCount();
    final int maxActivityCountOffset = defaultActivityButtonShown ? 1 : 0;
    if (maxActivityCount != ActivityChooserViewAdapter.MAX_ACTIVITY_COUNT_UNLIMITED && activityCount > maxActivityCount + maxActivityCountOffset)
    {
      mAdapter.setShowFooterView(true);
      mAdapter.setMaxActivityCount(maxActivityCount - 1);
    }
    else
    {
      mAdapter.setShowFooterView(false);
      mAdapter.setMaxActivityCount(maxActivityCount);
    }

    ListPopupWindow popupWindow = getListPopupWindow();
    if (!popupWindow.isShowing())
    {
      if (mIsSelectingDefaultActivity || !defaultActivityButtonShown)
      {
        mAdapter.setShowDefaultActivity(true, defaultActivityButtonShown);
      }
      else
      {
        mAdapter.setShowDefaultActivity(false, false);
      }
      final int contentWidth = Math.min(mAdapter.measureContentWidth(), mListPopupMaxWidth);
      popupWindow.setContentWidth(contentWidth);
      popupWindow.show();
      if (mProvider != null)
      {
        mProvider.subUiVisibilityChanged(true);
      }
      popupWindow.getListView().setContentDescription(getContext().getString(R.string.abc_activitychooserview_choose_application));
    }
  }

  /**
   * Dismisses the popup window with activities.
   * 
   * @return True if dismissed, false if already dismissed.
   */
  public boolean dismissPopup()
  {
    if (isShowingPopup())
    {
      getListPopupWindow().dismiss();
      ViewTreeObserver viewTreeObserver = getViewTreeObserver();
      if (viewTreeObserver.isAlive())
      {
        viewTreeObserver.removeGlobalOnLayoutListener(mOnGlobalLayoutListener);
      }
    }
    return true;
  }

  /**
   * Gets whether the popup window with activities is shown.
   * 
   * @return True if the popup is shown.
   */
  public boolean isShowingPopup()
  {
    return getListPopupWindow().isShowing();
  }

  @Override
  protected void onAttachedToWindow()
  {
    super.onAttachedToWindow();
    MyActivityChooserModel dataModel = mAdapter.getDataModel();
    if (dataModel != null)
    {
      dataModel.registerObserver(mModelDataSetOberver);
    }
    mIsAttachedToWindow = true;
  }

  @Override
  protected void onDetachedFromWindow()
  {
    super.onDetachedFromWindow();
    MyActivityChooserModel dataModel = mAdapter.getDataModel();
    if (dataModel != null)
    {
      dataModel.unregisterObserver(mModelDataSetOberver);
    }
    ViewTreeObserver viewTreeObserver = getViewTreeObserver();
    if (viewTreeObserver.isAlive())
    {
      viewTreeObserver.removeGlobalOnLayoutListener(mOnGlobalLayoutListener);
    }
    if (isShowingPopup())
    {
      dismissPopup();
    }
    mIsAttachedToWindow = false;
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
  {
    View child = mActivityChooserContent;
    // If the default action is not visible we want to be as tall as the
    // ActionBar so if this widget is used in the latter it will look as
    // a normal action button.
    if (mDefaultActivityButton.getVisibility() != VISIBLE)
    {
      heightMeasureSpec = MeasureSpec.makeMeasureSpec(MeasureSpec.getSize(heightMeasureSpec), MeasureSpec.EXACTLY);
    }
    measureChild(child, widthMeasureSpec, heightMeasureSpec);
    setMeasuredDimension(child.getMeasuredWidth(), child.getMeasuredHeight());
  }

  @Override
  protected void onLayout(boolean changed, int left, int top, int right, int bottom)
  {
    mActivityChooserContent.layout(0, 0, right - left, bottom - top);
    if (!isShowingPopup())
    {
      dismissPopup();
    }
  }

  public MyActivityChooserModel getDataModel()
  {
    return mAdapter.getDataModel();
  }

  /**
   * Sets a listener to receive a callback when the popup is dismissed.
   * 
   * @param listener
   *          The listener to be notified.
   */
  public void setOnDismissListener(PopupWindow.OnDismissListener listener)
  {
    mOnDismissListener = listener;
  }

  /**
   * Sets the initial count of items shown in the activities popup i.e. the items before the popup is expanded. This is an upper bound since it is not
   * guaranteed that such number of intent handlers exist.
   * 
   * @param itemCount
   *          The initial popup item count.
   */
  public void setInitialActivityCount(int itemCount)
  {
    mInitialActivityCount = itemCount;
  }

  /**
   * Sets a content description of the default action button. This resource should be a string taking one formatting argument and will be used for
   * formatting the content description of the button dynamically as the default target changes. For example, a resource pointing to the string
   * "share with %1$s" will result in a content description "share with Bluetooth" for the Bluetooth activity.
   * 
   * @param resourceId
   *          The resource id.
   */
  public void setDefaultActionButtonContentDescription(int resourceId)
  {
    mDefaultActionButtonContentDescription = resourceId;
  }

  /**
   * Gets the list popup window which is lazily initialized.
   * 
   * @return The popup.
   */
  private ListPopupWindow getListPopupWindow()
  {
    if (mListPopupWindow == null)
    {
      mListPopupWindow = new ListPopupWindow(getContext());
      mListPopupWindow.setAdapter(mAdapter);
      mListPopupWindow.setAnchorView(MyActivityChooserView.this);
      mListPopupWindow.setModal(true);
      mListPopupWindow.setOnItemClickListener(mCallbacks);
      mListPopupWindow.setOnDismissListener(mCallbacks);
    }
    return mListPopupWindow;
  }

  /**
   * Updates the buttons state.
   */
  private void updateAppearance()
  {
    // Expand overflow button.
    if (mAdapter.getCount() > 0)
    {
      mExpandActivityOverflowButton.setEnabled(true);
    }
    else
    {
      mExpandActivityOverflowButton.setEnabled(false);
    }
    // Default activity button.
    final int activityCount = mAdapter.getActivityCount();
    final int historySize = mAdapter.getHistorySize();
    if (activityCount == 1 || activityCount > 1 && historySize > 0)
    {
      mDefaultActivityButton.setVisibility(VISIBLE);
      ResolveInfo activity = mAdapter.getDefaultActivity();
      PackageManager packageManager = getContext().getPackageManager();
      mDefaultActivityButtonImage.setImageDrawable(activity.loadIcon(packageManager));
      if (mDefaultActionButtonContentDescription != 0)
      {
        CharSequence label = activity.loadLabel(packageManager);
        String contentDescription = getContext().getString(mDefaultActionButtonContentDescription, label);
        mDefaultActivityButton.setContentDescription(contentDescription);
      }
    }
    else
    {
      mDefaultActivityButton.setVisibility(View.GONE);
    }
    // Activity chooser content.
    if (mDefaultActivityButton.getVisibility() == VISIBLE)
    {
      mActivityChooserContent.setBackgroundDrawable(mActivityChooserContentBackground);
    }
    else
    {
      mActivityChooserContent.setBackgroundDrawable(null);
    }
  }

  /**
   * Interface implementation to avoid publishing them in the APIs.
   */
  private class Callbacks
      implements AdapterView.OnItemClickListener, View.OnClickListener, View.OnLongClickListener, PopupWindow.OnDismissListener
  {

    // AdapterView#OnItemClickListener
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id)
    {
      ActivityChooserViewAdapter adapter = (ActivityChooserViewAdapter) parent.getAdapter();
      final int itemViewType = adapter.getItemViewType(position);
      switch (itemViewType)
      {
      case ActivityChooserViewAdapter.ITEM_VIEW_TYPE_FOOTER:
      {
        showPopupUnchecked(ActivityChooserViewAdapter.MAX_ACTIVITY_COUNT_UNLIMITED);
      }
        break;
      case ActivityChooserViewAdapter.ITEM_VIEW_TYPE_ACTIVITY:
      {
        dismissPopup();
        if (mIsSelectingDefaultActivity)
        {
          // The item at position zero is the default already.
          if (position > 0)
          {
            mAdapter.getDataModel().setDefaultActivity(position);
          }
        }
        else
        {
          // If the default target is not shown in the list, the first
          // item in the model is default action => adjust index
          position = mAdapter.getShowDefaultActivity() ? position : position + 1;
          Intent launchIntent = mAdapter.getDataModel().chooseActivity(position);
          if (launchIntent != null)
          {
            launchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
            getContext().startActivity(launchIntent);
          }
        }
      }
        break;
      default:
        throw new IllegalArgumentException();
      }
    }

    // View.OnClickListener
    @Override
    public void onClick(View view)
    {
      if (view == mDefaultActivityButton)
      {
        dismissPopup();
        ResolveInfo defaultActivity = mAdapter.getDefaultActivity();
        final int index = mAdapter.getDataModel().getActivityIndex(defaultActivity);
        Intent launchIntent = mAdapter.getDataModel().chooseActivity(index);
        if (launchIntent != null)
        {
          launchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
          getContext().startActivity(launchIntent);
        }
      }
      else if (view == mExpandActivityOverflowButton)
      {
        mIsSelectingDefaultActivity = false;
        showPopupUnchecked(mInitialActivityCount);
      }
      else
      {
        throw new IllegalArgumentException();
      }
    }

    // OnLongClickListener#onLongClick
    @Override
    public boolean onLongClick(View view)
    {
      if (view == mDefaultActivityButton)
      {
        if (mAdapter.getCount() > 0)
        {
          mIsSelectingDefaultActivity = true;
          showPopupUnchecked(mInitialActivityCount);
        }
      }
      else
      {
        throw new IllegalArgumentException();
      }
      return true;
    }

    // PopUpWindow.OnDismissListener#onDismiss
    @Override
    public void onDismiss()
    {
      notifyOnDismissListener();
      if (mProvider != null)
      {
        mProvider.subUiVisibilityChanged(false);
      }
    }

    private void notifyOnDismissListener()
    {
      if (mOnDismissListener != null)
      {
        mOnDismissListener.onDismiss();
      }
    }
  }

  /**
   * Adapter for backing the list of activities shown in the popup.
   */
  private class ActivityChooserViewAdapter
      extends BaseAdapter
  {

    public static final int MAX_ACTIVITY_COUNT_UNLIMITED = Integer.MAX_VALUE;

    public static final int MAX_ACTIVITY_COUNT_DEFAULT = 4;

    private static final int ITEM_VIEW_TYPE_ACTIVITY = 0;

    private static final int ITEM_VIEW_TYPE_FOOTER = 1;

    private static final int ITEM_VIEW_TYPE_COUNT = 3;

    private MyActivityChooserModel mDataModel;

    private int mMaxActivityCount = MAX_ACTIVITY_COUNT_DEFAULT;

    private boolean mShowDefaultActivity;

    private boolean mHighlightDefaultActivity;

    private boolean mShowFooterView;

    public void setDataModel(MyActivityChooserModel dataModel)
    {
      MyActivityChooserModel oldDataModel = mAdapter.getDataModel();
      if (oldDataModel != null && isShown())
      {
        oldDataModel.unregisterObserver(mModelDataSetOberver);
      }
      mDataModel = dataModel;
      if (dataModel != null && isShown())
      {
        dataModel.registerObserver(mModelDataSetOberver);
      }
      notifyDataSetChanged();
    }

    @Override
    public int getItemViewType(int position)
    {
      if (mShowFooterView && position == getCount() - 1)
      {
        return ITEM_VIEW_TYPE_FOOTER;
      }
      else
      {
        return ITEM_VIEW_TYPE_ACTIVITY;
      }
    }

    @Override
    public int getViewTypeCount()
    {
      return ITEM_VIEW_TYPE_COUNT;
    }

    @Override
    public int getCount()
    {
      int count = 0;
      int activityCount = mDataModel.getActivityCount();
      if (!mShowDefaultActivity && mDataModel.getDefaultActivity() != null)
      {
        activityCount--;
      }
      count = Math.min(activityCount, mMaxActivityCount);
      if (mShowFooterView)
      {
        count++;
      }
      return count;
    }

    @Override
    public Object getItem(int position)
    {
      final int itemViewType = getItemViewType(position);
      switch (itemViewType)
      {
      case ITEM_VIEW_TYPE_FOOTER:
        return null;
      case ITEM_VIEW_TYPE_ACTIVITY:
        if (!mShowDefaultActivity && mDataModel.getDefaultActivity() != null)
        {
          position++;
        }
        return mDataModel.getActivity(position);
      default:
        throw new IllegalArgumentException();
      }
    }

    @Override
    public long getItemId(int position)
    {
      return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
      final int itemViewType = getItemViewType(position);
      switch (itemViewType)
      {
      case ITEM_VIEW_TYPE_FOOTER:
        if (convertView == null || convertView.getId() != ITEM_VIEW_TYPE_FOOTER)
        {
          convertView = LayoutInflater.from(getContext()).inflate(R.layout.abc_activity_chooser_view_list_item, parent, false);
          convertView.setId(ITEM_VIEW_TYPE_FOOTER);
          TextView titleView = (TextView) convertView.findViewById(R.id.title);
          titleView.setText(getContext().getString(R.string.abc_activity_chooser_view_see_all));
        }
        return convertView;
      case ITEM_VIEW_TYPE_ACTIVITY:
        if (convertView == null || convertView.getId() != R.id.list_item)
        {
          convertView = LayoutInflater.from(getContext()).inflate(R.layout.abc_activity_chooser_view_list_item, parent, false);
        }
        PackageManager packageManager = getContext().getPackageManager();
        // Set the icon
        ImageView iconView = (ImageView) convertView.findViewById(R.id.icon);
        ResolveInfo activity = (ResolveInfo) getItem(position);
        iconView.setImageDrawable(activity.loadIcon(packageManager));
        // Set the title.
        TextView titleView = (TextView) convertView.findViewById(R.id.title);
        titleView.setText(activity.loadLabel(packageManager));
        // Highlight the default.
        if (mShowDefaultActivity && position == 0 && mHighlightDefaultActivity)
        {
          // TODO convertView.setActivated(true);
        }
        else
        {
          // TODO convertView.setActivated(false);
        }
        return convertView;
      default:
        throw new IllegalArgumentException();
      }
    }

    public int measureContentWidth()
    {
      // The user may have specified some of the target not to be shown but we
      // want to measure all of them since after expansion they should fit.
      final int oldMaxActivityCount = mMaxActivityCount;
      mMaxActivityCount = MAX_ACTIVITY_COUNT_UNLIMITED;

      int contentWidth = 0;
      View itemView = null;

      final int widthMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
      final int heightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
      final int count = getCount();

      for (int i = 0; i < count; i++)
      {
        itemView = getView(i, itemView, null);
        itemView.measure(widthMeasureSpec, heightMeasureSpec);
        contentWidth = Math.max(contentWidth, itemView.getMeasuredWidth());
      }

      mMaxActivityCount = oldMaxActivityCount;

      return contentWidth;
    }

    public void setMaxActivityCount(int maxActivityCount)
    {
      if (mMaxActivityCount != maxActivityCount)
      {
        mMaxActivityCount = maxActivityCount;
        notifyDataSetChanged();
      }
    }

    public ResolveInfo getDefaultActivity()
    {
      return mDataModel.getDefaultActivity();
    }

    public void setShowFooterView(boolean showFooterView)
    {
      if (mShowFooterView != showFooterView)
      {
        mShowFooterView = showFooterView;
        notifyDataSetChanged();
      }
    }

    public int getActivityCount()
    {
      return mDataModel.getActivityCount();
    }

    public int getHistorySize()
    {
      return mDataModel.getHistorySize();
    }

    public int getMaxActivityCount()
    {
      return mMaxActivityCount;
    }

    public MyActivityChooserModel getDataModel()
    {
      return mDataModel;
    }

    public void setShowDefaultActivity(boolean showDefaultActivity, boolean highlightDefaultActivity)
    {
      if (mShowDefaultActivity != showDefaultActivity || mHighlightDefaultActivity != highlightDefaultActivity)
      {
        mShowDefaultActivity = showDefaultActivity;
        mHighlightDefaultActivity = highlightDefaultActivity;
        notifyDataSetChanged();
      }
    }

    public boolean getShowDefaultActivity()
    {
      return mShowDefaultActivity;
    }
  }
}

Le fichier MyShareActionProvider.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package fr.rolandl.blog.shareactionprovider;

import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ActionProvider;
import android.support.v7.appcompat.R;
import android.util.TypedValue;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.SubMenu;
import android.view.View;
import fr.rolandl.blog.shareactionprovider.MyActivityChooserModel.OnChooseActivityListener;

/**
 * This is a provider for a share action. It is responsible for creating views that enable data sharing and also to show a sub menu with sharing
 * activities if the hosting item is placed on the overflow menu.
 * 
 * <p class="note">
 * <strong>Note:</strong> This class is included in the <a href="{@docRoot}tools/extras/support-library.html">support library</a> for compatibility
 * with API level 7 and higher. If you're developing your app for API level 14 and higher <em>only</em>, you should instead use the framework
 * {@link android.widget.ShareActionProvider} class.
 * </p>
 * 
 * <p>
 * Here is how to use the action provider with custom backing file in a {@link MenuItem}:
 * </p>
 * 
 * <pre>
 * <code>
 *  // In {@link android.app.Activity#onCreateOptionsMenu Activity.onCreateOptionsMenu()}
 *  public boolean onCreateOptionsMenu(Menu menu) {
 *      // Get the menu item.
 *      MenuItem menuItem = menu.findItem(R.id.my_menu_item);
 *      // Get the provider and hold onto it to set/change the share intent.
 *      mShareActionProvider = (ShareActionProvider) MenuItemCompat.getActionProvider(menuItem);
 *      // Set history different from the default before getting the action
 *      // view since a call to {@link android.support.v4.view.MenuItemCompat#getActionView(android.view.MenuItem) MenuItemCompat.getActionView()} calls
 *      // {@link ActionProvider#onCreateActionView()} which uses the backing file name. Omit this
 *      // line if using the default share history file is desired.
 *      mShareActionProvider.setShareHistoryFileName("custom_share_history.xml");
 *      . . .
 *  }
 * 
 *  // Somewhere in the application.
 *  public void doShare(Intent shareIntent) {
 *      // When you want to share set the share intent.
 *      mShareActionProvider.setShareIntent(shareIntent);
 *  }
 * </code>
 * </pre>
 * <p>
 * <strong>Note:</strong> While the sample snippet demonstrates how to use this provider in the context of a menu item, the use of the provider is not
 * limited to menu items.
 * </p>
 * 
 * <div class="special reference"> <h3>Developer Guides</h3>
 * 
 * <p>
 * For information about how to use {@link MyShareActionProvider}, see the
 * <a href="{@docRoot}, see the <a href="{@docRoot}guide/topics/ui/actionbar.html#ActionProvider">Action
 * Bar</a> API guide.
 * </p>
 * </div>
 * 
 * @see ActionProvider
 */
public class MyShareActionProvider
    extends ActionProvider
{

  /**
   * Listener for the event of selecting a share target.
   */
  public interface OnShareTargetSelectedListener
  {

    /**
     * Called when a share target has been selected. The client can decide whether to perform some action before the sharing is actually performed.
     * <p>
     * <strong>Note:</strong> Modifying the intent is not permitted and any changes to the latter will be ignored.
     * </p>
     * <p>
     * <strong>Note:</strong> You should <strong>not</strong> handle the intent here. This callback aims to notify the client that a sharing is being
     * performed, so the client can update the UI if necessary.
     * </p>
     * 
     * @param source
     *          The source of the notification.
     * @param intent
     *          The intent for launching the chosen share target.
     * @return The return result is ignored. Always return false for consistency.
     */
    public boolean onShareTargetSelected(MyShareActionProvider source, Intent intent);
  }

  /**
   * The default for the maximal number of activities shown in the sub-menu.
   */
  private static final int DEFAULT_INITIAL_ACTIVITY_COUNT = 4;

  /**
   * The the maximum number activities shown in the sub-menu.
   */
  private final int mMaxShownActivityCount = DEFAULT_INITIAL_ACTIVITY_COUNT;

  /**
   * Listener for handling menu item clicks.
   */
  private final ShareMenuItemOnMenuItemClickListener mOnMenuItemClickListener = new ShareMenuItemOnMenuItemClickListener();

  /**
   * The default name for storing share history.
   */
  public static final String DEFAULT_SHARE_HISTORY_FILE_NAME = "share_history.xml";

  /**
   * Context for accessing resources.
   */
  private final Context mContext;

  /**
   * The name of the file with share history data.
   */
  private String mShareHistoryFileName = DEFAULT_SHARE_HISTORY_FILE_NAME;

  private OnShareTargetSelectedListener mOnShareTargetSelectedListener;

  private OnChooseActivityListener mOnChooseActivityListener;

  /**
   * Creates a new instance.
   * 
   * @param context
   *          Context for accessing resources.
   */
  public MyShareActionProvider(Context context)
  {
    super(context);
    mContext = context;
  }

  /**
   * Sets a listener to be notified when a share target has been selected. The listener can optionally decide to handle the selection and not rely on
   * the default behavior which is to launch the activity.
   * <p>
   * <strong>Note:</strong> If you choose the backing share history file you will still be notified in this callback.
   * </p>
   * 
   * @param listener
   *          The listener.
   */
  public void setOnShareTargetSelectedListener(OnShareTargetSelectedListener listener)
  {
    mOnShareTargetSelectedListener = listener;
    setActivityChooserPolicyIfNeeded();
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public View onCreateActionView()
  {
    // Create the view and set its data model.
    MyActivityChooserModel dataModel = MyActivityChooserModel.get(mContext, mShareHistoryFileName);
    MyActivityChooserView activityChooserView = new MyActivityChooserView(mContext);
    activityChooserView.setActivityChooserModel(dataModel);

    // Lookup and set the expand action icon.
    TypedValue outTypedValue = new TypedValue();
    mContext.getTheme().resolveAttribute(R.attr.actionModeShareDrawable, outTypedValue, true);
    Drawable drawable = mContext.getResources().getDrawable(outTypedValue.resourceId);
    activityChooserView.setExpandActivityOverflowButtonDrawable(drawable);
    activityChooserView.setProvider(this);

    // Set content description.
    activityChooserView.setDefaultActionButtonContentDescription(R.string.abc_shareactionprovider_share_with_application);
    activityChooserView.setExpandActivityOverflowButtonContentDescription(R.string.abc_shareactionprovider_share_with);

    return activityChooserView;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public boolean hasSubMenu()
  {
    return true;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void onPrepareSubMenu(SubMenu subMenu)
  {
    // Clear since the order of items may change.
    subMenu.clear();

    MyActivityChooserModel dataModel = MyActivityChooserModel.get(mContext, mShareHistoryFileName);
    PackageManager packageManager = mContext.getPackageManager();

    final int expandedActivityCount = dataModel.getActivityCount();
    final int collapsedActivityCount = Math.min(expandedActivityCount, mMaxShownActivityCount);

    // Populate the sub-menu with a sub set of the activities.
    for (int i = 0; i < collapsedActivityCount; i++)
    {
      ResolveInfo activity = dataModel.getActivity(i);
      subMenu.add(0, i, i, activity.loadLabel(packageManager)).setIcon(activity.loadIcon(packageManager)).setOnMenuItemClickListener(mOnMenuItemClickListener);
    }

    if (collapsedActivityCount < expandedActivityCount)
    {
      // Add a sub-menu for showing all activities as a list item.
      SubMenu expandedSubMenu = subMenu.addSubMenu(Menu.NONE, collapsedActivityCount, collapsedActivityCount,
          mContext.getString(R.string.abc_activity_chooser_view_see_all));
      for (int i = 0; i < expandedActivityCount; i++)
      {
        ResolveInfo activity = dataModel.getActivity(i);
        expandedSubMenu.add(0, i, i, activity.loadLabel(packageManager)).setIcon(activity.loadIcon(packageManager)).setOnMenuItemClickListener(
            mOnMenuItemClickListener);
      }
    }
  }

  /**
   * Sets the file name of a file for persisting the share history which history will be used for ordering share targets. This file will be used for
   * all view created by {@link #onCreateActionView()}. Defaults to {@link #DEFAULT_SHARE_HISTORY_FILE_NAME}. Set to <code>null</code> if share
   * history should not be persisted between sessions.
   * <p>
   * <strong>Note:</strong> The history file name can be set any time, however only the action views created by {@link #onCreateActionView()} after
   * setting the file name will be backed by the provided file. Therefore, if you want to use different history files for sharing specific types of
   * content, every time you change the history file {@link #setShareHistoryFileName(String)} you must call
   * {@link android.app.Activity#invalidateOptionsMenu()} to recreate the action view. You should <strong>not</strong> call
   * {@link android.app.Activity#invalidateOptionsMenu()} from {@link android.app.Activity#onCreateOptionsMenu(Menu)}."
   * <p>
   * <code>
   * private void doShare(Intent intent) {
   *     if (IMAGE.equals(intent.getMimeType())) {
   *         mShareActionProvider.setHistoryFileName(SHARE_IMAGE_HISTORY_FILE_NAME);
   *     } else if (TEXT.equals(intent.getMimeType())) {
   *         mShareActionProvider.setHistoryFileName(SHARE_TEXT_HISTORY_FILE_NAME);
   *     }
   *     mShareActionProvider.setIntent(intent);
   *     invalidateOptionsMenu();
   * }
   * <code>
   * 
   * @param shareHistoryFile
   *          The share history file name.
   */
  public void setShareHistoryFileName(String shareHistoryFile)
  {
    mShareHistoryFileName = shareHistoryFile;
    setActivityChooserPolicyIfNeeded();
  }

  /**
   * Sets an intent with information about the share action. Here is a sample for constructing a share intent:
   * <p>
   * 
   * <pre>
   * <code>
   *  Intent shareIntent = new Intent(Intent.ACTION_SEND);
   *  shareIntent.setType("image/*");
   *  Uri uri = Uri.fromFile(new File(getFilesDir(), "foo.jpg"));
   *  shareIntent.putExtra(Intent.EXTRA_STREAM, uri.toString());
   * </pre>
   * 
   * </code>
   * </p>
   * 
   * @param shareIntent
   *          The share intent.
   * 
   * @see Intent#ACTION_SEND
   * @see Intent#ACTION_SEND_MULTIPLE
   */
  public void setShareIntent(Intent shareIntent)
  {
    MyActivityChooserModel dataModel = MyActivityChooserModel.get(mContext, mShareHistoryFileName);
    dataModel.setIntent(shareIntent);
  }

  /**
   * Reusable listener for handling share item clicks.
   */
  private class ShareMenuItemOnMenuItemClickListener
      implements OnMenuItemClickListener
  {
    @Override
    public boolean onMenuItemClick(MenuItem item)
    {
      MyActivityChooserModel dataModel = MyActivityChooserModel.get(mContext, mShareHistoryFileName);
      final int itemId = item.getItemId();
      Intent launchIntent = dataModel.chooseActivity(itemId);
      if (launchIntent != null)
      {
        launchIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
        mContext.startActivity(launchIntent);
      }
      return true;
    }
  }

  /**
   * Set the activity chooser policy of the model backed by the current share history file if needed which is if there is a registered callback.
   */
  private void setActivityChooserPolicyIfNeeded()
  {
    if (mOnShareTargetSelectedListener == null)
    {
      return;
    }
    if (mOnChooseActivityListener == null)
    {
      mOnChooseActivityListener = new ShareActivityChooserModelPolicy();
    }
    MyActivityChooserModel dataModel = MyActivityChooserModel.get(mContext, mShareHistoryFileName);
    dataModel.setOnChooseActivityListener(mOnChooseActivityListener);
  }

  /**
   * Policy that delegates to the {@link OnShareTargetSelectedListener}, if such.
   */
  private class ShareActivityChooserModelPolicy
      implements OnChooseActivityListener
  {
    @Override
    public boolean onChooseActivity(MyActivityChooserModel host, Intent intent)
    {
      if (mOnShareTargetSelectedListener != null)
      {
        mOnShareTargetSelectedListener.onShareTargetSelected(MyShareActionProvider.this, intent);
      }
      return false;
    }
  }
}

Commentaires