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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 
     18 package android.service.chooser;
     19 
     20 import android.annotation.SdkConstant;
     21 import android.app.Service;
     22 import android.content.ComponentName;
     23 import android.content.Intent;
     24 import android.content.IntentFilter;
     25 import android.os.IBinder;
     26 import android.os.RemoteException;
     27 import android.util.Log;
     28 
     29 import java.util.List;
     30 
     31 /**
     32  * A service that receives calls from the system when the user is asked to choose
     33  * a target for an intent explicitly by another app. The calling app must have invoked
     34  * {@link android.content.Intent#ACTION_CHOOSER ACTION_CHOOSER} as handled by the system;
     35  * applications do not have the ability to query a ChooserTargetService directly.
     36  *
     37  * <p>Which ChooserTargetServices are queried depends on a system-level policy decision
     38  * made at the moment the chooser is invoked, including but not limited to user time
     39  * spent with the app package or associated components in the foreground, recency of usage
     40  * or frequency of usage. These will generally correlate with the order that app targets
     41  * are shown in the list of intent handlers shown in the system chooser or resolver.</p>
     42  *
     43  * <p>To extend this class, you must declare the service in your manifest file with
     44  * the {@link android.Manifest.permission#BIND_CHOOSER_TARGET_SERVICE} permission
     45  * and include an intent filter with the {@link #SERVICE_INTERFACE} action. For example:</p>
     46  * <pre>
     47  *     &lt;service android:name=".MyChooserTargetService"
     48  *             android:label="&#64;string/service_name"
     49  *             android:permission="android.permission.BIND_CHOOSER_TARGET_SERVICE">
     50  *         &lt;intent-filter>
     51  *             &lt;action android:name="android.service.chooser.ChooserTargetService" />
     52  *         &lt;/intent-filter>
     53  *     &lt;/service>
     54  * </pre>
     55  *
     56  * <p>For the system to query your service, you must add a &lt;meta-data> element to the
     57  * Activity in your manifest that can handle Intents that you would also like to provide
     58  * optional deep links for. For example, a chat app might offer deep links to recent active
     59  * conversations instead of invoking a generic picker after the app itself is chosen as a target.
     60  * </p>
     61  *
     62  * <p>The meta-data element should have the name
     63  * <code>android.service.chooser.chooser_target_service</code> and a value corresponding to
     64  * the component name of your service. Example:</p>
     65  * <pre>
     66  *     &lt;activity android:name=".MyShareActivity"
     67  *             android:label="&#64;string/share_activity_label">
     68  *         &lt;intent-filter>
     69  *             &lt;action android:name="android.intent.action.SEND" />
     70  *         &lt;/intent-filter>
     71  *         &lt;meta-data android:name="android.service.chooser.chooser_target_service"
     72  *                 android:value=".MyChooserTargetService" />
     73  *     &lt;/activity>
     74  * </pre>
     75  */
     76 public abstract class ChooserTargetService extends Service {
     77     // TAG = "ChooserTargetService[MySubclass]";
     78     private final String TAG = ChooserTargetService.class.getSimpleName()
     79             + '[' + getClass().getSimpleName() + ']';
     80 
     81     private static final boolean DEBUG = false;
     82 
     83     /**
     84      * The Intent action that a ChooserTargetService must respond to
     85      */
     86     @SdkConstant(SdkConstant.SdkConstantType.SERVICE_ACTION)
     87     public static final String SERVICE_INTERFACE = "android.service.chooser.ChooserTargetService";
     88 
     89     /**
     90      * The name of the <code>meta-data</code> element that must be present on an
     91      * <code>activity</code> element in a manifest to link it to a ChooserTargetService
     92      */
     93     public static final String META_DATA_NAME = "android.service.chooser.chooser_target_service";
     94 
     95     /**
     96      * The permission that a ChooserTargetService must require in order to bind to it.
     97      * If this permission is not enforced the system will skip that ChooserTargetService.
     98      */
     99     public static final String BIND_PERMISSION = "android.permission.BIND_CHOOSER_TARGET_SERVICE";
    100 
    101     private IChooserTargetServiceWrapper mWrapper = null;
    102 
    103     /**
    104      * Called by the system to retrieve a set of deep-link {@link ChooserTarget targets} that
    105      * can handle an intent.
    106      *
    107      * <p>The returned list should be sorted such that the most relevant targets appear first.
    108      * The score for each ChooserTarget will be combined with the system's score for the original
    109      * target Activity to sort and filter targets presented to the user.</p>
    110      *
    111      * <p><em>Important:</em> Calls to this method from other applications will occur on
    112      * a binder thread, not on your app's main thread. Make sure that access to relevant data
    113      * within your app is thread-safe.</p>
    114      *
    115      * @param targetActivityName the ComponentName of the matched activity that referred the system
    116      *                           to this ChooserTargetService
    117      * @param matchedFilter the specific IntentFilter on the component that was matched
    118      * @return a list of deep-link targets to fulfill the intent match, sorted by relevance
    119      */
    120     public abstract List<ChooserTarget> onGetChooserTargets(ComponentName targetActivityName,
    121             IntentFilter matchedFilter);
    122 
    123     @Override
    124     public IBinder onBind(Intent intent) {
    125         if (DEBUG) Log.d(TAG, "onBind " + intent);
    126         if (!SERVICE_INTERFACE.equals(intent.getAction())) {
    127             if (DEBUG) Log.d(TAG, "bad intent action " + intent.getAction() + "; returning null");
    128             return null;
    129         }
    130 
    131         if (mWrapper == null) {
    132             mWrapper = new IChooserTargetServiceWrapper();
    133         }
    134         return mWrapper;
    135     }
    136 
    137     private class IChooserTargetServiceWrapper extends IChooserTargetService.Stub {
    138         @Override
    139         public void getChooserTargets(ComponentName targetComponentName,
    140                 IntentFilter matchedFilter, IChooserTargetResult result) throws RemoteException {
    141             List<ChooserTarget> targets = null;
    142             final long id = clearCallingIdentity();
    143             try {
    144                 if (DEBUG) {
    145                     Log.d(TAG, "getChooserTargets calling onGetChooserTargets; "
    146                             + targetComponentName + " filter: " + matchedFilter);
    147                 }
    148                 targets = onGetChooserTargets(targetComponentName, matchedFilter);
    149             } finally {
    150                 restoreCallingIdentity(id);
    151                 result.sendResult(targets);
    152                 if (DEBUG) Log.d(TAG, "Sent results");
    153             }
    154         }
    155     }
    156 }
    157