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      1 /*
      2  * Copyright (C) 2009 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 package android.os;
     18 
     19 import com.android.internal.os.IResultReceiver;
     20 
     21 /**
     22  * Generic interface for receiving a callback result from someone.  Use this
     23  * by creating a subclass and implement {@link #onReceiveResult}, which you can
     24  * then pass to others and send through IPC, and receive results they
     25  * supply with {@link #send}.
     26  */
     27 public class ResultReceiver implements Parcelable {
     28     final boolean mLocal;
     29     final Handler mHandler;
     30 
     31     IResultReceiver mReceiver;
     32 
     33     class MyRunnable implements Runnable {
     34         final int mResultCode;
     35         final Bundle mResultData;
     36 
     37         MyRunnable(int resultCode, Bundle resultData) {
     38             mResultCode = resultCode;
     39             mResultData = resultData;
     40         }
     41 
     42         public void run() {
     43             onReceiveResult(mResultCode, mResultData);
     44         }
     45     }
     46 
     47     class MyResultReceiver extends IResultReceiver.Stub {
     48         public void send(int resultCode, Bundle resultData) {
     49             if (mHandler != null) {
     50                 mHandler.post(new MyRunnable(resultCode, resultData));
     51             } else {
     52                 onReceiveResult(resultCode, resultData);
     53             }
     54         }
     55     }
     56 
     57     /**
     58      * Create a new ResultReceive to receive results.  Your
     59      * {@link #onReceiveResult} method will be called from the thread running
     60      * <var>handler</var> if given, or from an arbitrary thread if null.
     61      */
     62     public ResultReceiver(Handler handler) {
     63         mLocal = true;
     64         mHandler = handler;
     65     }
     66 
     67     /**
     68      * Deliver a result to this receiver.  Will call {@link #onReceiveResult},
     69      * always asynchronously if the receiver has supplied a Handler in which
     70      * to dispatch the result.
     71      * @param resultCode Arbitrary result code to deliver, as defined by you.
     72      * @param resultData Any additional data provided by you.
     73      */
     74     public void send(int resultCode, Bundle resultData) {
     75         if (mLocal) {
     76             if (mHandler != null) {
     77                 mHandler.post(new MyRunnable(resultCode, resultData));
     78             } else {
     79                 onReceiveResult(resultCode, resultData);
     80             }
     81             return;
     82         }
     83 
     84         if (mReceiver != null) {
     85             try {
     86                 mReceiver.send(resultCode, resultData);
     87             } catch (RemoteException e) {
     88             }
     89         }
     90     }
     91 
     92     /**
     93      * Override to receive results delivered to this object.
     94      *
     95      * @param resultCode Arbitrary result code delivered by the sender, as
     96      * defined by the sender.
     97      * @param resultData Any additional data provided by the sender.
     98      */
     99     protected void onReceiveResult(int resultCode, Bundle resultData) {
    100     }
    101 
    102     public int describeContents() {
    103         return 0;
    104     }
    105 
    106     public void writeToParcel(Parcel out, int flags) {
    107         synchronized (this) {
    108             if (mReceiver == null) {
    109                 mReceiver = new MyResultReceiver();
    110             }
    111             out.writeStrongBinder(mReceiver.asBinder());
    112         }
    113     }
    114 
    115     ResultReceiver(Parcel in) {
    116         mLocal = false;
    117         mHandler = null;
    118         mReceiver = IResultReceiver.Stub.asInterface(in.readStrongBinder());
    119     }
    120 
    121     public static final Parcelable.Creator<ResultReceiver> CREATOR
    122             = new Parcelable.Creator<ResultReceiver>() {
    123         public ResultReceiver createFromParcel(Parcel in) {
    124             return new ResultReceiver(in);
    125         }
    126         public ResultReceiver[] newArray(int size) {
    127             return new ResultReceiver[size];
    128         }
    129     };
    130 }
    131