guide/components/bound-services.jd

page.title=
parent.title=
parent.link=services.html
@jd:body


<div id="qv-wrapper">
<ol id="qv">
<h2></h2>
<ol>
  <li><a href="#Basics"></a></li>
  <li><a href="#Creating"></a>
    <ol>
      <li><a href="#Binder">Binder </a></li>
      <li><a href="#Messenger"></a></li>
    </ol>
  </li>
  <li><a href="#Binding"></a></li>
  <li><a href="#Lifecycle"></a></li>
</ol>

<h2></h2>
<ol>
  <li>{@link android.app.Service}</li>
  <li>{@link android.content.ServiceConnection}</li>
  <li>{@link android.os.IBinder}</li>
</ol>

<h2></h2>
<ol>
  <li><a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/RemoteService.html">{@code
      RemoteService}</a></li>
  <li><a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LocalService.html">{@code
      LocalService}</a></li>
</ol>

<h2></h2>
<ol>
  <li><a href="{@docRoot}guide/components/services.html"></a></li>
</ol>
</div>


<p> IPC


</p>

<p>
<a href="{@docRoot}guide/components/services.html"></a>

</p>


<h2 id="Basics"></h2>

<p> {@link android.app.Service}
{@link android.app.Service#onBind onBind()}
 {@link android.os.IBinder}

</p>

<div class="sidebox-wrapper">
<div class="sidebox">
  <h3></h3>

<p><a href="{@docRoot}guide/components/services.html"></a>
{@link android.content.Context#startService startService()}  {@link
android.content.Context#bindService bindService()}


  <p><em></em>
{@link android.app.Service#stopSelf stopSelf()}  {@link
android.content.Context#stopService stopService()}
</p>

<p>{@link android.app.Service#onBind onBind()}
<em>  </em>{@link android.app.Service#onStartCommand onStartCommand()}


</p>

<p><a href="#Lifecycle"></a>

</p>
</div>
</div>

<p>{@link android.content.Context#bindService
bindService()}  {@link
android.content.ServiceConnection} {@link
android.content.Context#bindService bindService()} Android  {@link
android.content.ServiceConnection}  {@link
android.content.ServiceConnection#onServiceConnected onServiceConnected()}  {@link android.os.IBinder}


</p>

<p>1  {@link android.app.Service#onBind onBind()} {@link android.os.IBinder}

 {@link android.app.Service#onBind onBind()}  {@link android.os.IBinder}
</p>

<p> {@link android.content.Context#startService startService()}
</p>

<p>{@link android.app.Service#onBind onBind()}
 {@link android.os.IBinder}

</p>


<h2 id="Creating"></h2>

<p>  {@link android.os.IBinder}
 3
</p>

<dl>
  <dt><a href="#Binder">Binder </a></dt>
  <dd>{@link android.os.Binder}  {@link android.app.Service#onBind onBind()}


 {@link android.os.Binder}  {@link android.os.Binder}  {@link android.app.Service}  public


  <p>

</dd>

  <dt><a href="#Messenger"></a></dt>
  <dd>{@link android.os.Messenger}
 {@link
android.os.Message}  {@link android.os.Handler}
 {@link android.os.Handler}  {@link android.os.Messenger}  {@link android.os.IBinder}   {@link
android.os.Message}

 {@link android.os.Messenger}

  <p>IPC{@link
android.os.Messenger}  1
</p>
  </dd>

  <dt>AIDL </dt>
  <dd>AIDLAndroid  IPC {@link android.os.Messenger}  AIDL


{@link android.os.Messenger}  1
AIDL


  <p>AIDL   {@code .aidl}
Android SDK  IPC

</p>
  </dd>
</dl>

  <p class="note"><strong>:</strong> AIDL <strong></strong>

AIDL  AIDL
 AIDL <a href="{@docRoot}guide/components/aidl.html">AIDL</a>

</p>


<h3 id="Binder">Binder </h3>

<p> public  {@link android.os.Binder}

</p>

<p class="note"><strong>:</strong>


</p>

<p></p>
<ol>
  <li> {@link android.os.Binder}
    <ul>
      <li> public </li>
      <li> public  {@link android.app.Service}
</li>
      <li> public
</li>
    </ul>
  <li>{@link android.os.Binder}  {@link
android.app.Service#onBind onBind()}  </li>
  <li>{@link android.os.Binder}  {@link
android.content.ServiceConnection#onServiceConnected onServiceConnected()}
</li>
</ol>

<p class="note"><strong>:</strong>  API


</p>

<p>{@link android.os.Binder}
</p>

<pre>
public class LocalService extends Service {
    // Binder given to clients
    private final IBinder mBinder = new LocalBinder();
    // Random number generator
    private final Random mGenerator = new Random();

    /**
     * Class used for the client Binder.  Because we know this service always
     * runs in the same process as its clients, we don't need to deal with IPC.
     */
    public class LocalBinder extends Binder {
        LocalService getService() {
            // Return this instance of LocalService so clients can call public methods
            return LocalService.this;
        }
    }

    &#64;Override
    public IBinder onBind(Intent intent) {
        return mBinder;
    }

    /** method for clients */
    public int getRandomNumber() {
      return mGenerator.nextInt(100);
    }
}
</pre>

<p>{@code LocalBinder}  {@code LocalService}  {@code getService()}
 public
 {@code getRandomNumber()} </p>

<p>{@code LocalService}  {@code getRandomNumber()}
</p>

<pre>
public class BindingActivity extends Activity {
    LocalService mService;
    boolean mBound = false;

    &#64;Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    &#64;Override
    protected void onStart() {
        super.onStart();
        // Bind to LocalService
        Intent intent = new Intent(this, LocalService.class);
        bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
    }

    &#64;Override
    protected void onStop() {
        super.onStop();
        // Unbind from the service
        if (mBound) {
            unbindService(mConnection);
            mBound = false;
        }
    }

    /** Called when a button is clicked (the button in the layout file attaches to
      * this method with the android:onClick attribute) */
    public void onButtonClick(View v) {
        if (mBound) {
            // Call a method from the LocalService.
            // However, if this call were something that might hang, then this request should
            // occur in a separate thread to avoid slowing down the activity performance.
            int num = mService.getRandomNumber();
            Toast.makeText(this, "number: " + num, Toast.LENGTH_SHORT).show();
        }
    }

    /** Defines callbacks for service binding, passed to bindService() */
    private ServiceConnection mConnection = new ServiceConnection() {

        &#64;Override
        public void onServiceConnected(ComponentName className,
                IBinder service) {
            // We've bound to LocalService, cast the IBinder and get LocalService instance
            LocalBinder binder = (LocalBinder) service;
            mService = binder.getService();
            mBound = true;
        }

        &#64;Override
        public void onServiceDisconnected(ComponentName arg0) {
            mBound = false;
        }
    };
}
</pre>

<p>{@link android.content.ServiceConnection}  {@link
android.content.ServiceConnection#onServiceConnected onServiceConnected()}

</p>

<p class="note"><strong>:</strong>
</p>

<p> <a href="{@docRoot}resources/samples/ApiDemos/index.html">ApiDemos</a>  <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LocalService.html">{@code
LocalService.java}</a>  <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LocalServiceActivities.html">{@code
LocalServiceActivities.java}</a> </p>


<h3 id="Messenger"></h3>

<div class="sidebox-wrapper">
<div class="sidebox">
  <h4>AIDL </h4>
  <p>IPC  {@link android.os.Messenger}  AIDL {@link android.os.Messenger}  AIDL


</p>
  <p>{@link
android.os.Messenger}  1 <a href="{@docRoot}guide/components/aidl.html">AIDL</a>
</p>
</div>
</div>

<p> {@link android.os.Messenger}
AIDL IPC
</p>

<p>{@link android.os.Messenger} </p>

<ul>
  <li>{@link android.os.Handler}
</li>
  <li>{@link android.os.Handler}  {@link android.os.Messenger}
{@link android.os.Handler} </li>
  <li>{@link android.os.Messenger}  {@link android.app.Service#onBind onBind()}  {@link android.os.IBinder}
</li>
  <li> {@link android.os.IBinder}  {@link android.os.Handler} {@link android.os.Messenger}  {@link android.os.Message}

</li>
  <li> {@link
android.os.Handler}{@link android.os.Handler#handleMessage
handleMessage()}  {@link android.os.Message} &mdash;</li>
</ul>


<p> {@link android.os.Handler} {@link android.os.Message}

</p>

<p>{@link android.os.Messenger} </p>

<pre>
public class MessengerService extends Service {
    /** Command to the service to display a message */
    static final int MSG_SAY_HELLO = 1;

    /**
     * Handler of incoming messages from clients.
     */
    class IncomingHandler extends Handler {
        &#64;Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MSG_SAY_HELLO:
                    Toast.makeText(getApplicationContext(), "hello!", Toast.LENGTH_SHORT).show();
                    break;
                default:
                    super.handleMessage(msg);
            }
        }
    }

    /**
     * Target we publish for clients to send messages to IncomingHandler.
     */
    final Messenger mMessenger = new Messenger(new IncomingHandler());

    /**
     * When binding to the service, we return an interface to our messenger
     * for sending messages to the service.
     */
    &#64;Override
    public IBinder onBind(Intent intent) {
        Toast.makeText(getApplicationContext(), "binding", Toast.LENGTH_SHORT).show();
        return mMessenger.getBinder();
    }
}
</pre>

<p>{@link android.os.Handler}  {@link android.os.Handler#handleMessage handleMessage()}  {@link android.os.Message} {@link android.os.Message#what}

</p>

<p> {@link
android.os.IBinder}  {@link android.os.Messenger} {@link
android.os.Messenger#send send()}  {@code MSG_SAY_HELLO}
</p>

<pre>
public class ActivityMessenger extends Activity {
    /** Messenger for communicating with the service. */
    Messenger mService = null;

    /** Flag indicating whether we have called bind on the service. */
    boolean mBound;

    /**
     * Class for interacting with the main interface of the service.
     */
    private ServiceConnection mConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className, IBinder service) {
            // This is called when the connection with the service has been
            // established, giving us the object we can use to
            // interact with the service.  We are communicating with the
            // service using a Messenger, so here we get a client-side
            // representation of that from the raw IBinder object.
            mService = new Messenger(service);
            mBound = true;
        }

        public void onServiceDisconnected(ComponentName className) {
            // This is called when the connection with the service has been
            // unexpectedly disconnected -- that is, its process crashed.
            mService = null;
            mBound = false;
        }
    };

    public void sayHello(View v) {
        if (!mBound) return;
        // Create and send a message to the service, using a supported 'what' value
        Message msg = Message.obtain(null, MessengerService.MSG_SAY_HELLO, 0, 0);
        try {
            mService.send(msg);
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }

    &#64;Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    &#64;Override
    protected void onStart() {
        super.onStart();
        // Bind to the service
        bindService(new Intent(this, MessengerService.class), mConnection,
            Context.BIND_AUTO_CREATE);
    }

    &#64;Override
    protected void onStop() {
        super.onStop();
        // Unbind from the service
        if (mBound) {
            unbindService(mConnection);
            mBound = false;
        }
    }
}
</pre>

<p> {@link android.os.Messenger}
 {@link android.content.ServiceConnection#onServiceConnected
onServiceConnected()} {@link android.os.Messenger#send send()}  {@link android.os.Message#replyTo} {@link android.os.Messenger}  {@link android.os.Message}


</p>

<p><a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/MessengerService.html">{@code
MessengerService.java}</a> <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/MessengerServiceActivities.html">{@code
MessengerServiceActivities.java}</a></p>


<h2 id="Binding"></h2>

<p>{@link android.content.Context#bindService bindService()}
 Android  {@link android.app.Service#onBind
onBind()}  {@link android.os.IBinder}
</p>

<p>{@link android.content.Context#bindService
bindService()} {@link android.os.IBinder} <em></em>
{@link android.os.IBinder}  {@link
android.content.ServiceConnection}  {@link android.content.Context#bindService
bindService()} {@link android.content.ServiceConnection}  {@link android.os.IBinder}
</p>

<p class="note"><strong>:</strong>   <strong></strong>
&mdash;</p>

<p> </p>
<ol>
  <li>{@link android.content.ServiceConnection}
    <p> 2  </p>
    <dl>
      <dt>{@link android.content.ServiceConnection#onServiceConnected onServiceConnected()}</dt>
        <dd> {@link android.app.Service#onBind onBind()}  {@link android.os.IBinder}
</dd>
      <dt>{@link android.content.ServiceConnection#onServiceDisconnected
onServiceDisconnected()}</dt>
        <dd>Android
<em></em>
</dd>
    </dl>
  </li>
  <li>{@link
android.content.Context#bindService bindService()} {@link
android.content.ServiceConnection}  </li>
  <li> {@link android.content.ServiceConnection#onServiceConnected
onServiceConnected()}
</li>
  <li>{@link
android.content.Context#unbindService unbindService()}
    <p>


</p>
  </li>
</ol>

<p> <a href="#Binder"> Binder </a> {@link android.os.IBinder}  {@code LocalService} {@code
LocalService}

</p>

<pre>
LocalService mService;
private ServiceConnection mConnection = new ServiceConnection() {
    // Called when the connection with the service is established
    public void onServiceConnected(ComponentName className, IBinder service) {
        // Because we have bound to an explicit
        // service that is running in our own process, we can
        // cast its IBinder to a concrete class and directly access it.
        LocalBinder binder = (LocalBinder) service;
        mService = binder.getService();
        mBound = true;
    }

    // Called when the connection with the service disconnects unexpectedly
    public void onServiceDisconnected(ComponentName className) {
        Log.e(TAG, "onServiceDisconnected");
        mBound = false;
    }
};
</pre>

<p> {@link android.content.ServiceConnection}  {@link android.content.Context#bindService bindService()}
</p>

<pre>
Intent intent = new Intent(this, LocalService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
</pre>

<ul>
  <li>{@link android.content.Context#bindService bindService()}  {@link android.content.Intent}

</li>
<li>2  {@link android.content.ServiceConnection} </li>
<li>3  {@link
android.content.Context#BIND_AUTO_CREATE} {@link android.content.Context#BIND_DEBUG_UNBIND}  {@link android.content.Context#BIND_NOT_FOREGROUND}  {@code 0}

</li>
</ul>


<h3></h3>

<p></p>
<ul>
  <li> {@link android.os.DeadObjectException}
 </li>
  <li> </li>
  <li>

    <ul>
      <li>
{@link android.app.Activity#onStart onStart()} {@link
android.app.Activity#onStop onStop()} </li>
      <li>{@link android.app.Activity#onCreate onCreate()} {@link android.app.Activity#onDestroy onDestroy()}


</li>
    </ul>
    <p class="note"><strong>:</strong>  {@link android.app.Activity#onResume onResume()}  {@link
android.app.Activity#onPause onPause()} <strong></strong>

 2


<a href="{@docRoot}guide/components/activities.html#CoordinatingActivities">Activities</a>

</p>
</ul>

<p>  <a href="{@docRoot}resources/samples/ApiDemos/index.html">ApiDemos</a>  <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/RemoteService.html">{@code
RemoteService.java}</a> </p>


<h2 id="Lifecycle"></h2>

<p>Android {@link android.app.Service#onStartCommand onStartCommand()}
 Android

&mdash;</p>

<p>{@link android.app.Service#onStartCommand
onStartCommand()}   <em></em>
 {@link android.app.Service#stopSelf()}  {@link
android.content.Context#stopService stopService()}

</p>

<p> {@link android.app.Service#onUnbind onUnbind()}  {@link android.app.Service#onRebind
onRebind()} {@code true} {@link
android.app.Service#onBind onBind()} {@link android.app.Service#onRebind
onRebind()}  void  {@link android.content.ServiceConnection#onServiceConnected onServiceConnected()}  {@link android.os.IBinder}  1


</p>


<img src="{@docRoot}images/fundamentals/service_binding_tree_lifecycle.png" alt="" />
<p class="img-caption"><strong> 1.</strong>
</p>


<p><a href="{@docRoot}guide/components/services.html#Lifecycle"></a></p>