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"> 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>- Activity (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()}
Activity
Activity
</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>
{@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}

</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}

  <p>

</dd>

  <dt><a href="#Messenger"> 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}
</p>
  </dd>

  <dt> AIDL</dt>
  <dd>AIDLAndroid

IPC {@link android.os.Messenger}  AIDL
{@link android.os.Messenger}

AIDL

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

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

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


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

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

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

</p>

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

 {@code getRandomNumber()}</p>

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


<p>{@link android.os.Message}
 {@link android.os.Handler}
</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}  Activity</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.Message}
{@link android.os.Messenger#send send()}  {@link android.os.Message#replyTo}
 {@link android.os.Messenger}</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()} <em></em> {@link android.os.IBinder}
 {@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> Activity&mdash;<strong></strong>
</p>

<p> </p>
<ol>
  <li> {@link android.content.ServiceConnection}
    <p></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> Activity


</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} Intent </li>
<li> {@link android.content.ServiceConnection} </li>
<li> {@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> (bring-up)  (tear-down)

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


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


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

</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()} &mdash;Android

</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()}  {@link
android.app.Service#onBind onBind()}
{@code true}{@link android.app.Service#onRebind
onRebind()}  {@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>