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">  </a></li>
      <li><a href="#Messenger"> </a></li>
    </ol>
  </li>
  <li><a href="#Binding"> </a></li>
  <li><a href="#Lifecycle">    </a></li>
</ol>

<h2>Key </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#onServiceConnected onServiceConnected()} {@link
android.content.ServiceConnection}         {@link android.os.IBinder}
 .</p>

<p>       . ,
{@link android.app.Service#onBind onBind()}   {@link android.os.IBinder}
 .     {@link android.os.IBinder}
    {@link android.app.Service#onBind onBind()}   .</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">  </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"> </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>AIDL(Android Interface Definition Language)
         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>   ,
    AIDL  <strong> </strong>.
      ,        .  AIDL
             . AIDL      ,
<a href="{@docRoot}guide/components/aidl.html">AIDL</a>  .
</p>


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

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

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

 .</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.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()}
 .          .
    {@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}        .
    ,    <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.Message} {@link
android.os.Handler} .  {@link android.os.Handler#handleMessage
handleMessage()}  .</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}     .</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
system  {@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>.</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>      ,
             .

(        ).</p>
  </li>
</ol>

<p> ,
<a href="#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>   {@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>,
        . :
    <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> .

   . ,

     ,     ( )    ( )
      (
<a href="{@docRoot}guide/components/activities.html#CoordinatingActivities"></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    .</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()}
{@code true}    .     ({@link
android.app.Service#onBind onBind()}    ) {@link android.app.Service#onRebind
onRebind()}      . {@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>