我继续在Pro Android 2的这个服务示例（第304页）上前进，同样，Service示例包含两个类：MainActivity.java和BackgroundService.java，如下所示。我的最新障碍是获取并使用对Service实例的引用来成功地将其传递给处理程序。
从网络搜索中我发现了一种丑陋的方式将处理程序传递给一个不起作用的Service实例。我很感激在这个过程的下一步帮助 - 使它工作。请查看我在该文档下面的注释和代码，尝试将处理程序传递给绑定按钮（bindBtn）中的Service实例。
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.d(TAG, "starting service");
Button bindBtn = (Button)findViewById(R.id.bindBtn);
bindBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
Intent backgroundService = new Intent(MainActivity.this, com.marie.mainactivity.BackgroundService.class);
startService(backgroundService);
// wait until BackgroundService has started
while (BackgroundService.getInstance() == null);
// get instance of BackgroundService
BackgroundService sInstance = BackgroundService.getInstance();
// now finally pass the handler to the Service
sInstance.setHandler(handler);
}
});
Button unbindBtn = (Button)findViewById(R.id.unbindBtn);
unbindBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
stopService(new Intent(MainActivity.this, BackgroundService.class));
}
});
}
}
// The handler to be passed to the Service
private final Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
String msgObj = (String) msg.obj;
int arg1 = msg.arg1;
int arg2 = msg.arg2;
int what = msg.what;
Log.i("handleMessge", "msgObj: " + msgObj + ", " + "arg1: " + arg1 + ", " + "arg2: " + arg2 + ", " + "what: " + what);
}
};
现在是BackgroundService：
public class BackgroundService extends Service {
private NotificationManager notificationMgr;
private Handler mHandler;
private static Service sInstance = null;
@Override
public void onCreate() {
super.onCreate();
notificationMgr = NotificationManager)getSystemService(NOTIFICATION_SERVICE);
displayNotificationMessage("starting Background Service");
Thread thr = new Thread(null, new ServiceWorker(), "BackgroundService");
thr.start();
}
class ServiceWorker implements Runnable
{
public void run() {
//Use the handler to send a message
Message msg = new Message();
msg.obj = "msg obj";
msg.arg1 = 1;
msg.arg2 = 2;
msg.what = 3;
mHandler.sendMessage(msg);
//stop when done
BackgroundService.this.stopSelf();
}
}
@Override
public void onDestroy()
{
displayNotificationMessage("stopping Background Service");
super.onDestroy();
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
private void displayNotificationMessage(String message)
{
Notification notification = new Notification(R.drawable.note, message, System.currentTimeMillis());
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
notification.setLatestEventInfo(this, "Background Service", message, contentIntent);
notificationMgr.notify(R.id.app_notification_id, notification);
}
}
我的目标是在使用绑定按钮（bindBtn）绑定到服务器之后将处理程序传递给服务，并向处理程序发送消息。但我得到一个ANR：ERROR / ActivityManager（96）：com.marie.mainactivity中的ANR。很明显，这似乎是将处理程序传递给Service的错误方法，因为它不起作用。
我正试图在下面发布ANR的Logcat：
D/MainActivity(24622): starting service
I/ActivityManager( 96): Displayed com.marie.mainactivity/.MainActivity: +434ms
D/dalvikvm(23879): GC_EXPLICIT freed 5K, 50% free 2740K/5379K, external 1625K/2137K, paused 79ms
D/dalvikvm(18736): GC_EXPLICIT freed 28K, 49% free 2793K/5379K, external 1625K/2137K, paused 740ms
D/dalvikvm(18551): GC_EXPLICIT freed 32K, 49% free 2967K/5767K, external 1625K/2137K, paused 583ms
D/dalvikvm( 192): GC_EXPLICIT freed 42K, 53% free 3950K/8327K, external 12167K/12379K, paused 1000ms
W/ActivityManager( 96): Timeout executing service: ServiceRecord{4078d160 com.marie.mainactivity/.BackgroundService}
I/Process ( 96): Sending signal. PID: 24622 SIG: 3
I/dalvikvm(24622): threadid=4: reacting to signal 3
I/dalvikvm(24622): Wrote stack traces to '/data/anr/traces.txt'
I/Process ( 96): Sending signal. PID: 96 SIG: 3
I/dalvikvm( 96): threadid=4: reacting to signal 3
I/dalvikvm( 96): Wrote stack traces to '/data/anr/traces.txt'
I/Process ( 96): Sending signal. PID: 184 SIG: 3
I/dalvikvm( 184): threadid=4: reacting to signal 3
I/dalvikvm( 184): Wrote stack traces to '/data/anr/traces.txt'
I/Process ( 96): Sending signal. PID: 158 SIG: 3
I/dalvikvm( 158): threadid=4: reacting to signal 3
I/dalvikvm( 158): Wrote stack traces to '/data/anr/traces.txt'
D/dalvikvm( 96): GC_EXPLICIT freed 1045K, 41% free 6408K/10759K, external 2855K/3554K, paused 126ms
E/ActivityManager( 96): ANR in com.marie.mainactivity
E/ActivityManager( 96): Reason: Executing service com.marie.mainactivity/.BackgroundService
E/ActivityManager( 96): Load: 2.86 / 2.27 / 1.69
E/ActivityManager( 96): CPU usage from 20840ms to 0ms ago:
E/ActivityManager( 96): 93% 24622/com.marie.mainactivity: 93% user + 0% kernel / faults: 536 minor
E/ActivityManager( 96): 1.4% 73/akmd: 0% user + 1.4% kernel
E/ActivityManager( 96): 0.5% 96/system_server: 0.2% user + 0.2% kernel / faults: 9 minor
E/ActivityManager( 96): 0.1% 23879/com.google.android.apps.uploader: 0.1% user + 0% kernel / faults: 49 minor
E/ActivityManager( 96): 0.1% 192/com.android.launcher: 0.1% user + 0% kernel / faults: 69 minor
E/ActivityManager( 96): 0.1% 18551/android.process.acore: 0.1% user + 0% kernel / faults: 54 minor
E/ActivityManager( 96): 0.1% 18736/android.process.media: 0.1% user + 0% kernel / faults: 49 minor
E/ActivityManager( 96): 0% 158/com.android.systemui: 0% user + 0% kernel
E/ActivityManager( 96): 0% 5/events/0: 0% user + 0% kernel
E/ActivityManager( 96): 0% 48/synaptics_wq: 0% user + 0% kernel
E/ActivityManager( 96): 0% 56/ds2784-battery: 0% user + 0% kernel
E/ActivityManager( 96): 96% TOTAL: 96% user + 0.3% kernel
E/ActivityManager( 96): CPU usage from 378ms to 893ms later:
E/ActivityManager( 96): 94% 24622/com.marie.mainactivity: 94% user + 0% kernel
E/ActivityManager( 96): 94% 24622/ie.mainactivity: 94% user + 0% kernel
E/ActivityManager( 96): 3.8% 96/system_server: 1.9% user + 1.9% kernel
E/ActivityManager( 96): 3.8% 115/ActivityManager: 1.9% user + 1.9% kernel
E/ActivityManager( 96): 1.3% 73/akmd: 0% user + 1.3% kernel
E/ActivityManager( 96): 1.3% 24209/akmd: 0% user + 1.3% kernel
E/ActivityManager( 96): 100% TOTAL: 98% user + 1.9% kernel
I/Process ( 96): Sending signal. PID: 24622 SIG: 9
W/ActivityManager( 96): Force finishing activity com.marie.mainactivity/.MainActivity
I/ActivityManager( 96): Killing com.marie.mainactivity (pid=24622): user's request
I/ActivityManager( 96): Process com.marie.mainactivity (pid 24622) has died.
W/ActivityManager( 96): Service crashed 2 times, stopping: ServiceRecord{4078d160 com.marie.mainactivity/.BackgroundService}
I/WindowManager( 96): WIN DEATH: Window{407b7a70 com.marie.mainactivity/com.marie.mainactivity.MainActivity paused=true}
V/RenderScript_jni( 192): surfaceCreated
V/RenderScript_jni( 192): surfaceChanged
W/InputManagerService( 96): Got RemoteException sending setActive(false) notification to pid 24622 uid 10081
I/ActivityManager( 96): Start proc com.amazon.mp3 for service com.amazon.mp3/.service.DownloadService: pid=24632 uid=10055 gids={3003, 1015}
I/ActivityThread(24632): Pub com.amazon.mp3.client.SearchSuggestionProvider: com.amazon.mp3.client.SearchSuggestionProvider
D/Configuration(24632): active site = local
D/FREESPACE(24632): Bytes to fill: 107900928
D/Configuration(24632): active site = remote
I/Gmail (24587): calculateUnknownSyncRationalesAndPurgeInBackground: queueing
I/Gmail (24587): calculateUnknownSyncRationalesAndPurgeInBackground: running
I/Gmail (24587): MainSyncRequestProto: lowestBkwdConvoId: 0, highestHandledServerOp: 687539, normalSync: true
D/dalvikvm(24587): GC_CONCURRENT freed 1165K, 54% free 3133K/6727K, external 1625K/2137K, paused 3ms+4ms
D/dalvikvm(24587): GC_CONCURRENT freed 617K, 55% free 3081K/6727K, external 1625K/2137K, paused 11ms+2ms
D/dalvikvm(24587): GC_EXPLICIT freed 160K, 55% free 3083K/6727K, external 1625K/2137K, paused 54ms
I/Gmail (24587): MainSyncRequestProto: lowestBkwdConvoId: 0, highestHandledServerOp: 687616, normalSync: true
D/Gmail (24587): Inserting message 1371513932623117837. synced=true
D/dalvikvm(24587): GC_EXPLICIT freed 123K, 54% free 3127K/6727K, external 1625K/2137K, paused 63ms
I/Gmail (24587): MainSyncRequestProto: lowestBkwdConvoId: 0, highestHandledServerOp: 687618, normalSync: true
I/Gmail (24587): Sending notification intent: Intent { act=android.intent.action.PROVIDER_CHANGED dat=content://gmail-ls/unread/^i (has extras) }
I/AudioService( 96): AudioFocus requestAudioFocus() from android.media.AudioManager@4074e410
W/AudioFlinger( 68): write blocked for 167 msecs, 27 delayed writes, thread 0xea00
I/AudioService( 96): AudioFocus abandonAudioFocus() from android.media.AudioManager@4074e410
D/AudioHardwareQSD( 68): AudioHardware pcm playback is going to standby.
D/dalvikvm(24587): GC_EXPLICIT freed 88K, 54% free 3138K/6727K, external 1625K/2137K, paused 98ms
I/ActivityManager( 96): Start proc org.my_pod.mypod for service org.my_pod.mypod/net.robmunro.mypod.UpdateFeedsService: pid=24654 uid=10080 gids={3003, 1015}
D/dalvikvm( 67): GC_EXPLICIT freed 11K, 50% free 2717K/5379K, external 1625K/2137K, paused 68ms
D/dalvikvm( 67): GC_EXPLICIT freed <1K, 50% free 2717K/5379K, external 1625K/2137K, paused 63ms
I/ActivityThread(24654): Pub org.my_pod.mypod: net.robmunro.mypod.util.MyPodContentProvider
D/dalvikvm( 67): GC_EXPLICIT freed <1K, 50% free 2717K/5379K, external 1625K/2137K, paused 74ms
任何关于创建服务实例的错误的建议，所以我可以将它传递给处理程序，这将非常感谢。
答案 0 :(得分：1)
我建议将Messenger传递给该服务，然后使用它将Message发送到Handler。 Here is a sample application证明了这一点。