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我有TrackingService組件來跟蹤我的城市中基於Crowdsourcing的巴士位置。 TrackingService在後臺運行，然後將數據傳輸到服務器。我有一個地圖活動來顯示總線的位置，在MainActivity中選擇的用戶（作爲過濾器）。LocalBroadcastManager - 接收器未註冊
當應用程序啓動時，背景TrackingService在MainActivity中啓動。
我在BroadcastReceiver的幫助下，通過下面的代碼告知更新的lcoation的map活動。數據正在被檢索到地圖活動，但我面臨着取消註冊我的bReceiver的問題。我想在應用程序進入後臺或當用戶按下後退按鈕時取消註冊廣播，但我得到以下錯誤：
我該如何解決它？
錯誤：
08-27 22:43:04.594: E/AndroidRuntime(19588): FATAL EXCEPTION: main
08-27 22:43:04.594: E/AndroidRuntime(19588): Process: com.bustracker, PID: 19588
08-27 22:43:04.594: E/AndroidRuntime(19588): java.lang.RuntimeException: Unable to stop activity {com.bustracker/com.bustracker.Map}: java.lang.IllegalArgumentException: Receiver not registered: [email protected]
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4156)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:4219)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ActivityThread.access$1500(ActivityThread.java:177)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1502)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.os.Handler.dispatchMessage(Handler.java:102)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.os.Looper.loop(Looper.java:145)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ActivityThread.main(ActivityThread.java:5944)
08-27 22:43:04.594: E/AndroidRuntime(19588): at java.lang.reflect.Method.invoke(Native Method)
08-27 22:43:04.594: E/AndroidRuntime(19588): at java.lang.reflect.Method.invoke(Method.java:372)
08-27 22:43:04.594: E/AndroidRuntime(19588): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1389)
08-27 22:43:04.594: E/AndroidRuntime(19588): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)
08-27 22:43:04.594: E/AndroidRuntime(19588): Caused by: java.lang.IllegalArgumentException: Receiver not registered: [email protected]
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:822)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:2038)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.content.ContextWrapper.unregisterReceiver(ContextWrapper.java:528)
08-27 22:43:04.594: E/AndroidRuntime(19588): at com.bustracker.Map.onStop(Map.java:418)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1275)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.Activity.performStop(Activity.java:6493)
08-27 22:43:04.594: E/AndroidRuntime(19588): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4151)
08-27 22:43:04.594: E/AndroidRuntime(19588): ... 10 more
TrackingService類：
public class TrackingService extends Service implements
LocationListener {
public double pLong;
public double pLat;
...
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
detectLocation();
return START_STICKY;
}
private void detectLocation() {
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 30 * 1000, 0,
this);
}
@Override
public void onLocationChanged(Location location) {
if (location != null) {
pLong = location.getLongitude();
pLat = location.getLatitude();
Intent intent = new Intent(Map.RECEIVE_latLng);
intent.putExtra("location",location);
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
.....
}
}
地圖活動：
public class Map extends FragmentActivity implements OnMapReadyCallback {
public static final String RECEIVE_latLng = "com.bustracker.RECEIVE_latLng";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
}
@Override
protected void onStart() {
super.onStart();
LocalBroadcastManager bManager = LocalBroadcastManager.getInstance(this);
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(RECEIVE_latLng);
bManager.registerReceiver(bReceiver, intentFilter);
}
private BroadcastReceiver bReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals(RECEIVE_latLng)) {
Location location = intent.getParcelableExtra("location");
double lng = location.getLongitude();
double lat = location.getLatitude();
LatLng ll = new LatLng(lat, lng);
MarkerOptions markerOpt = new MarkerOptions().title("My Location")
.position(ll);
System.out.println("ABC map: "+ lat + " ; " + lng);
myLocatMarker = map.addMarker(markerOpt);
}
}
};
}
@Override
protected void onStop() {
super.onStop();
unregisterReceiver(bReceiver);
}