服務中的LocationManager

Question

服務中可以使用getSystemService嗎？我的服務類：

private LocationManager locationManager; 
private LocationListener locationListener; 

IBinder mBinder = new LocalBinder();  

public interface interfaceLocationService {  
     public Location currentBestLocation = null; 
     public void startListenLocation(); 
     public void stopListenLocation(); 
     public Location getUserLocation(); 
} 

@Override 
public IBinder onBind(Intent intent) { 
    return mBinder; 
} 

public class LocalBinder extends Binder implements interfaceLocationService{ 

    public void StopListenLocation(){ 
     locationManager.removeUpdates(locationListener); 
     locationListener = null; 
     stopSelf(); 
    } 

    public void startListenLocation() 
    { 
     locationListener = new LocationListener() { 

      public void onStatusChanged(String provider, int status, Bundle extras) {  
       switch (status) { 

       // Provider out of service 
       case LocationProvider.OUT_OF_SERVICE: 
        Log.v(TAG, "Provider status changed: Out of Service"); 
        break; 

       // Provider temporarily unavailable 
       case LocationProvider.TEMPORARILY_UNAVAILABLE: 
        Log.v(TAG, "Provider status changed: Temporarily Unavailable"); 
        break; 

       // Provider available again 
       case LocationProvider.AVAILABLE: 
        Log.v(TAG, "Provider status changed: Available"); 
        break; 
       } 
      }  

      public void onProviderEnabled(String provider) {  
       Log.v(TAG, "Provider enabled"); 
      } 

      public void onProviderDisabled(String provider) {  
       Log.v(TAG, "Provider disabled"); 

       // Settings brought up to connect 
       Intent intent = new Intent(
         android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS); 
       startActivity(intent); 
      } 

      public void onLocationChanged(Location location) {     
       Log.v(TAG, "Location Changed"); 
       if (isBetterLocation(location, currentBestLocation)) { 
        currentBestLocation.set(location); 
       } 
      } 
     }; 
     //if I have only one requestLocationUpdates situation is the same 
      locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 
        400, 1, locationListener); 
     } 

    public Location getUserLocation(){ 
     return currentBestLocation; 
    } 

    @Override 
    public void stopListenLocation() { 
     locationManager.removeUpdates(locationListener); 
     locationListener = null; 
     stopSelf(); 
    } 
} 

@Override 
public void onCreate() { 
    // Start thread 
    locationManager = (LocationManager)SendService.this.getSystemService(Context.LOCATION_SERVICE); 
    super.onCreate(); 
    Log.d(TAG, "SendService created"); 
} 

@Override 
public void onDestroy() { 
    // Just destroy thread 
    super.onDestroy(); 
    Log.d(TAG, "SendService destroyed"); 
} 

而且在活動我的代碼啓動該服務：

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    Intent intent = new Intent(this, SendService.class); 
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE); 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
} 

private ServiceConnection mConnection = new ServiceConnection() { 

    public void onServiceConnected(ComponentName className, 
      IBinder service) { 
     mService = (interfaceLocationService) service; 
    } 

    public void onServiceDisconnected(ComponentName arg0) { 
     Log.d("LOG","Service disconnected"); 
     mService.stopListenLocation(); 
    } 
}; 

public void startClicked(View v) { 
    mService.startListenLocation(); 
} 

這個代碼給出了logcat的一個錯誤：

11-12 17:01:02.171: E/AndroidRuntime(2719): FATAL EXCEPTION: main 
11-12 17:01:02.171: E/AndroidRuntime(2719): android.util.AndroidRuntimeException:  Calling startActivity() from outside of an Activity context requires the  FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want? 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.app.ContextImpl.startActivity(ContextImpl.java:657) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.content.ContextWrapper.startActivity(ContextWrapper.java:258) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at com.example.gps.data.SendService$LocalBinder$1.onProviderDisabled(SendService.java:78) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.location.LocationManager$ListenerTransport._handleMessage(LocationManager.java:204) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.location.LocationManager$ListenerTransport.access$000(LocationManager.java:124) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.location.LocationManager$ListenerTransport$1.handleMessage(LocationManager.java:140) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.os.Handler.dispatchMessage(Handler.java:99) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.os.Looper.loop(Looper.java:143) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at android.app.ActivityThread.main(ActivityThread.java:4717) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at java.lang.reflect.Method.invokeNative(Native Method) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at java.lang.reflect.Method.invoke(Method.java:521) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
11-12 17:01:02.171: E/AndroidRuntime(2719):  at dalvik.system.NativeStart.main(Native Method) 

簡單：我能使用LocationManager來在後臺收聽service的位置？如果是，那麼我的錯誤在哪裏？

Answer 1

當然，您可以在服務中使用LocationManager。比如我在後臺服務的onCreate方法這樣做：

public void onCreate() { 
     mLocationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 

     Criteria criteria = new Criteria(); 
     criteria.setAccuracy(Criteria.ACCURACY_COARSE); 
     criteria.setAltitudeRequired(false); 
     criteria.setBearingRequired(false); 
     criteria.setCostAllowed(true); 

     String provider = mLocationManager.getBestProvider(criteria, true); 
     mLocationManager.requestLocationUpdates(provider, LOCATION_UPDATE_INTERVAL_MILLIS, LOCATION_UPDATE_INTERVAL_METERS, this); 

    }