서비스에 연결되었지만 사용하려고 할 때 실패 함

Question

내 서비스를 사용하려고 할 때 프로그램이 실패하는 문제가 있습니다. 나는이가 그런

startService(new Intent(this, GPSService.class)); 

(메인라는) 다른 활동 : 처음 활동을 시작한다

다음 나는 주요, doBindService을 (전화 상속

protected GPSService gService; 
protected boolean mIsBound = false; 
    protected ServiceConnection mConnection = new ServiceConnection() { 
    @Override 
    public void onServiceConnected(ComponentName className, IBinder service) { 
     GPSServiceBinder binder = (GPSServiceBinder) service; 
     gService = binder.getServerInstance(); 
     mIsBound = true; 
     Toast.makeText(ActionBarActivity.this, "Attached to a process", 
       Toast.LENGTH_SHORT).show(); 
    } 

    @Override 
    public void onServiceDisconnected(ComponentName className) { 
     gService = null; 
     Toast.makeText(ActionBarActivity.this, "Deattachhed from process", 
       Toast.LENGTH_SHORT).show(); 
    } 
}; 

protected void doBindService(Activity act) { 
    getApplication().bindService(new Intent(act, 
      GPSService.class), mConnection, Context.BIND_AUTO_CREATE); 

    mIsBound = true; 
    if(mIsBound) 
     Toast.makeText(ActionBarActivity.this, "connected", 
       Toast.LENGTH_SHORT).show(); 

}; 

)하고, gService를 사용하려고 NullPointer 예외가 발생하면 실패합니다.

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    doBindService(OccupationActivity.this); 
      gService.getLocation(); 

그러나 onServiceConnected()의 토스트가 제대로 작동합니다. 당신이 doBindService()를 호출 할 때이 서비스에 바인딩을 시도하기 때문

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    doBindService(OccupationActivity.this); 
    gService.getLocation(); 

하지만,이 문제가 해결되지 수

public class GPSService extends Service { 
private static final String TAG = "GPS_SERVICE"; 
private LocationManager mLocationManager = null; 
private static final int LOCATION_INTERVAL = 1000; 
private static final float LOCATION_DISTANCE = 10f; 
Location currentLocation; 

private class LocationListener implements android.location.LocationListener{ 

    Location mLastLocation; 

    public LocationListener(String provider) 
    { 
     Log.e(TAG, "LocationListener " + provider); 
     mLastLocation = new Location(provider); 
    } 

    @Override 
    public void onLocationChanged(Location location) 
    { 
     Log.e(TAG, "onLocationChanged: " + location); 
     if (location != null){ 
      mLastLocation.set(location); 
      currentLocation = mLastLocation;     
     } 

    } 

    @Override 
    public void onProviderDisabled(String provider) 
    { 
     Log.e(TAG, "onProviderDisabled: " + provider);    
    } 

    @Override 
    public void onProviderEnabled(String provider) 
    { 
     Log.e(TAG, "onProviderEnabled: " + provider); 
    } 

    @Override 
    public void onStatusChanged(String provider, int status, Bundle extras) 
    { 
     Log.e(TAG, "onStatusChanged: " + provider); 
    } 


} 


LocationListener[] mLocationListeners = new LocationListener[] { 
     new LocationListener(LocationManager.GPS_PROVIDER), 
     new LocationListener(LocationManager.NETWORK_PROVIDER) 
}; 


private IBinder mBinder = new GPSServiceBinder(); 

public class GPSServiceBinder extends Binder { 
    public GPSService getServerInstance() { 
     return GPSService.this; 
    } 
} 

@Override 
public int onStartCommand(Intent intent, int flags, int startId) 
{ 
    Log.e(TAG, "onStartCommand"); 
    super.onStartCommand(intent, flags, startId);  
    return START_STICKY; 
} 

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

int minTime = 60000; 
float minDistance = 15; 

@Override 
public void onCreate() 
{ 
    super.onCreate(); 
    Log.e(TAG, "onCreate"); 
    initializeLocationManager(); 

    try { 
     mLocationManager.requestLocationUpdates(
       LocationManager.NETWORK_PROVIDER, LOCATION_INTERVAL, LOCATION_DISTANCE, 
       mLocationListeners[1]); 
    } catch (java.lang.SecurityException ex) { 
     Log.i(TAG, "fail to request location update, ignore", ex); 
    } catch (IllegalArgumentException ex) { 
     Log.d(TAG, "network provider does not exist, " + ex.getMessage()); 
    } 
    try { 
     mLocationManager.requestLocationUpdates(
       LocationManager.GPS_PROVIDER, LOCATION_INTERVAL, LOCATION_DISTANCE, 
       mLocationListeners[0]); 
    } catch (java.lang.SecurityException ex) { 
     Log.i(TAG, "fail to request location update, ignore", ex); 
    } catch (IllegalArgumentException ex) { 
     Log.d(TAG, "gps provider does not exist " + ex.getMessage()); 
    } 
} 


public Location getLocation() 
{ 
    return currentLocation; 
} 

public boolean getGPSstatus() 
{ 
    if (mLocationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){ 
     return true;  
    }else{ 
     return false; 
    } 

} 



@Override 
public void onDestroy() 
{ 
    Log.e(TAG, "onDestroy"); 
    super.onDestroy(); 
    if (mLocationManager != null) { 
     for (int i = 0; i < mLocationListeners.length; i++) { 
      try { 
       mLocationManager.removeUpdates(mLocationListeners[i]); 
      } catch (Exception ex) { 
       Log.i(TAG, "fail to remove location listners, ignore", ex); 
      } 
     } 
    } 
} 


private void initializeLocationManager() { 
    Log.e(TAG, "initializeLocationManager"); 
    if (mLocationManager == null) { 
     mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE); 
    } 
} 

}

Answer 1

:

이 내 서비스 클래스 나중에 서비스 바인딩을 완료하기 위해 onServiceConnected() 콜백이 발생합니다. 이 콜백은 비동기식이며 주 스레드에서 실행됩니다. 즉, 이 코드에 onCreate()을 반환하면 gService 변수를 즉시 사용하지만 onServiceConnected()에 대한 호출이 아직 발생하지 않았으므로이 변수가 아직 설정되지 않았습니다.

gService.getLocation()으로 전화를 이동하려면 onCreate()에서 onServiceConnected()이 호출 될 때 트리거되는 활동의 다른 방법으로 이동해야합니다.