如何創建不斷檢查GPS狀態的後臺服務？

Question

對於我的應用程序不斷需要GPS。 如果GPS關閉，那麼我想向用戶顯示一條提示信息來打開GPS。

我應該如何使用後臺服務來執行此任務？

Answer 1

服務，我從計算器

public class MyService extends Service 
{ 
    private static final String TAG = "BOOMBOOMTESTGPS"; 
    private LocationManager mLocationManager = null; 
    private static final int LOCATION_INTERVAL = 1000; 
    private static final float LOCATION_DISTANCE = 10f; 

    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); 
      mLastLocation.set(location); 
     } 

     @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) 
    }; 

    @Override 
    public IBinder onBind(Intent arg0) 
    { 
     return null; 
    } 

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

    @Override 
    public void 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()); 
     } 
    } 

    @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); 
     } 
    } 
} 

清單參考

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 
<application 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" > 
    <activity android:label="@string/app_name" android:name=".LocationCheckerActivity" > 
     <intent-filter > 
      <action android:name="android.intent.action.MAIN" /> 
      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 
    <service android:name=".MyService" android:process=":my_service" /> 
</application>