如何创建不断检查 GPS 状态的后台服务?

How to create background service which constantly check GPS status?

对于我的应用程序,始终需要 GPS。 如果 GPS 关闭,那么我想向用户显示一条提示消息以打开 GPS。

我应该如何使用后台服务来执行此任务?

服务,我从 Whosebug 得到参考

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);
        }
    }
}

清单

<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>