我的工作围绕创建将在其自身的进程中运行后台服务。这应该让我听，如果设备的位置发生了变化。我应该能够改变标准像通知用户界面之前，移动的距离。

I am working around creating a background service that will run in its own process. It should allow me to listen if the device location has changed. I should be able to change criteria like the distance moved before notifying the UI.

我怎么能这样做？我服务的一个小的知识和 LocationListener的的实施。周围的净任何教程将AP preciated。

How can I do the same? I have a little knowledge of service and LocationListener implementations. Any tutorials around the net would be appreciated.

我得到了一个back-link从堆栈溢出，但我不明白太多。

I got one back-link from stack overflow, but I didn't understand much of it.

推荐答案

首先，你需要创建一个服务。在该服务，创建一个类扩展 LocationListener的。为此，请使用以下code 服务的片断：

First you need to create a Service. In that Service, create a class extending LocationListener. For this, use the following code snippet of Service:

public class LocationService extends Service 
{
       public static final String BROADCAST_ACTION = "Hello World";
       private static final int TWO_MINUTES = 1000 * 60 * 2;
       public LocationManager locationManager;
       public MyLocationListener listener;
       public Location previousBestLocation = null;

       Intent intent;
       int counter = 0;

    @Override
    public void onCreate() 
    {
        super.onCreate();
        intent = new Intent(BROADCAST_ACTION);      
    }

    @Override
    public void onStart(Intent intent, int startId) 
    {      
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        listener = new MyLocationListener();        
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 4000, 0, listener);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 4000, 0, listener);
    }

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

    protected boolean isBetterLocation(Location location, Location currentBestLocation) {
        if (currentBestLocation == null) {
            // A new location is always better than no location
            return true;
        }

        // Check whether the new location fix is newer or older
        long timeDelta = location.getTime() - currentBestLocation.getTime();
        boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
        boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
        boolean isNewer = timeDelta > 0;

        // If it's been more than two minutes since the current location, use the new location
        // because the user has likely moved
        if (isSignificantlyNewer) {
            return true;
        // If the new location is more than two minutes older, it must be worse
        } else if (isSignificantlyOlder) {
            return false;
        }

        // Check whether the new location fix is more or less accurate
        int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
        boolean isLessAccurate = accuracyDelta > 0;
        boolean isMoreAccurate = accuracyDelta < 0;
        boolean isSignificantlyLessAccurate = accuracyDelta > 200;

        // Check if the old and new location are from the same provider
        boolean isFromSameProvider = isSameProvider(location.getProvider(),
                currentBestLocation.getProvider());

        // Determine location quality using a combination of timeliness and accuracy
        if (isMoreAccurate) {
            return true;
        } else if (isNewer && !isLessAccurate) {
            return true;
        } else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
            return true;
        }
        return false;
    }



/** Checks whether two providers are the same */
    private boolean isSameProvider(String provider1, String provider2) {
        if (provider1 == null) {
          return provider2 == null;
        }
        return provider1.equals(provider2);
    }



@Override
    public void onDestroy() {       
       // handler.removeCallbacks(sendUpdatesToUI);     
        super.onDestroy();
        Log.v("STOP_SERVICE", "DONE");
        locationManager.removeUpdates(listener);        
    }   

    public static Thread performOnBackgroundThread(final Runnable runnable) {
        final Thread t = new Thread() {
            @Override
            public void run() {
                try {
                    runnable.run();
                } finally {

                }
            }
        };
        t.start();
        return t;
    }




public class MyLocationListener implements LocationListener
    {

        public void onLocationChanged(final Location loc)
        {
            Log.i("**************************************", "Location changed");
            if(isBetterLocation(loc, previousBestLocation)) {
                loc.getLatitude();
                loc.getLongitude();             
                intent.putExtra("Latitude", loc.getLatitude());
                intent.putExtra("Longitude", loc.getLongitude());     
                intent.putExtra("Provider", loc.getProvider());                 
                sendBroadcast(intent);          

            }                               
        }

        public void onProviderDisabled(String provider)
        {
            Toast.makeText( getApplicationContext(), "Gps Disabled", Toast.LENGTH_SHORT ).show();
        }


        public void onProviderEnabled(String provider)
        {
            Toast.makeText( getApplicationContext(), "Gps Enabled", Toast.LENGTH_SHORT).show();
        }


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

        }

    }
}

将此服务项目中的任何地方，你想要的方式！ :)

Add this Service any where in your project, the way you want! :)