Problem while implement location listener in andro

问题:

I am working on a Widget which will get the Current GPS location and pass this value to remote PHP page to get the Information and display it in the Widget. This is what I am trying to do.

I am facing problem while implementing Location Listener for appWidget. It is not updating with the Current Location and It is showing the initial widget i.e "Loading Widget"(Here I put this text)

Can we implement Location Listener for AppWidgetProvider?
Or
Can you suggest me the possible solution for getting GPS location in App Widget?

I placed all necessary permissions in Manifest file.
Here is my code snippet:

public class test extends AppWidgetProvider {
static LocationManager locMan;
static Location curLocation;
static Boolean locationChanged;

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,int[] appWidgetIds) {
    // To prevent any ANR timeouts, we perform the update in a service
    context.startService(new Intent(context, UpdateService.class));
}

public static class UpdateService extends Service {
    // GPS Listener Class
    LocationListener gpsListener = new LocationListener() {
        public void onLocationChanged(Location location) {
            // Log.w("GPS", "Started");
            if (curLocation == null) {
                curLocation = location;
                locationChanged = true;
            }

            if (curLocation.getLatitude() == location.getLatitude() && curLocation.getLongitude() == location.getLongitude())
                locationChanged = false;
            else
                locationChanged = true;

            curLocation = location;

            if (locationChanged) 
                locMan.removeUpdates(gpsListener);

        }

        public void onProviderDisabled(String provider) {

        }

        public void onProviderEnabled(String provider) {
            // Log.w("GPS", "Location changed", null);
        }

        public void onStatusChanged(String provider, int status,
                Bundle extras) {
            if (status == 0)// UnAvailable
            {

            } else if (status == 1)// Trying to Connect
            {

            } else if (status == 2) {// Available

            }
        }

    };

    // In service start method, I am registering for GPS Updates
    @Override
    public void onStart(Intent intent, int startId) {

        locMan = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        if (locMan.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
            locMan.requestLocationUpdates(LocationManager.GPS_PROVIDER,20000, 1, gpsListener);
        } else {
            this.startActivity(new Intent("android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS"));
        }

        if (curLocation != null) {
            double lat = curLocation.getLatitude();
            double lng = curLocation.getLongitude();
            Toast.makeText(getBaseContext(),"Lat : " + String.valueOf(lat) + "\n Long : "+ String.valueOf(lng), Toast.LENGTH_LONG).show();

        }
        // Build the widget update for today
        RemoteViews updateViews = buildUpdate(this);

        // Push update for this widget to the home screen
        ComponentName thisWidget = new ComponentName(this,InKakinadaWidget.class);
        AppWidgetManager manager = AppWidgetManager.getInstance(this);
        manager.updateAppWidget(thisWidget, updateViews);

    }

    public RemoteViews buildUpdate(Context context) {
        // Here I am updating the remoteview
        return updateViews;
    }

    @Override
    public IBinder onBind(Intent intent) {
        // We don't need to bind to this service
        return null;
    }

}
}

Thanks in Advance...

With Regards, Raghavendra K.

回答1:

Are you having this problem in the emulator or on a device? If on the emulator, make sure you use DDMS to set a GPS location. But the easiest thing to do might be to run your code on a device to see if you get GPS updates that way.

回答2:

The problem I see is that you are trying to check curLocation in onStart() right after calling requestLocationUpdates(). LocationManager.requestLocationUpdates() is asynchronous, meaning your LocationListener will not get called back until after onStart() has returned. Have your LocationListener update the UI after it receives the location, don't try and do it in onStart.