Android GPS应用程式无法运作

Question

i have tryed to make my own app and to use google maps. I want it to set the center of the map on my curent gps position, but when i have a gps lock on my phone i will just go to these coordinates (0,0) I dont know where i went wrong. Thanks everybody :D

import android.content.Context;
import android.location.Location;
import android.location.LocationListener; 
import android.location.LocationManager;
import android.os.Bundle;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;


public class Courses extends MapActivity {

MapView map;


@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.courses);       
    MapView map = (MapView) findViewById (R.id.MapView);
    map.setBuiltInZoomControls(true);
    map.setSatellite(true);
    final MapController control = map.getController();


    LocationManager manager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

    LocationListener listener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            // TODO Auto-generated method stub
            control.setCenter(new GeoPoint((int)location.getLatitude(),(int)location.getLongitude()));              
            control.setZoom(19);
        }

        @Override
        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub

        }

    };


manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, listener);

}


@Override
protected boolean isRouteDisplayed() {
    // TODO Auto-generated method stub
    return false;
}

} `

Answer 1

The first issue I see here is, that location.getLatitude() and location.getLongitude() return float , which have to be multiplied with 1E6 and then casted as an int to be acceptible for GeoPoint . This also explains why you have coordinates of approximately 0,0

I would suggest replacing your control.setCenter(new GeoPoint((int)location.getLatitude(),(int)location.getLongitude())); with control.setCenter(new GeoPoint((int)(location.getLatitude() * 1E6),(int)(location.getLongitude() * 1E6)));

Try that, it should work then.