如何在安卓系统中更新位置并禁用GPS?

我正在使用以下代码获取GPS位置

它引起了两个问题

1) 当我的位置改变时/我将手机从一个区域移动到另一个区域时,我不会得到更新的gps位置(纬度/经度)

 double MyDeviceLatitude,MyDeviceLongitude;

public void GetGPSLocation()
{

 LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 

                       LocationListener myLocationListener = new CurrentLocationListener(); 

                       locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 30, 30, myLocationListener);

                   Location   currentLocation = locationManager.getLastKnownLocation("gps"); 

if(currentLocation != null)
                       {

                       MyDeviceLatitude = currentLocation.getLatitude();
                       MyDeviceLongitude = currentLocation.getLongitude();
}else
{

 currentLocation = locationManager.getLastKnownLocation("network");
 MyDeviceLatitude = currentLocation.getLatitude();
 MyDeviceLongitude = currentLocation.getLongitude();



}



public class CurrentLocationListener implements LocationListener{

            public void onLocationChanged(Location argLocation) 
            {
                if (argLocation != null) 
                {
                    MyDeviceLatitude = argLocation.getLatitude();
                    MyDeviceLongitude = argLocation.getLongitude();
                }

            }
            public void onProviderDisabled(String provider) {
            }

            public void onProviderEnabled(String provider) {
            }

            public void onStatusChanged(String provider, int status, Bundle arg2) {
            }
            }

}