android关于获取经纬度的问题

Question

public void bcwens(View s)
{

String dz=Context.LOCATION_SERVICE;
LocationManager jt=(LocationManager) getSystemService(dz);
if (!jt .isProviderEnabled(android.location.LocationManager. GPS_PROVIDER));
String ddz=jt.GPS_PROVIDER;
Location zz=jt.getLastKnownLocation(ddz);
jt.requestLocationUpdates(ddz, 2000, 1, locationListener);

       double z1=zz.getLatitude();//这两句不能运行直接崩了
  double z2=zz.getLongitude();


    String z3=String.valueOf(z1);
  String z4=String.valueOf(z2);  
 jt.removeUpdates(locationListener);
  MainActivity.writeNewsToSql(z3+z4);
}
private final LocationListener locationListener = new LocationListener(){
    @Override
    public void onLocationChanged(Location zz) {
        getLocationInfo(zz);
    }
    @Override
    public void onProviderDisabled(String provider) {
        getLocationInfo(null);
    }
    @Override
    public void onProviderEnabled(String provider) {
        getLocationInfo(null);
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    }
};

Answer 1

原因是location获取的值为空，导致的转换失败，至于为什么获取为空，还请大神来给我解答下