我在为指南针应用设置目标位置时遇到问题。基本上它指向一个设定的目的地（而不是北方）。但是，每当我尝试执行 destinationObj.setLatittude() 或 setLongitutde() 时，我已经计算出了所有的数学运算，应用程序强制关闭。
奇怪的是，如果我将destinationObj set.Lat/Long 放在位置监听器中，它会覆盖GPS 位置，就好像应用程序只能识别一个位置而不是两个。
请提供任何指导。
谢谢，
这是我的代码：
import android.app.Activity;
...
public class CompassActivity extends Activity {
LocationManager locationManager;
Location LocationObj, destinationObj;
private SensorEventListener mListener = new SensorEventListener() {
public void onSensorChanged( SensorEvent event ) {
if ( LocationObj == null ) return;
...bearing calculation...
float bearing = LocationObj.bearingTo(destinationObj);
rotateImageView( needle, R.drawable.needle, direction);
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
needle = (ImageView)findViewById(R.id.needle);
log = (TextView)findViewById(R.id.log);
lat = (TextView)findViewById(R.id.lat);
**destinationObj.setLatitude(20);
destinationObj.setLongitude(30);**
LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
LocationObj = location;
log.setText(Double.toString(location.getLongitude()));
lat.setText(Double.toString(location.getLatitude()));
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
mlocManager.requestLocationUpdates( LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
mSensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
}
private void rotateImageView( ImageView imageView, int drawable, float rotate ) {
...image rotation...
}
@Override
protected void onResume()
{
super.onResume();
mSensorManager.registerListener(mListener, mSensor,
SensorManager.SENSOR_DELAY_GAME);
}
@Override
protected void onStop()
{
mSensorManager.unregisterListener(mListener);
super.onStop();
}
}