Android 位置监听器不工作

Question

我想获取当前设备位置并使用以下命令打开 Google map :

  if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        LocationListener locationListener = new MyLocationListener();
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 10, locationListener);


    } else {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, MY_LOCATION_REQUEST_CODE);
    }




private class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location loc) {

        longitude = loc.getLongitude();
        latitude = loc.getLatitude();

        Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("http://maps.google.com/maps?saddr=" + latitude + "," + longitude + "&daddr=55.877526, 26.533898"));
        startActivity(intent);
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

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

但这段代码不起作用:由于某些原因，监听器被忽略了。

为什么以及如何解决？

Answer 1

"Why..."

因为 requestLocationUpdates() 是一个异步操作，结果(位置)在 onLocationChanged() 回调中返回。该位置无法立即使用。

"...and how to fix it ?"

将您的 Google map Intent 代码移至此处:

@Override
public void onLocationChanged(Location loc) {

    longitude = loc.getLongitude();
    latitude = loc.getLatitude();

    Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("http://maps.google.com/maps?saddr=" + latitude + "," + longitude + "&daddr=55.877526, 26.533898"));
    startActivity(intent);

}