Question

我需要创建在AsyncTask并发活动开始时创建的消失对话框。但我试图在onPostExecute（）中插入dialog.dismiss（），但它根本没有显示对话框。

我正在获得GPS纬度和经度，那时我想显示ProgressDialog。并显示，但在活动结束后我无法解雇。

这是编码。

public class SearchActivity extends Activity {

    private ProgressDialog dialog;

    private static String PROVIDER = LocationManager.GPS_PROVIDER;
    private LocationManager locationManager;

    double longitude = 0.0;
    double latitude = 0.0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        Bundle extras = getIntent().getExtras();

        if (extras == null) {
            Toast.makeText(this, "Something Wrong existing....",
                    Toast.LENGTH_SHORT).show();
            finish();
        }

        String utterance = extras.getString("utterance");
        String location = extras.getString("location");

        if (location == null) {
            dialog = ProgressDialog.show(this, "",
                    "Searching your location...", true);
            dialog.setCancelable(true);
            new GPSLocator().execute();

        }else{
            Toast.makeText(getApplicationContext(), "Location is from SpeechRecognizer Activity", Toast.LENGTH_LONG).show();
        }

    }

    public class GPSLocator extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {
            // TODO Auto-generated method stub

            String info = getLocation();

            return info;
        }

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);

            Toast.makeText(getApplicationContext(), result, Toast.LENGTH_LONG).show();

                    dialog.dismiss();
        }

        @Override
        protected void onProgressUpdate(Void... values) {
            // TODO Auto-generated method stub
            super.onProgressUpdate(values);
        }

        public String getLocation() {

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

            Location loc = locationManager.getLastKnownLocation(PROVIDER);

            if (loc == null) {
                return "GPS is not available. Location is null";
            } else {
                latitude = loc.getLatitude();
                longitude = loc.getLongitude();

                return String.valueOf(latitude) + " - "
                        + String.valueOf(longitude);

            }

        }

    }

}

Answer 1

您应该在AsyncTask类中的onPreExecute（）内初始化对话框使用：

if (location == null) {
            dialog = ProgressDialog.show(this, "",
                    "Searching your location...", true);
            dialog.setCancelable(true);}

OnPreExecute顾名思义在所有其他方法之前运行，所以

1）onPreExecute：对话框初始化

2）doinbackground：做你的东西和

3）onPostExecute使用结果并关闭对话框。

价：HTTP：//developer.android.com/reference/android/os/AsyncTask.html

AsyncTask完成后，使Dialog解除

1 个答案: