How to handle screen orientation change when progress dialog and background thread active?

Question

My program does some network activity in a background thread. Before starting, it pops up a progress dialog. The dialog is dismissed on the handler. This all works fine, exc

Answer 1

The trick is to show/dismiss the dialog within AsyncTask during onPreExecute/onPostExecute as usual, though in case of orientation-change create/show a new instance of the dialog in the activity and pass its reference to the task.

public class MainActivity extends Activity {
    private Button mButton;
    private MyTask mTask = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        MyTask task = (MyTask) getLastNonConfigurationInstance();
        if(task != null){
            mTask = task;
            mTask.mContext = this;
            mTask.mDialog = ProgressDialog.show(this, "", "", true);        
        }

        mButton = (Button) findViewById(R.id.button1);
        mButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                mTask = new MyTask(MainActivity.this);
                mTask.execute();
            }
        });
    }


    @Override
    public Object onRetainNonConfigurationInstance() {
        String str = "null";
        if(mTask != null){
            str = mTask.toString();
            mTask.mDialog.dismiss();
        }
        Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
        return mTask;
    }



    private class MyTask extends AsyncTask{
        private ProgressDialog mDialog;
        private MainActivity mContext;


        public MyTask(MainActivity context){
            super();
            mContext = context;
        }


        protected void onPreExecute() {
            mDialog = ProgressDialog.show(MainActivity.this, "", "", true);
        }

        protected void onPostExecute(Void result) {
            mContext.mTask = null;
            mDialog.dismiss();
        }


        @Override
        protected Void doInBackground(Void... params) {
            SystemClock.sleep(5000);
            return null;
        }       
    }
}