How to Display a progress bar that displays over the fade screen overlapping the previous activity

I am trying to create an ac开发者_如何学编程tivity. I have made some controls in that activity. Suppose, I click on some control(e.g Button), then a fade screen display that overlaps the previous activity and over the fade screen there is a progress bar. when the progress bar is 100% completed, then the fade screens disappear and the next activity displays.

Now my question is, How can I make a fade screen that displays over(overlaps) the previous activity and the fade screen also contains the progress bar?

---

Ther is no need to care about overlapping. Progress Bar is always shown in foreground overlapping the activity containg it.

    import android.app.Activity;
    import android.app.Dialog;
    import android.app.ProgressDialog;
    import android.os.AsyncTask;
    import android.os.Bundle;

    public class ProgressDialogDemo extends Activity {
/** Called when the activity is first created. */
ProgressDialog  dialog;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    dialog = new ProgressDialog(this);
    dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    dialog.setMessage("Loading...");
    dialog.setCancelable(true);



    new Loader().execute();


}

class Loader extends AsyncTask<Object, Object, Object> {

    @Override
    protected Object doInBackground(Object... params) {
        // TODO Auto-generated method stub
        for( int i = 0; i <= 100; i++){

            publishProgress( i );
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub

        super.onPreExecute();
        dialog.show();
    }

    @Override
    protected void onPostExecute(Object result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        dialog.dismiss();
    }

    @Override
    protected void onProgressUpdate(Object... values) {
        // TODO Auto-generated method stub
        super.onProgressUpdate(values);
        dialog.setProgress( ( (Integer)values[0]).intValue() );
    }

}}