Android: ProgressDialog does not show up

Android ProgressDialog can be used like iOS ActivityIndicator to show the app is blocked on some time-consuming work.

You cannot just show a ProgressDialog and then busy waiting a flag. If so the dialog will not show up. You need to busy wait in another thread.

Example:

final ProgressDialog dialog = ProgressDialog.show(

          MyActivity.this, "",

          "Loading. Please wait...", true);

new Thread(new Runnable() {

  public void run() {

    while (!isWorkDone)

      Thread.yield();

    dialog.dismiss();

  }

}).start();