@Override
  public void onClick(DialogInterface dialog, int which) {
    // will call onCancelListener
    MyApplication.factoryReset(); // (deletes db, clears sharedPrefs etc.)
    Intent i = new Intent(MyApp.getContext(), A.class);
    i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    MyApp.getContext().startActivity(i);
  }

http://stackoverflow.com/questions/15564614/how-to-restart-an-android-application-programmatically