This time I found a workaround for it, and works fine. but just for the ndk demos.
on your ActivityGroup sub class onCreate method, write the following code.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LocalActivityManager lam = getLocalActivityManager();
Intent intent = new Intent();
intent.setClass(this, TeapotNativeActivity.class);
Window window = lam.startActivity("xxx", intent);
// reflect call "willYouTakeTheSurface"
NativeActivity callback = JavaCalls.callMethod(window.getDecorView(), "willYouTakeTheSurface");
if (callback != null) {
window.takeSurface(null);
getWindow().takeSurface(callback);
getWindow().takeInputQueue(callback);
}
setContentView(window.getDecorView());
}