Добрый день столкнулся тоже с этой проблемой но ваш метод не подходит.
CallInUIThread(
procedure
var
DM: JDisplayMetrics;
VideoView: JVideoView;
//Container: JRelativeLayout;
//param: JRelativeLayout_LayoutParams;
NativeLayout: JNativeLayout;
begin
DM := GetJDisplayMetrics;
VideoView := TJVideoView.JavaClass.init(SharedActivity);
VideoView.setMinimumWidth(DM.widthPixels);
VideoView.setMinimumHeight(DM.heightPixels);
VideoView.setVideoPath(StringToJString('http://clips.vorwaerts-gmbh.de/VfE_html5.mp4'));
VideoView.requestFocus();
VideoView.start();
RelativeLayout := JRelativeLayout.JavaClass.init(SharedActivity, MainActivity.getTextEditorProxy.getWindowToken);
NativeLayout.SetPosition(10, 10);
NativeLayout.SetSize(300, 300);
NativeLayout.SetControl(VideoView);
NativeLayout.SetFocus(true);
end);