Question

I have a custom FrameLayout class which does some custom drawing on the OnSizeChanged event. It’s done there and not in the OnDraw event to avoid reentrancy and therefore performance issues. This works fine in a single activity application but fails in a TabActivity. The activity in the current tab renders fine but activities in non-active tabs are not being rendered. Here you can download an example project reproducing this. The project is HelloTabWidget but uses HelloAndroid project as well.

Found that onWindowVisibilityChanged event might help but need to find adequate size to plot my control. In the code snippet below I’d need a way to find container’s size at onWindowVisibilityChanged.

@Override
protected void onWindowVisibilityChanged(int visibility) {
    super.onWindowVisibilityChanged(visibility);

    int width = this.getWidth();
    int height = this.getHeight();

    drawContent(getCtxt(), width, height);
}

Answer 1

The solution was using OnDraw event doing some refactoring to the component and using a boolean flag to determine when the canvas is dirty to avoid unneeded reentrancy. SetWillNotDraw had to be set to false as well.