Note that the author is describing a custom View subclass, which is a couple of steps beyond "layout out your widgets". There used to be pretty comprehensive ex

Note that the author is describing a custom View subclass, which is a couple of steps beyond "layout out your widgets". There used to be pretty comprehensive examples on the developer site for how to do View invalidation properly (calling requestLayout willy-nilly isn't always it). Nowadays, they learned from many years and generations of GUI frameworks and... made a new GUI framework, Jetpack Compose UI.