Reliable focus on a view on Android

StubbornFocus.kt

// Sample using RxJava 1.x, Kotlin
var offSwitch = false
Observable
        .interval(0, 100L, TimeUnit.MILLISECONDS)
        .observeOn(AndroidSchedulers.mainThread())
        .takeIf { !offSwitch }
        .subscribe {
            // try to focus every 100 milliseconds until the view or any of its children is focused
            view.accessibilityFullFocus()
            offSwitch = view.isAccessibilityFocused || view.hasAccessibilityFocusedChild
        }