Added in API level 18
    OnWindowFocusChangeListener
interface OnWindowFocusChangeListener
| android.view.ViewTreeObserver.OnWindowFocusChangeListener | 
Interface definition for a callback to be invoked when the view hierarchy's window focus state changes.
Summary
| Public methods | |
|---|---|
| abstract Unit | onWindowFocusChanged(hasFocus: Boolean)Callback method to be invoked when the window focus changes in the view tree. | 
Public methods
onWindowFocusChanged
Added in API level 18
      abstract fun onWindowFocusChanged(hasFocus: Boolean): Unit
Callback method to be invoked when the window focus changes in the view tree.
| Parameters | |
|---|---|
| hasFocus | Boolean: Set to true if the window is gaining focus, false if it is losing focus. | 
