lifecycleState property
Whether the application is visible, and if so, whether it is currently interactive.
This is set by handleAppLifecycleStateChanged when the SystemChannels.lifecycle notification is dispatched.
The preferred way to watch for changes to this value is using WidgetsBindingObserver.didChangeAppLifecycleState.
Implementation
AppLifecycleState get lifecycleState => _lifecycleState;