Каким образом LifecycleOwner отслеживает и реагирует на изменение состояния компонента?

LifecycleOwner is an interface in Android that provides a Lifecycle object, which tracks the lifecycle state of a component (such as an Activity or Fragment).

It implements a mechanism to observe changes in the component's state using the Lifecycle class, which holds the current state (CREATED, STARTED, RESUMED, etc.) and notifies registered observers (LifecycleObservers) when this state changes.

When the component's lifecycle changes (for example, onStart(), onResume(), onPause(), etc. are called), the corresponding methods update the state in the Lifecycle object. This object then dispatches events to all subscribed observers, which can react to these changes, such as starting or stopping resources.

Example:

class MyActivity : AppCompatActivity(), LifecycleOwner {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        lifecycle.addObserver(MyObserver())
    }
}

class MyObserver : LifecycleObserver {
    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    fun onResume() {
        // Actions upon activity resumption
    }
}

Thus, LifecycleOwner provides a Lifecycle object that tracks the component's state and notifies observers of changes.