Kotlin 实现的Lifecycle 生命周期管理，用于其他对象观察当前activity、fragment的生命周期状态变化 代码借鉴android 官方 Lifecycle 的源码实现
class LifeMainActivity : LifecycleAppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_life_main)
// 添加观察者
lifecycleRegistry.addObserver(TestLife())
}
}
class TestLife : LifecycleObserver {
override fun onStateChanged(lifecycleOwner: LifecycleOwner, event: Lifecycle.Event) {
Log.d("TestLife", event.name)
}
}
