目前，我正在使用这个：

class AutoClearedValue<T : Any>(val fragment: Fragment) : ReadWriteProperty<Fragment, T> {
    private var _value: T? = null

    init {
        fragment.lifecycle.addObserver(object: DefaultLifecycleObserver {
            override fun onCreate(owner: LifecycleOwner) {
                fragment.viewLifecycleOwnerLiveData.observe(fragment) { viewLifecycleOwner ->
                    viewLifecycleOwner?.lifecycle?.addObserver(object: DefaultLifecycleObserver {
                        override fun onDestroy(owner: LifecycleOwner) {
                            _value = null
                        }
                    })
                }
            }
        })
    }

    override fun getValue(thisRef: Fragment, property: KProperty<*>): T {
        return _value ?: throw IllegalStateException(
            "should never call auto-cleared-value get when it might not be available"
        )
    }

    override fun setValue(thisRef: Fragment, property: KProperty<*>, value: T) {
        _value = value
    }
}

/**
 * Creates an [AutoClearedValue] associated with this fragment.
 */
fun <T : Any> Fragment.autoCleared() = AutoClearedValue<T>(this)

但在我看来，既然我们需要在DestroyView（）中使用_binding = null
初始化部分应为：

override fun onDestroyView(owner: LifecycleOwner) {
    super.onDestroyView(owner)
    _value = null
}

但在我的课堂上，它只是做：

override fun onDestroy(owner: LifecycleOwner) {
    _value = null
}

但是onDestroyView在DefaultLifecycleObserver中不存在。我如何才能做到这一点？