Fragment.viewLifecycleOwnerLiveData.observe 不调用 kodein

Question

我正在制作一个应用程序，我想将我的UI逻辑分离到多个UI类中，其中BaseUi类具有生命周期意识。我使用Kodein作为我的DI，我有一个问题，fragment.viewLifecycleOwnerLiveData.observe不被调用时，我的ui类的实例是由Kodein检索。这是我的Fragment类:

class ListFragment : Fragment(), DIAware {
override val di: DI by closestDI()
override val diTrigger: DITrigger = DITrigger()
private var binding: FragmentMoviesBinding? = null
private val fragmentBinding get() = binding
private val kodeinMoviesUi: MoviesUi by instance() //fragment does not observe viewLifecycleOwnerLiveData
private val moviesUi: MoviesUi = MoviesUi(this) //fragment now observe viewLifecycleOwnerLiveData
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
binding = FragmentMoviesBinding.inflate(inflater, container, false)
return binding?.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
diTrigger.trigger()
}
override fun onDestroyView() {
super.onDestroyView()
binding = null
}
}

BaseUi类:

abstract class BaseUi<F : Fragment>(private val fragment: F) : LifecycleObserver {
init {
fragment.viewLifecycleOwnerLiveData.observe(fragment, { subscribeToLifecycle() })
}
private fun subscribeToLifecycle() {
fragment.viewLifecycleOwner.lifecycle.addObserver(object : LifecycleObserver {
@OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
fun onCreate() {
onViewCreated()
}
})
}
abstract fun onViewCreated()
}

和UiModule:

val uiModule = DI.Module("uiModule") {
bind<ListFragment>() with provider { ListFragment() }
bind<MoviesUi>() with provider { MoviesUi(instance()) }
}

Answer 1

来自https://github.com/Kodein-Framework/Kodein-DI/issues/353

这是你的问题，bind<ListFragment>() with provider { ListFragment() }。

您将ListFragment与提供程序绑定，这意味着每次您请求容器时，它都会创建ListFragment的实例。所以，当你用private val kodeinMoviesUi: MoviesUi by instance()注入MoviesUi时，它会得到ListFragment的另一个实例。

我建议你将MoviesUi的绑定定义为一个工厂，等待接收ListFragment的实例:bind<MoviesUi>() with factory {fragment: ListFragment -> MoviesUi(fragment) }然后你可以将它注入ListFragment中，如下所示:private val kodeinMoviesUi: MoviesUi by instance(args = this)