android - 我是否需要手动清除ViewModel中的监听器变量以避免内存泄漏？

Question

如果我像这样设置了片段和视图模型，并从片段中设置了一个动作变量，因此有隐式引用，那么视图模型在死亡时会清除该引用本身，并打破潜在的引用周期，还是应该清除在viewModel.onCleared()中手动进行此操作？

class MyFragment: BaseFragment() {

    lateinit var viewModel: MyViewModel

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

        return FragmentMyBinding.inflate(inflater, container, false).also { binding ->

            binding.viewModel = ViewModelProviders.of(this).get(MyViewModel::class.java).apply {
                viewModel = this

                showLoader = {
                    // code to display loading spinner
                }
            }

            binding.lifecycleOwner = viewLifecycleOwner
        }.root
    }

}
...

class MyViewModel: ViewModel() {

    lateinit var showLoader: () -> Unit
...

Answer 1

您不应在ViewModel中执行任何与UI相关的操作。您的ViewModel应该通过Fragment/Activity将数据提供给您的Observer。我假设您想在加载数据之前显示一些指示器，然后再隐藏它。因此，在加载数据之前立即显示指标，然后将其隐藏在onChange的Observer中：

class MyFragment: BaseFragment() {

    lateinit var viewModel: MyViewModel

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        // show your indicator here
        showYourIndicator() 

        return FragmentMyBinding.inflate(inflater, container, false).also { binding ->

            binding.viewModel = ViewModelProviders.of(this).get(MyViewModel::class.java)
            binding.viewModel.loadSomeData().observe(this@MyFragment, {
                ...
                hideIndicator()
            }
            binding.lifecycleOwner = viewLifecycleOwner
        }.root
    }
}