Question

我正在尝试注入活动的视图模型，并且想在Dialog Fragment中使用它，如何用Kodein注入它？并使用我之前在其他活动或片段中注入的视图模型。

我已经尝试过中等水平的教程，这是教程

https://proandroiddev.com/android-viewmodel-dependency-injection-with-kodein-249f80f083c9

我正在尝试从活动的视图模型访问注入结果但是当我尝试从Dialog Fragment访问viewModel内部的某些对象时，该值为null与活动的viewModel不相同

// This is from Activity
private val viewModelFactory: TriplogisticViewModelFactory by instance()
    private val viewModel: TriplogisticViewModel by lazy {
        ViewModelProviders
            .of(this@ContactDetailBottomSheetDialogFragment, viewModelFactory)
            .get(TriplogisticViewModel::class.java)
}

Log.e("VIEWMODEL_ACTIVITY", viewModel.mode.get().toString) // result is SENDER_MODE

我期望当我访问对话框片段的viewModel中的某个对象时，我得到的值与活动的viewModel相同

// This is from Dialog Fragment
private val viewModelFactory: TriplogisticViewModelFactory by instance()
    private val viewModel: TriplogisticViewModel by lazy {
        ViewModelProviders
            .of(this@ContactDetailBottomSheetDialogFragment, viewModelFactory)
            .get(TriplogisticViewModel::class.java)
}

我想要与活动的viewModel对象相同的结果，但结果为空

Log.e("VIEWMODEL_FRAGMENT", viewModel.mode.get().toString) // result is null

Answer 1

您必须使用共享的ViewModel。使用活动所有者实例化ViewModel。看起来像：

class SharedViewModel : ViewModel() {
    val selected = MutableLiveData<Item>()

    fun select(item: Item) {
        selected.value = item
    }
}

class MasterFragment : Fragment() {

    private lateinit var itemSelector: Selector

    private lateinit var model: SharedViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        model = activity?.run {
            ViewModelProviders.of(this)[SharedViewModel::class.java]
        } ?: throw Exception("Invalid Activity")
        itemSelector.setOnClickListener { item ->
            // Update the UI
        }
    }
}

class DetailFragment : Fragment() {

    private lateinit var model: SharedViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        model = activity?.run {
            ViewModelProviders.of(this)[SharedViewModel::class.java]
        } ?: throw Exception("Invalid Activity")
        model.selected.observe(this, Observer<Item> { item ->
            // Update the UI
        })
    }
}

有关详细信息，请单击here

我可以在对话框片段中注入活动的视图模型并使用它吗

1 个答案: