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android - Unable to Inject ViewModel from a different module in Android project

问题描述

I am not sure if this is a limitation of the Dagger Hilt library, but i seem to be unable to inject a ViewModel from a different module in activity.

Project:
  :modA (OrderViewModel with @HiltViewModel annotation)
  :modUI (DI stuff here that injects OrderViewModel in Activity) with dependency on modA
  :modOther

@HiltViewModel
class OrderViewModel @Inject constructor(
    private val loadOrdersUseCase: LoadOrdersUseCase,
    private val updateOrderUseCase: UpdateOrderUseCase,
    private val mapper: OrderDataMapper,
) : SharedViewModel<OrderDataModel>()

which is injected like:


private val orderViewModel: OrderViewModel by viewModels()

I can't see the respective OrderViewModel_HiltModules and OrderViewModel_HiltModules classes generated. In fact, when I ran the app it crashes with crash below, which indicates, their ViewModel is not in the ViewModel keymap that hilt should have created.

Caused by: java.lang.RuntimeException: Cannot create an instance of class com.rowland.delivery.presentation.viewmodels.order.OrderViewModel
.
.
.
Caused by: java.lang.InstantiationException: java.lang.Class<com.rowland.delivery.presentation.viewmodels.order.OrderViewModel> has no zero argument constructor
        at java.lang.Class.newInstance(Native Method)
        at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.java:219)

Is this a limitation of Dagger Hilt? Any insights would be appreciated.

For anyone who has the time to reproduce it, you can take a look at the following branch of the code:

标签： androiddagger-2android-viewmodeldagger-hilt

解决方案

看起来编译器是解决这个多模块问题的关键。使用任何 Dagger Hilts 属性注释的任何模块也需要定义 dagger hilt 依赖项和编译器，即：

    implementation 'com.google.dagger:hilt-android:2.31.2-alpha'
    kapt 'com.google.dagger:hilt-android-compiler:2.31.2-alpha'
    implementation "androidx.hilt:hilt-lifecycle-viewmodel:1.0.0-alpha03"
    kapt 'androidx.hilt:hilt-compiler:1.0.0-alpha03'

否则，将不会生成相应的绑定/提供程序。在这种情况下，根本没有生成 ViewModel 提供程序。

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