Question

我刚刚回到Java和Android世界。在我寻找一个利用编译时间DI和MvvM的好项目启动器时，我找到了这两个：

Writing Testable Android MVVM
Countries - A sample Android app

现在我的问题...... 我想让基本活动看起来像这样（保留重要部分）：

public abstract class ViewModelActivity<VM extends IViewModel> extends AppCompatActivity {

private ActivityComponent activityComponent;
@Inject
private VM viewModel;

protected void inject(AppComponent appComponent) {
    appComponent.inject(this);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    AppComponent appComponent = ((MvvmApplication) getApplication()).getAppComponent();
    inject(appComponent);

    activityComponent =
            DaggerActivityComponent.builder()
            .appComponent(appComponent)
            .activityModule(new ActivityModule(this))
            .build();

    ViewModel.State savedViewModelState = null;
    if (savedInstanceState != null) {
        savedViewModelState = savedInstanceState.getParcelable(EXTRA_VIEW_MODEL_STATE);
    }
    viewModel = createViewModel(savedViewModelState);
}

}

所以我的AppComponent应该是这样的：

@AppScope
@Component(modules = {
    AppContextModule.class,
    AppModule.class,
    NetworkModule.class,
    GsonModule.class
})
public interface MyAppComponent extends AppComponent {

    void inject(DashboardActivity baseActivity);

    Picasso picasso();

}

AppComponent的位置：

@AppScope
public interface AppComponent {

    Context appContext();

    void inject(ViewModelActivity viewModelActivity);

}

最后具体的活动是：

public class DashboardActivity extends ViewModelActivity<DashboardViewModel> {}

现在我不断收到以下错误：

Error:(29, 10) error: activities.dashboard.DashboardViewModel cannot be 
provided without an @Inject constructor or from an @Provides- or @Produces-
annotated method. This type supports members injection but cannot be 
implicitly provided.
activities.dashboard.DashboardViewModel is injected at
mvvm.activity.ViewModelActivity.viewModel
activities.dashboard.DashboardActivity is injected at
app.inject(baseActivity)

我错过了什么？

谢谢！

Answer 1

要使用带有匕首的MVVM，请查看来自Google的this sample code

它确实做得很好，它也使用了匕首的最新趋势，比如定义子模块和使用新的AndroidInjection注入活动和片段。它还使用自定义工厂来创建视图模型，该模型负责注入构造函数字段。

Android Clean MVVM With Dagger 2

1 个答案: