ViewModelFactory
,将提供我们从ViewModelModule
public class ViewModelFactory implements ViewModelProvider.Factory {
private final Map<Class<? extends ViewModel>, Provider<ViewModel>> viewModels;
@Inject
public ViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> viewModels) {
this.viewModels = viewModels;
}
@Override
public <T extends ViewModel> T create(Class<T> modelClass) {
Provider<ViewModel> viewModelProvider = viewModels.get(modelClass);
if (viewModelProvider == null) {
throw new IllegalArgumentException("model class " + modelClass + " not found");
}
return (T) viewModelProvider.get();
}
}
ViewModelModule
负责结合各地视图模型类为
Map<Class<? extends ViewModel>, Provider<ViewModel>> viewModels
@Module
public abstract class ViewModelModule {
@Binds
@IntoMap
@ViewModelKey(UserViewModel.class)
abstract ViewModel userViewModel(UserViewModel userViewModel);
//Others ViewModels
}
ViewModelKey
右视图模型是一个注释作为地图中的钥匙使用,看起来像
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@MapKey
@interface ViewModelKey {
Class<? extends ViewModel> value();
}
现在你可以从图中创建视图模型,并满足所有必要的相关解决此
public class UserViewModel extends ViewModel {
private UserFacade userFacade;
@Inject
public UserViewModel(UserFacade userFacade) { // UserFacade should be defined in one of dagger modules
this.userFacade = userFacade;
}
}
实例化视图模型
public class MainActivity extends AppCompatActivity {
@Inject
ViewModelFactory viewModelFactory;
UserViewModel userViewModel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
((App) getApplication()).getAppComponent().inject(this);
userViewModel = ViewModelProviders.of(this, viewModelFactory).get(UserViewModel.class);
}
}
讨论:https://www.reddit.com/ R/androiddev /评论/ 6bw1jj/architecture_components_introduction_google_io_17 / –