如何在Dagger2中提供视图？

Question

Below is the Activity, it is still using an old DI model, and i'm trying to migrate to Dagger2 (with dagger-android). I want to inject the Presenter, and as you can see, one dependency is the 'NewProjectDisplayer' which is a custom view in the activity.

This is the 'NewProjectDisplayer' which I want to provide to the Presenter

I have a Module (AppModule) which provides the global dependencies like ProjectService, LoginService etc..

Below is the NewProjectModule which I am having trouble with. One of the dependencies which is tied to the activity is the 'NewProjectDisplayer'. And I have no idea how I can provide it..

@Module
public class NewProjectActivityModule {

    @Provides
    NewProjectDisplayer provideNewProjectDisplayer(View view) {
        // ??? return view.findViewById(R.id.create_project_view);
    }

    @Provides
    NewProjectNavigator provideNewProjectNavigator(BaseActivity baseActivity) {
        return new AndroidNewProjectNavigator(baseActivity);
    }

    @Provides
    NewProjectPresenter provideNewProjectPresenter(NewProjectDisplayer displayer, //
                                                   ProjectService projectService,
                                                   LoginService loginService,
                                                   UserService userService,
                                                   NewProjectNavigator navigator, //
                                                   PermissionHandler permissionHandler,//
                                                   CropImageHandler cropImageHandler,//
                                                   RxSchedulers schedulers) {
        return new NewProjectPresenter(displayer, projectService, loginService,
                userService, navigator, permissionHandler, cropImageHandler, schedulers);
    }

}

How can I provide this 'NewProjectDisplayer' so that the Presenter can be created and injected? I am using dagger-android.

Answer 1

You can't provide or do a findViewById on an activity module that is compatible with dagger-android , one reason being that the module is created before the view is actually on the hierarchy. Also, doing this is a not a good practice, but if you're still convinced you should do this, you could try creating a sub component that will have a module that provides the view dependency and it has to be created after setContentView , as suggested by @elmorabea.

Answer 2

Just solving your problem, not sure if you should provide views with Dagger though.

Change your module to be something like that.

@Module
public class NewProjectActivityModule {

private View view;

public NewProjectActivityModule (View view) {
    this.view = view;
}

@Provides
NewProjectDisplayer provideNewProjectDisplayer(View view) {
    return view;
}

}

However, where ever you are creating your Dagger component you need to do something like that.

YourDaggerComponent.builder().newProjectActivityModule(new NewProjectActivityModule (yourViewInstance)).build();

Otherwise it will crash at run-time.