Question

我想实现应用程序的一部分，该部分将采取一些由演示者处理的步骤。我已经声明了一个范围：

@Scope
annotation class FormScope

接下来，我想声明一个模块，该模块将提供必要的依赖项：

    @Module
object FormModule {

    @JvmStatic
    @Provides
    fun providesFragmentManager(activity: FragmentActivity): FragmentManager = activity.supportFragmentManager

    @JvmStatic
    @Provides
    fun providesNavigation(fragmentManager: FragmentManager): SobergridCoachingNavigationUnauthorizedFirstStep = SobergridCoachingNavigationUnauthorizedFirstStep(fragmentManager)

    @JvmStatic
    @Provides
    fun providesCoordinator(navigation: NavigationUnauthorized): CoordinatoUnauthorized = CoordinatoUnauthorized(navigation)

    @JvmStatic
    @Provides
    @Reusable
    fun providesPresenter(coordinator: CoordinatoUnauthorized): OnboardingFragmentContract.Presenter = FormPresenter(coordinator)

}

最后，我将模块绑定到片段中，然后将依赖项注入到这些片段中：

@Module(includes = [AndroidSupportInjectionModule::class])
abstract class FragmentBindingModule {

    @FormScope
    @ContributesAndroidInjector(modules = [FormFirstModule::class, FormModule::class])
    abstract fun contributesFormFirst(): FormFirstFragment
    @ContributesAndroidInjector(modules = [FormSecondModule::class, FormModule::class])
    abstract fun contributesFormSecond(): FormSecondFragment
    @ContributesAndroidInjector(modules = [FormThirdModule::class, FormModule::class])
    abstract fun contributesFormThird(): FormThirdFragment
}

我遇到的问题是，每次显示新片段时，Dagger都会创建一个Presenter的新实例。我想为所有这些片段使用一个演示者。我做错了什么？我应该改善什么才能实现自己的目标？

更新

我还尝试用@Singleton注释我的provide方法

    @JvmStatic
    @Provides
    @Signleton
    fun providesPresenter(coordinator: CoordinatoUnauthorized): OnboardingFragmentContract.Presenter = FormPresenter(coordinator)

但这会导致编译错误。我尝试的最后一件事是在Presenter类的声明之前放置注释（@Reusable和@Singleton）。这种方法不会给我带来任何编译错误，但是Presenter类的实例仍然不止一个。

Answer 1

将您的Presenter提供给具有Scope的FragmentActivity模块，以便为Activity中的所有片段获得相同的Presenter

@Module
public class FragmentActivityModule {

    //common provides for all fragments
    @Provides
    @FormScope
    public YourPresenter providesYourPresenter() {
        return new YourPresenter();
    }

    ....

您的建造者必须看起来像这样

@Module
public abstract class ActivityBuilder {

@FormScope
@ContributesAndroidInjector(modules = {FragmentActivityModule.class, Form1FragmentProvider.class
        , Form2FragmentProvider.class})
abstract FragmentActivity bindFragmentActivity();

在Form1FragmentModule中仅为Form1Fragment提供。为所有片段Form1FragmentProvider，Form2FragmentProvider ...创建FragmentProviders ...

@Module
public abstract class Form1FragmentProvider {

    @ContributesAndroidInjector(modules = Form1FragmentModule.class)

    abstract Form1Fragment provideForm1FragmentFactory();
}

不要忘记在FragmentActivity中实现HasSupportFragmentInjector

public class  FragmentActivity extends AppCompatActivity implements HasSupportFragmentInjector {

    @Inject
    DispatchingAndroidInjector<Fragment> fragmentDispatchingAndroidInjector;

....

@Override
    public AndroidInjector<Fragment> supportFragmentInjector() {
        return fragmentDispatchingAndroidInjector;
    }

别忘了在片段中附加AndroidSupportInjection

@Override
    public void onAttach(Context context) {
        AndroidSupportInjection.inject(this);
        super.onAttach(context);
    }

Dagger 2 + MVP-将一个演示者分配给多个片段

1 个答案: