Dagger2，同时提供不同API的Retrofit实例

Question

在我的项目中，我使用 Retrofit 并尝试使用 Dagger 来注入依赖项。我还有 2 个具有不同 API 的 Retrofit 服务。我需要同时使用 2 个具有不同 baseUrls 的不同 API。我卡在这里，不知道下一步该做什么。

我的应用模块：

@Module
public class ApplicationModule {

private String FIRST_API_URL = "https://first-api.com";
private String SECOND_API_URL = "https://second-api.com";

private String mBaseUrl;
private Context mContext;

public ApplicationModule(Context context) {
    mContext = context;
}

@Singleton
@Provides
GsonConverterFactory provideGsonConverterFactory() {
    return GsonConverterFactory.create();
}

@Singleton
@Provides
@Named("ok-1")
OkHttpClient provideOkHttpClient1() {
    return new OkHttpClient.Builder()
            .connectTimeout(20, TimeUnit.SECONDS)
            .readTimeout(20, TimeUnit.SECONDS)
            .build();
}

@Singleton
@Provides
@Named("ok-2")
OkHttpClient provideOkHttpClient2() {
    return new OkHttpClient.Builder()
            .connectTimeout(60, TimeUnit.SECONDS)
            .readTimeout(60, TimeUnit.SECONDS)
            .build();
}

@Singleton
@Provides
RxJavaCallAdapterFactory provideRxJavaCallAdapterFactory() {
    return RxJavaCallAdapterFactory.create();
}

@Singleton
@Provides
@FirstApi
Retrofit provideRetrofit(@Named("ok-1") OkHttpClient client, GsonConverterFactory converterFactory, RxJavaCallAdapterFactory adapterFactory) {
    return new Retrofit.Builder()
            .baseUrl(FIRST_API_URL)
            .addConverterFactory(converterFactory)
            .addCallAdapterFactory(adapterFactory)
            .client(client)
            .build();
}

@Singleton
@Provides
@SecondApi
Retrofit provideRetrofit2(@Named("ok-1") OkHttpClient client, GsonConverterFactory converterFactory, RxJavaCallAdapterFactory adapterFactory) {
    return new Retrofit.Builder()
            .baseUrl(SECOND_API_URL)
            .addConverterFactory(converterFactory)
            .addCallAdapterFactory(adapterFactory)
            .client(client)
            .build();
}

@Provides
@Singleton
Context provideContext() {
    return mContext;
}
}

我的申请：

public class MyApplication extends Application {

private ApplicationComponent mApplicationComponent;

@Override
public void onCreate() {
    super.onCreate();
    initializeApplicationComponent();
}

private void initializeApplicationComponent() {
    mApplicationComponent = DaggerApplicationComponent
            .builder()
            .applicationModule(new ApplicationModule(this, Constant.BASE_URL))   // I think here needs to do something to use different URLs
            .build();
}

public ApplicationComponent getApplicationComponent() {
    return mApplicationComponent;
}

@Override
public void onTerminate() {
    super.onTerminate();
}
}

这就是我在我的片段中解决依赖关系的方式。

    protected void resolveDependency() {
    DaggerSerialComponent.builder()
            .applicationComponent(getApplicationComponent())
            .contactModule(new ContactModule(this))
            .build().inject(this);
}

问题是我需要在Fragment中使用2个API进行注入，才能从这些API中获取数据。

更新： 我创建了注释：

@Qualifier
@Retention(RUNTIME)
public @interface FirstApi{}

@Qualifier
@Retention(RUNTIME)
public @interface SecondApi{}

我的联系人模块：

@Module
public class ContactModule {

private ContactView mContactView;

public ContactModule(ContactView contactView) {
    mContactView = contactView;

}

@PerActivity
@Provides
FirstContactService provideFirstContactService(@FirstApi Retrofit retrofit) {
    return retrofit.create(FirstContactService.class);
}

@PerActivity
@Provides
SecondContactService provideSecondContactService(@SecondApi Retrofit retrofit) {
    return retrofit.create(SecondContactService.class);
}

@PerActivity
@Provides
ContactView provideContactView() {
    return mContactView;
}
}

我总是报错"retrofit2.retrofit cannot be provided without and @Provides or @Produces-annotated method"

应用组件

@Singleton
@Component(modules = ApplicationModule.class)
public interface ApplicationComponent {

    Retrofit exposeRetrofit();

    Context exposeContext();
}

Answer 1

您只需将 @Inject 注释与 @Named() 注释一起使用，如下所示：

@Inject @Named("provideRetrofit") Retrofit mRetrofit;
@Inject @Named("provideRetrofit2") Retrofit mRetrofit2;

或者您甚至可以直接注入 Retrofit 服务：

@Provides @Singleton
public CustomService provideCustomService(@Named("provideRetrofit") Retrofit retrofit) {
    return retrofit.create(CustomService.class);
}

Answer 2

向您提供的改造实例添加 @Named 注释，如下所示：

@Named("retrofit_one")
Retrofit provideRetrofit(@Named("ok-1") OkHttpClient client, GsonConverterFactory converterFactory, RxJavaCallAdapterFactory adapterFactory) {
return new Retrofit.Builder()
.baseUrl(FIRST_API_URL) 
.addConverterFactory(converterFactory) 
.addCallAdapterFactory(adapterFactory) 
.client(client) 
.build();
 }



@Named("retrofit_two")
    Retrofit provideRetrofit(@Named("ok-1") OkHttpClient client, GsonConverterFactory converterFactory, RxJavaCallAdapterFactory adapterFactory) {
    return new Retrofit.Builder()
    .baseUrl(SECOND_API_URL) 
    .addConverterFactory(converterFactory) 
    .addCallAdapterFactory(adapterFactory) 
    .client(client) 
    .build();
     }

然后在任何需要的地方注入两个实例：

@Inject @Named("retrofit_one") Retrofit mRetrofitOne;   
@Inject @Named("retrofit_two") Retrofit mRetrofitTwo;

Dagger2，同时提供不同API的Retrofit实例

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