java - 使用 Retrofit 和 dagger 2 动态更改基本 Url

Question

我正在为我的应用程序使用 Retrofit & Dagger2。我想根据用户在 Spinner 中选择的内容动态更改应用程序的 baseUrl。

在互联网上花了几个小时后，我得出的结论是可以动态更改 baseUrl。

依赖注入(inject)如下所示:

APi模块

  @Module
public class ApiModule {

 String mBaseUrl;

    public ApiModule(String mBaseUrl) {
        this.mBaseUrl = mBaseUrl;
    }

@Provides
    @Singleton
    OkHttpClient provideOkhttpClient(Cache cache) {
        OkHttpClient.Builder client = new OkHttpClient.Builder();           
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        // set your desired log level
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);
        client.addInterceptor(logging);
        client.cache(cache);
        return client.build();   
    }

    @Provides
    @Singleton
    Retrofit provideRetrofit(OkHttpClient okHttpClient) {
        return new Retrofit.Builder()
                .addConverterFactory(GsonConverterFactory.create())
                .baseUrl(mBaseUrl)
                .client(okHttpClient)
                .build();
    }
}

我根据互联网上的引用创建了一个额外的类(class)

HostSelectionInterceptor.java

import java.io.IOException;
import javax.inject.Singleton;
import dagger.Module;
import dagger.Provides;
import okhttp3.HttpUrl;
import okhttp3.Interceptor;
import okhttp3.Request;
/** An interceptor that allows runtime changes to the URL hostname. */
@Module(includes = {ApiModule.class})
public final class HostSelectionInterceptor implements Interceptor {
    private volatile String host;

    @Provides
    @Singleton
    public String setHost(String host) {
        this.host = host;
        return this.host;
    }

    public String getHost() {
        return host;
    }

    @Provides
    @Singleton
    @Override
    public okhttp3.Response intercept(Chain chain) {
        Request request = chain.request();
        String  host    = getHost();
        if (host != null) {
           /* HttpUrl newUrl = request.url().newBuilder()
                    .host(host)
                    .build();*/
            HttpUrl newUrl = HttpUrl.parse(host);
            request = request.newBuilder()
                    .url(newUrl)
                    .build();
        }
        try {
            return chain.proceed(request);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }
}

现在，我的问题是如何使用 HostSelectionInterceptor 来更改 Spinner 时的 baseUrl。

Answer 1

您可以使用@Named(或使用@Qualifier注释的自定义注释)添加如下注释:

@Singleton
@Provides
@Named("picture")
Retrofit providePictureRetrofit(GsonConverterFactory gsonConverterFactory, RxJavaCallAdapterFactory rxJavaCallAdapterFactory) {
    return retrofit = new Retrofit.Builder()
            .baseUrl(MarsWeatherWidget.PICTURE_URL) // one url
            .build();
}



@Singleton
@Provides
@Named("weather")
Retrofit provideWeatherRetrofit(GsonConverterFactory gsonConverterFactory, RxJavaCallAdapterFactory rxJavaCallAdapterFactory) {
    return retrofit = new Retrofit.Builder()
            .baseUrl(MarsWeatherWidget.WEATHER_URL) // other url
            .build();
}

注入(inject)合格版本

当您的模块提供限定类型时，您只需要在需要依赖项的位置添加限定符即可。

MyPictureService provideService(@Named("picture") Retrofit retrofit) {
    // ...
}