Use retrofit to download image file

Question

I use Retrofit 1.6.0 on my Android project,

the request url:

https://example.com/image/thumbs/filename/sample.png

My interface like this:

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Answer 1

I am playing with rxjava and retrofit these days, I have a quick demo here. Talk is cheap, show you my code directly, hope it helps.

public interface ImageService {

    String ENDPOINT = "HTTP://REPLACE.ME";

    @GET
    @Streaming
    Observable getThumbs(@Url String filepath);

    /********
     * Helper class that sets up a new services
     *******/
    class Instance {

        static ImageService instance;

        public static ImageService get() {
            if (instance == null)
                instance = newImageService();
            return instance;
        }

        public static ImageService newImageService() {
            Retrofit retrofit = new Retrofit.Builder()
                    .baseUrl(ImageService.ENDPOINT)
                    .addConverterFactory(BitmapConverterFactory.create())
                    .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                    .build();
            return retrofit.create(ImageService.class);
        }
    }
}

And I wrote my own BitmapConverterFactory to convert byte stream to bitmap:

public final class BitmapConverterFactory extends Converter.Factory {

    public static BitmapConverterFactory create() {
        return new BitmapConverterFactory();
    }


    private BitmapConverterFactory() {
    }

    @Override
    public Converter responseBodyConverter(Type type, Annotation[] annotations,
                                                                 Retrofit retrofit) {
        if (type == Bitmap.class) {
            return new Converter(){

                @Override
                public Bitmap convert(ResponseBody value) throws IOException {
                    return BitmapFactory.decodeStream(value.byteStream());
                }
            };
        } else {
            return null;
        }
    }

    @Override
    public Converter requestBodyConverter(Type type, Annotation[] annotations,
                                                          Retrofit retrofit) {
        return null;
    }
}

Gradle dependencies here:

final RETROFIT_VERSION = '2.0.0-beta3'
compile "com.squareup.retrofit2:retrofit:$RETROFIT_VERSION"
compile "com.squareup.retrofit2:adapter-rxjava:$RETROFIT_VERSION"

Cheers, vanvency