OkHttp and Retrofit 2 caching and offline usage

Question

I want to store my server responses offline.

This is my code:

        public void loadJSON() {
        OkHttpClient client = new OkHttpClient.Builder()
                .connectTimeout(4, TimeUnit.SECONDS)
                .readTimeout(4, TimeUnit.SECONDS)
                .writeTimeout(4, TimeUnit.SECONDS)
                .build();
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(Config.URL_MAIN + sid + "/")
                .addConverterFactory(GsonConverterFactory.create())
                .client(client)
                .build();

        RequestInterfacePlanGesamt request = retrofit.create(RequestInterfacePlanGesamt.class);
        Call<JSONResponsePlanGesamt> call = request.getJSON();
        call.enqueue(new Callback<JSONResponsePlanGesamt>() {
            @Override
            public void onResponse(Call<JSONResponsePlanGesamt> call, Response<JSONResponsePlanGesamt> response) {
//bla bla
}
    }

    public interface RequestInterfacePlanGesamt {
        @Headers({
                "User-Agent: android"
        })
        @GET(Config.GESAMT)
        Call<JSONResponsePlanGesamt> getJSON();
    }

How can I use the content offline? I already read some articles about caching but I really don`t know how to achieve the offline usage of my content.

Answer 1

Just use the cache() method in your OkHttpClient Builder:

private static final long CACHE_SIZE = 10 * 1024 * 1024;    // 10 MB

OkHttpClient client = new OkHttpClient.Builder()
                .connectTimeout(4, TimeUnit.SECONDS)
                .readTimeout(4, TimeUnit.SECONDS)
                .writeTimeout(4, TimeUnit.SECONDS)
                .cache(new Cache(getApplication().getCacheDir(), CACHE_SIZE))
                .build();