How to use setCache for online data OkHttpClient in Android

Question

I want to show 3 fragments in my Activity and load data from json in any fragments! I need to show website data into Recyclerview with OkHTTP v3 library.
I want to show this data for offline, I mean, if user turn off data/wifi show this datas for offline. but i do not want use SQLite Database!
For this idea i use okHttpClient cache , but not found setCache for client and show me this Error : Image link

MainActivity codes:

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private ArrayList<AndroidVersion> data;
    private DataAdapter adapter;
    private static Context context;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        context = this;

        initViews();
    }

    private void initViews() {
        recyclerView = (RecyclerView) findViewById(R.id.card_recycler_view);
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(layoutManager);
        loadJSON();
    }

    private void loadJSON() {

        OkHttpClient client = new OkHttpClient();
        client.networkInterceptors().add(REWRITE_CACHE_CONTROL_INTERCEPTOR);

        //setup cache
        File httpCacheDirectory = new File(context.getCacheDir(), "responses");
        int cacheSize = 10 * 1024 * 1024; // 10 MiB
        Cache cache = new Cache(httpCacheDirectory, cacheSize);

        //add cache to the client
        client.setCache(cache);

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://api.learn2crack.com")
                .client(client)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
        RequestInterface request = retrofit.create(RequestInterface.class);
        Call<JSONResponse> call = request.getJSON();
        call.enqueue(new Callback<JSONResponse>() {
            @Override
            public void onResponse(Call<JSONResponse> call, Response<JSONResponse> response) {

                JSONResponse jsonResponse = response.body();
                data = new ArrayList<>(Arrays.asList(jsonResponse.getAndroid()));
                adapter = new DataAdapter(data);
                recyclerView.setAdapter(adapter);
            }

            @Override
            public void onFailure(Call<JSONResponse> call, Throwable t) {
                Log.d("Error", t.getMessage());
            }
        });
    }

    private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {
        @Override
        public okhttp3.Response intercept(Chain chain) throws IOException {
            okhttp3.Response originalResponse = chain.proceed(chain.request());
            if (isNetworkAvailable(context)) {
                int maxAge = 60; // read from cache for 1 minute
                return originalResponse.newBuilder()
                        .header("Cache-Control", "public, max-age=" + maxAge)
                        .build();
            } else {
                int maxStale = 60 * 60 * 24 * 28; // tolerate 4-weeks stale
                return originalResponse.newBuilder()
                        .header("Cache-Control", "public, only-if-cached, max-stale=" + maxStale)
                        .build();
            }
        }
    };

    public static boolean isNetworkAvailable(Context context) {
        ConnectivityManager cm =
                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        return activeNetwork != null &&
                activeNetwork.isConnectedOrConnecting();
    }

}

How can i fix this and use okHttpClient cache?

Answer 1

From the screenshot, it is apparent you are using an outdated version of OkHttp. Retrofit 2 requires OkHttp 3. (The latest right now is 3.4.1.)

Also, to set the cache on the client in OkHttp 3, new OkHttpClient.Builder().cache(cache).build().