Android Glide + okhttp progress example

MainActivity.java

package com.example.glidetest.app;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ImageView;
import android.widget.ProgressBar;

import com.bumptech.glide.Glide;
import com.bumptech.glide.integration.okhttp.OkHttpUrlLoader;
import com.bumptech.glide.load.engine.DiskCacheStrategy;
import com.bumptech.glide.load.model.GlideUrl;
import com.squareup.okhttp.Interceptor;
import com.squareup.okhttp.MediaType;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Response;
import com.squareup.okhttp.ResponseBody;

import java.io.IOException;
import java.io.InputStream;

import okio.Buffer;
import okio.BufferedSource;
import okio.ForwardingSource;
import okio.Okio;
import okio.Source;

/*
   For more information see:
   https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/com/squareup/okhttp/recipes/Progress.java
*/

public class MainActivity extends AppCompatActivity {
    private static final String LOG_TAG = "MainActivity";

    private final static String DOWNLOAD_URL = "https://i.imgur.com/mYBXl6X.jpg";

    private OkHttpClient mOkHttpClient;

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

        final ImageView imageView = (ImageView) findViewById(R.id.image_view);

        final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);

        mOkHttpClient = new OkHttpClient();

        final ProgressListener progressListener = new ProgressListener() {
            @Override
            public void update(long bytesRead, long contentLength, boolean done) {
                int progress = (int) ((100 * bytesRead) / contentLength);

                // Enable if you want to see the progress with logcat
                // Log.v(LOG_TAG, "Progress: " + progress + "%");
                progressBar.setProgress(progress);
                if (done) {
                    Log.i(LOG_TAG, "Done loading");
                }
            }
        };

        mOkHttpClient.networkInterceptors().add(new Interceptor() {
            @Override
            public Response intercept(Chain chain) throws IOException {
                Response originalResponse = chain.proceed(chain.request());
                return originalResponse.newBuilder()
                        .body(new ProgressResponseBody(originalResponse.body(), progressListener))
                        .build();
            }
        });

        Glide.get(this)
                .register(GlideUrl.class, InputStream.class, new OkHttpUrlLoader.Factory(mOkHttpClient));
        Glide.with(this)
                .load(DOWNLOAD_URL)
                // Disabling cache to see download progress with every app load
                // You may want to enable caching again in production
                .diskCacheStrategy(DiskCacheStrategy.NONE)
                .into(imageView);
    }

    private static class ProgressResponseBody extends ResponseBody {

        private final ResponseBody responseBody;
        private final ProgressListener progressListener;
        private BufferedSource bufferedSource;

        public ProgressResponseBody(ResponseBody responseBody, ProgressListener progressListener) {
            this.responseBody = responseBody;
            this.progressListener = progressListener;
        }

        @Override
        public MediaType contentType() {
            return responseBody.contentType();
        }

        @Override
        public long contentLength() throws IOException {
            return responseBody.contentLength();
        }

        @Override
        public BufferedSource source() throws IOException {
            if (bufferedSource == null) {
                bufferedSource = Okio.buffer(source(responseBody.source()));
            }
            return bufferedSource;
        }

        private Source source(Source source) {
            return new ForwardingSource(source) {
                long totalBytesRead = 0L;

                @Override
                public long read(Buffer sink, long byteCount) throws IOException {
                    long bytesRead = super.read(sink, byteCount);
                    // read() returns the number of bytes read, or -1 if this source is exhausted.
                    totalBytesRead += bytesRead != -1 ? bytesRead : 0;
                    progressListener.update(totalBytesRead, responseBody.contentLength(), bytesRead == -1);
                    return bytesRead;
                }
            };
        }
    }

    interface ProgressListener {
        void update(long bytesRead, long contentLength, boolean done);
    }
}