You need to create a specific OkHttp client which will intercept the network requests and send updates. This client should only be used for downloads.
First you are going to need an interface, like this one:
public interface OnAttachmentDownloadListener {
void onAttachmentDownloadedSuccess();
void onAttachmentDownloadedError();
void onAttachmentDownloadedFinished();
void onAttachmentDownloadUpdate(int percent);
}
Your download call should return a ResponseBody, which we will extend from to be able to get the download progress.
private static class ProgressResponseBody extends ResponseBody {
private final ResponseBody responseBody;
private final OnAttachmentDownloadListener progressListener;
private BufferedSource bufferedSource;
public ProgressResponseBody(ResponseBody responseBody, OnAttachmentDownloadListener progressListener) {
this.responseBody = responseBody;
this.progressListener = progressListener;
}
@Override public MediaType contentType() {
return responseBody.contentType();
}
@Override public long contentLength() {
return responseBody.contentLength();
}
@Override public BufferedSource source() {
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);
totalBytesRead += bytesRead != -1 ? bytesRead : 0;
float percent = bytesRead == -1 ? 100f : (((float)totalBytesRead / (float) responseBody.contentLength()) * 100);
if(progressListener != null)
progressListener.onAttachmentDownloadUpdate((int)percent);
return bytesRead;
}
};
}
}
Then you will need to create your OkHttpClient like this
public OkHttpClient.Builder getOkHttpDownloadClientBuilder(OnAttachmentDownloadListener progressListener) {
OkHttpClient.Builder httpClientBuilder = new OkHttpClient.Builder();
// You might want to increase the timeout
httpClientBuilder.connectTimeout(20, TimeUnit.SECONDS);
httpClientBuilder.writeTimeout(0, TimeUnit.SECONDS);
httpClientBuilder.readTimeout(5, TimeUnit.MINUTES);
httpClientBuilder.addInterceptor(new Interceptor() {
@Override
public Response intercept(Chain chain) throws IOException {
if(progressListener == null) return chain.proceed(chain.request());
Response originalResponse = chain.proceed(chain.request());
return originalResponse.newBuilder()
.body(new ProgressResponseBody(originalResponse.body(), progressListener))
.build();
}
});
return httpClientBuilder;
}
Finally you only have to create your Retrofit client a different way, by passing your new OkHttp client. Based on your code, you can use something like this:
public Retrofit getDownloadRetrofit(OnAttachmentDownloadListener listener) {
return new Retrofit.Builder()
.baseUrl("http://192.168.43.135/retro/")
.addConverterFactory(GsonConverterFactory.create())
.client(getOkHttpDownloadClientBuilder(listener).build())
.build();
}
Your listener will handle the creation of your notification or whatever else you want.
