Downloading two images at the same time with Picasso and using Target. But doesn't finish and load image

Question

So I'm downloading two images using Picasso at the same time, as follows:

 Picasso.with(this).load(Constants.SERVER_HOME_PAGE_TOP_IMAGE_URL).into(new Target() {
        @Override
        public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
            sLastBitmapLoadedDate = Calendar.getInstance();

            int h= (int) (Constants.PAGE_TOP_IMAGE_HEIGHT * densityMultiplier);
            int w= (int) (h * bitmap.getWidth()/((double) bitmap.getHeight()));
            sTipBitmap = Bitmap.createScaledBitmap(bitmap, w, h, true);

            Log.v("Image: ", "one");

            topImage.setImageBitmap(sTipBitmap);
        }

        @Override
        public void onBitmapFailed(Drawable errorDrawable) {
        }

        @Override
        public void onPrepareLoad(Drawable placeHolderDrawable) {
        }
    });

    Picasso.with(this).load(Constants.SERVER_HOME_PAGE_BOTTOM_IMAGE_URL).into(new Target() {
        @Override
        public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
            sLastBitmapLoadedDate = Calendar.getInstance();

            int h= (int) (Constants.PAGE_BOTTOM_IMAGE_HEIGHT * densityMultiplier);
            int w= (int) (h * bitmap.getWidth()/((double) bitmap.getHeight()));
            sAdBitmap = Bitmap.createScaledBitmap(bitmap, w, h, true);

            Log.v("Image: ", "two");

            bottomImage.setImageBitmap(sAdBitmap);
        }

        @Override
        public void onBitmapFailed(Drawable errorDrawable) {
        }

        @Override
        public void onPrepareLoad(Drawable placeHolderDrawable) {
        }
    });

I'm modifying the image size by using Target. So I never hit the onBitMapLoaded on both cases. If i comment out one of the requests, then it will load the image and hit the onBitMapLoaded, where i resize the image.

So I'm for sure going about this the wrong way. If someone could help me out and explain what I am doing wrong.

Thanks!

Answer 1

I've been there. Tried over 3 days to download multiple images using Picasso. However I found that the best way to download multiple images is to use a file downloader library. The FileDownloader library is an incredible choice as it allows to download multiple images in a queue both synchronously and asynchronously.

As a snapshot, this is how you'd download multiple images as a queue using this library:

    final FileDownloadListener queueTarget = new FileDownloadListener() {
            @Override
            protected void pending(BaseDownloadTask task, int soFarBytes, int totalBytes) {
            }

            @Override
            protected void connected(BaseDownloadTask task, String etag, boolean isContinue, int soFarBytes, int totalBytes) {
            }

            @Override
            protected void progress(BaseDownloadTask task, int soFarBytes, int totalBytes) {
            }

            @Override
            protected void blockComplete(BaseDownloadTask task) {
            }

            @Override
            protected void retry(final BaseDownloadTask task, final Throwable ex, final int retryingTimes, final int soFarBytes) {
            }

            @Override
            protected void completed(BaseDownloadTask task) {
            }

            @Override
            protected void paused(BaseDownloadTask task, int soFarBytes, int totalBytes) {
            }

            @Override
            protected void error(BaseDownloadTask task, Throwable e) {
            }

            @Override
            protected void warn(BaseDownloadTask task) {
            }
        };


final FileDownloadQueueSet queueSet = new FileDownloadQueueSet(downloadListener);

final List<BaseDownloadTask> tasks = new ArrayList<>();
for (int i = 0; i < count; i++) {
     tasks.add(FileDownloader.getImpl().create(Constant.URLS[i]).setTag(i + 1));
}

queueSet.disableCallbackProgressTimes(); // Do not need for each task callback `FileDownloadListener#progress`,
// We just consider which task will complete. so in this way reduce ipc will be effective optimization.

// Each task will auto retry 1 time if download fail.
queueSet.setAutoRetryTimes(1);

if (serial) {
     // Start downloading in serial order.
     queueSet.downloadSequentially(tasks);
     // If your tasks are not a list, invoke such following will more readable:
//      queueSet.downloadSequentially(
//              FileDownloader.getImpl().create(url).setPath(...),
//              FileDownloader.getImpl().create(url).addHeader(...,...),
//              FileDownloader.getImpl().create(url).setPath(...)
//      );
}

if (parallel) {
   // Start parallel download.
   queueSet.downloadTogether(tasks);
   // If your tasks are not a list, invoke such following will more readable:
//    queueSet.downloadTogether(
//            FileDownloader.getImpl().create(url).setPath(...),
//            FileDownloader.getImpl().create(url).setPath(...),
//            FileDownloader.getImpl().create(url).setSyncCallback(true)
//    );
}


queueSet.start();

The entire usage guide is available here : Wiki

Also, This is the question I've had asked in order to download multiple images using Picasso : Downloading images using Picasso creates incorrect images in cache, possible fix?