How To Prevent Ui Lag When Updating Notification While Downloading File?

I am currently using AsyncTask to download a large file in the background within my app, currently the download progress is shown as a ProgressDialog which is updated via onProgres

Solution 1:

so how could I go about changing the background code to call publishProgress only every second

I have done this before for an upload function that showed the % in a Notification, but same exact idea. Have your AsyncTask keep track of what percentDone the download is, and ONLY call publishProgress when percentDone changes. That way, you will only ever call publishProgress when the % downloaded changes, and the Notification therefore needs to update. This should resolve the UI lag.

I was writing this up as my suggested implementation, sounds like the OP already got it working. But maybe this will help someone else in the future:

byte data[] = newbyte[1024];
    long total = 0;
    int count, latestPercentDone;
    int percentDone = -1;
    while ((count = input.read(data)) != -1) {
        total += count;
        latestPercentDone = (int) Math.round(total / fileLength * 100.0);
        if (percentDone != latestPercentDone) {
            percentDone = latestPercentDone;
            publishProgress(percentDone);
        }
        output.write(data, 0, count);
    }

Solution 2:

I really liked your approach to it! I found that changing the code to the following made my progressbar update correctly. I had some issues while using math.round().

latestPercentDone = (int) ((dataBytesWritten / (float) totalSize) * 100);
    if (percentDone != latestPercentDone) {
    percentDone = latestPercentDone;
    publishProgress(percentDone);
    }