Downloading a file by using a service

Issue

To download some files on lots of activities, I thought it will be much better to integrate all the same codes into one activity like (DownloadFiles.class), but here is the problem. I have to get a progress value into my main activity (SetupActivity.class), it is impossible to do that using AsyncTask. The original code was:

private class DownloadFiles extends AsyncTask<String, Integer, String> {
    private Context context;
    private PowerManager.WakeLock mWakeLock;

    public DownloadFiles(Context context) {
        this.context = context;
    }
    @Override
    protected String doInBackground(String... input_value) {
        InputStream input = null;
        OutputStream output = null;
        HttpURLConnection connection = null;
        try {
            URL url = new URL(input_value[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            int fileLength = connection.getContentLength();
            input = connection.getInputStream();
            output = new FileOutputStream(new File(input_value[1]));
            byte data[] = new byte[4096];
            long total = 0;
            int count;
            while ((count = input.read(data)) != -1) {
                if (isCancelled()) {
                    input.close();
                    return null;
                }
                total += count;
                if (fileLength > 0)
                    publishProgress((int) (total * 100 / fileLength));
                output.write(data, 0, count);
            }
        } catch (Exception e) {
            return e.toString();
        } finally {
            try {
                if (output != null) output.close();
                if (input != null) input.close();
            } catch (IOException ignored){
                ignored.printStackTrace();
            }
            return "Download Complete.";
        }
    }
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
        mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                getClass().getName());
        mWakeLock.acquire();
    }
    @Override
    protected void onProgressUpdate(Integer... progress) {
        super.onProgressUpdate(progress);
    }
    @Override
    protected void onPostExecute(String result) {
        mWakeLock.release();
        if (!result.equals("Download Complete.")) {

        } else {

        }
    }
}

It was unable to use onProgressUpdate to handle other activities' progressbar. The reason why I am not using ProgressDialog is since it is deprecated, it is much better to use the Progressbar which doesn't prevent user from interacting with user interfaces.

I heard that using services is one of the answers, but there are no ways to update progressbar with my knowledge.

Solution

You can also pass a callback value to the AsyncTask like this:

private class DownloadFiles extends AsyncTask<String, Integer, String> {
private Context context;
private PowerManager.WakeLock mWakeLock;
private ProgressCallback mProgressCallback

public DownloadFiles(Context context, ProgressCallback callback) {
    this.context = context;
    mProgressCallback = callback
}

Then you create an interface like this:

public interface ProgressCallback{ 

   void onProgressUpdate(int percentComplete);

Have every activity or fragment which needs to show the progress implement this interface and then you can call from onProgressupdate in the asyncTask:

@Override
protected void onProgressUpdate(Integer... progress) {
        super.onProgressUpdate(progress);
        mProgressCallback.onProgressUpdate(progress[0])
    }

You can tweak the interface and method whichever way you like.

Answered By - KvdLingen