How to update the UI during the doInBackground portion of a thread?

Question

I have a time consuming task that is taking place in the doInBackground() method, but from within that method, I want to be able to update the progressDialog with percentage data. How can I do this?

    class GetDataTask extends AsyncTask<Void, Void, Void> {     

    @Override
    protected void onPreExecute()
    {
        mProgressDialog = ProgressDialog.show(getActivity(),Constants.APP_NAME,"Getting data", true);
    }

    @Override
    protected Void doInBackground(Void... params)
    {
        //go get data, update mProgressDialog
        return null;
    }

    @Override
    protected void onPostExecute(Void res)
    {           

    }
}

score 2 · Answer 1 · edited May 23 '17 at 11:48

2

Override the onProgressUpdate() method like this:

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

and publish the progress with

publishProgress((int) (total * 100 / fileLength));

Try to refer to this link

edited May 23 '17 at 11:48

Community

1
1

answered Jul 26 '12 at 01:29

K_Anas

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score 0 · Accepted Answer · answered Jul 26 '12 at 01:28

AsyncTask has method onProgressUpdate(Integer...) that you can call each iteration for example or each time a progress is done during doInBackground() by calling publishProgress().

Refer to the docs for more details

Note that the second parameter is the progress variable

class GetDataTask extends AsyncTask<Void, String, Void> {     

    @Override
    protected void onPreExecute()
    {
        mProgressDialog = ProgressDialog.show(getActivity(),Constants.APP_NAME,"Getting data", true);
    }

    @Override
    protected Void doInBackground(Void... params)
    {
        publishProgress(""+(int)count);
        return null;
    }

    protected void onProgressUpdate(String... progress) {
        /**
         * Sets current progress on ProgressDialog
         */
        mProgressDialog.setProgress(Integer.parseInt(progress[0]));
    }

    @Override
    protected void onPostExecute(Void res)
    {           

    }
}

but how does AsyncTask know how far along it is, what is the measuring stick so to speak? — user1154644, Jul 26 '12 at 01:40
measuring unit? you can do it whatever you like, like the `alreadydownloaded/sizeoffile`, simple `43/100 %`, whatever you want it to display and update :) — silentw, Jul 26 '12 at 16:46

How to update the UI during the doInBackground portion of a thread?

2 Answers2