Question

i am using a custom listview with images in my app
and loading all data from a json url.

i have created a onscrollistener()

which automatically add data below the current data when user scrolls to the bottom of the listview.

But when my data is loading whole listview freezes for 2-3 sec.

I dont know whats wrong??

here is my code for AsyncTask

private class BackgroundLoadMore extends AsyncTask<Void, Void, Void> {

          @Override
            protected void onPreExecute() {
                // Showing progress dialog before sending http request


            }

        protected Void doInBackground(Void... unused) {
            runOnUiThread(new Runnable() {
                public void run() {

                    LoadData();


                            list.setOnScrollListener(new EndlessScrollListener());
                }
            });
            return (null);
        }

        protected void onPostExecute(Void unused) {
            // On completing background task
            // closing progress dialog etc,.


        }

Answer 1

You must be fetching the json data from url in main UI thread. This blocks the UI from being updated by system, and hence the freeze. Use AsyncTask to do such network tasks in background.

LoadData() should be called in a background thread, which is asynctask’s doInBackground(). Your call runOnUIThread puts it back on the UI thread, and that you dont want. remove the runOnUIThread call from asynctask.

     protected Void doInBackground(Void... unused) {
        LoadData();

        return (null);
    }

   protected void onPostExecute(Void unused) {
        // On completing background task
        // closing progress dialog etc,.

        list.setOnScrollListener(new EndlessScrollListener());

    }