Question

I have a main activity where I create an adapter for a arraylist data.
I read the news from a website using a separate thread with Jsoup.

In onCreate() i have

this.newsItemAdapter = new NewsItemAdapter(this, 
                       R.layout.newsitem_row,NewsItemAdapter.getAllNews()); 
parseThread.start();
this.newsItemAdapter.notifyDataSetChanged();

When i read from the adapter, i get empty list. This is because the thread is not completed yet. Any idea as to how i should proceed?

I cannot do notifyDataSetChanged inside my thread because it is not the owner of the adapter.

Answer 1

You need to notify after the seperate thread finishes, and invoke notifyDataSet on UI-thread, one possible method is to use handler,

you can define a handler in activity, invoke notifyDataSet change in handleMessage, such as

handler = new android.os.Handler() {
        @Override
        public void handleMessage(Message msg) {
            newsItemAdapter.notifyDataSetChanged();
        }
}

and in the thread run method, you need to send a message to the handler,

public void run() {
   // add this to the end
   Message msg = new Message()
   handler.sendMessage(msg);
}

or else you can use AsyncTask instead of seperate thread, use jsoup in task’s doInBackground method, and notifyDataSet in onPostExecute.

The handler document is http://developer.android.com/reference/android/os/Handler.html, and AsyncTask’s is http://developer.android.com/reference/android/os/AsyncTask.html.