how to get result from thread in android?

Question

I have a main class, a worker thread class and it separated. In main thread, I pass input to worker thread and ask for it to work. When it finish, I want it to send back result

Answer 1

Maybe you should try AsynTask, it is designed for just that:

 private class MyThread extends AsyncTask<Params, Progress, Result> {
     protected Long doInBackground(URL... urls) {
            // Calculate and return retulst
     }


     protected void onPostExecute(Long result) {
         // This is executed in main Thread, use the result
     }
 }  

You execute this thread like this:

new MyThread().execute(params, ...);

See http://developer.android.com/reference/android/os/AsyncTask.html

Answer 2

You can post a runnable to be executed on the main UI thread using the following code at the end of your thread's run() method:

MainActivity.this.runOnUiThread(new Runnable() {
    @Override
    public void run() {
        // TODO: modify the text view, other UI elements, etc.
    }
});

Answer 3

use AsyncTask instead to avoid any multi-threading issues example code:

private class DownloadWebPageTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
  String response = "";
  for (String url : urls) {
    DefaultHttpClient client = new DefaultHttpClient();
    HttpGet httpGet = new HttpGet(url);
    try {
      HttpResponse execute = client.execute(httpGet);
      InputStream content = execute.getEntity().getContent();

      BufferedReader buffer = new BufferedReader(new InputStreamReader(content));
      String s = "";
      while ((s = buffer.readLine()) != null) {
        response += s;
      }

    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  return response;
}
@Override
protected void onPostExecute(String result) {
  textView.setText(result);
}}

Use it as an inner class in your adapter Also you can use many APIs like volly if you are into networking.