Question

I have Asynctask in my activity. The problem is when I setText in onPostExecute() it gave me NullPointerException. the textview in a custom dialog XML. I tried to put the TextView variable as a global but it’s the same thing. The toast is working fine. This is my code:

private class LikeDislike extends AsyncTask<String, Integer, JSONObject> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected JSONObject doInBackground(String... params) {
            UserFunctions userFunction = new UserFunctions();
            JSONObject json;
            json = userFunction.likeDislike(params[0]);
            return json;
        }

        @Override
        protected void onPostExecute(JSONObject json) {
            super.onPostExecute(json);

            try {
                if (json.getString(KEY_SUCCESS) != null) {
                    //registerErrorMsg.setText("");
                    String res = json.getString(KEY_SUCCESS); 
                    if(Integer.parseInt(res) == 1){
                        String like = json.getString("like");
                        String disLike = json.getString("dislike");
                        TextView likeText = (TextView) findViewById(R.id.likenumber);
                        TextView dislikeText = (TextView) findViewById(R.id.dislikenumber);
                        likeText.setText(like);
                        dislikeText.setText(disLike);
                        //TODO
                    }else{      
                        Context context = getApplicationContext();
                        int duration = Toast.LENGTH_LONG;
                        Toast toast = Toast.makeText(context, "error in parsing", duration);
                        toast.show();
                    }
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
    }

Answer 1

You are saying the TextViews are in your Dialog then you have to call myDialog.findViewById() to get the views.
Otherwise findViewById() try to find it in your Activity.