Filling a ListView through an array

I have an android application that, in a loop from a json line, takes the necessary data and stuffs it into a variable. After that, you need to fill the ListView array of these variables. I fill the array in the same loop, and after it is completed, I create an adapter and assign it to my ListView . But nothing comes out ... Here is the code:

 JSONArray jsonarray = new JSONArray(jj); String[] val = new String[20]; //необходимый мне массив int i; //Сам цикл: for (i = 0; i < jsonarray.length(); i++) { JSONObject obj = jsonarray.getJSONObject(i); String lesson = obj.getString("lesson"); String task = obj.getString("task"); //Вот моя переменная "data" String data = lesson + ": " + task; //Которую я запихиваю в массив в соответствии с порядком (счетчик i) val[i] = data; } //И дальше делаем адаптер и в listView его: ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mass); lv.setAdapter(adapter); //lv - listView 

ListView initialized, checked - everything is fine ... Help please who than can ..