Ytukyg

noobie here. I have a custum ArrayAdapter with questions and answers. When one list item is longClicked, it gets removed. Now I want to save the new state of the ArrayList with the removed item, so if you go to another tab in the app and then return you will have only the remaining questions.
I looked online and found something that looks like what I need, but I can't see why it won't work.

public class OnePointQuestion extends AppCompatActivity {

ArrayList<Question> TheQuestion;

String key = "ABCD";



@Override

protected void onCreate(@Nullable Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.list);



    if(TheQuestion == null){

        createList();

    }else{

        getArrayList(key);

    }



    final MyAdapter adapter = new MyAdapter(this, TheQuestion);

    ListView listView = findViewById(R.id.list);

    listView.setAdapter(adapter);



    //When the list item is clicked

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        @Override

        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            //Identify the current question

            Question currentQuestion = TheQuestion.get(position);



            //Send the answer to a second page to be shown

            Intent i = new Intent(OnePointQuestion.this, TheAnswer.class);

            i.putExtra("TheAnswer", currentQuestion.getAnswer());

            startActivity(i);

        }

    });



    //When the list item is long clicked

    listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {

        @Override

        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {

            //Identify the current question

            Question currentQuestion = TheQuestion.get(position);

            //Remove this element of the list

            TheQuestion.remove(currentQuestion);

            adapter.notifyDataSetChanged();

            Toast.makeText(OnePointQuestion.this, "Urmatoarea intrebare", Toast.LENGTH_SHORT).show();

            return true;

        }

    });

}



//Save the ArrayList

public void saveArrayList(ArrayList<Question> list, String key){

    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(OnePointQuestion.this);

    SharedPreferences.Editor editor = prefs.edit();

    Gson gson = new Gson();

    String json = gson.toJson(list);

    editor.putString(key, json);

    editor.apply();     // This line is IMPORTANT !!!

    Toast.makeText(OnePointQuestion.this, "Saved", Toast.LENGTH_SHORT).show();

}



//Load the ArrayList

public ArrayList<Question> getArrayList(String key){

    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(OnePointQuestion.this);

    Gson gson = new Gson();

    String json = prefs.getString(key, null);

    Type type = new TypeToken<ArrayList<Question>>() {}.getType();

    Toast.makeText(OnePointQuestion.this, "Loaded", Toast.LENGTH_SHORT).show();

    return gson.fromJson(json, type);

}



//Load the ArrayList when the app gets to the OnStart

@Override

protected void onStart() {

    super.onStart();

    getArrayList(key);

}





@Override

protected void onPause() {

    super.onPause();

    saveArrayList(TheQuestion, key);

}





public void createList(){

    //Create the list of questions

    TheQuestion = new ArrayList<>();

    TheQuestion.add(new Question("Cum te cheama?", "Irelevant"));

    TheQuestion.add(new Question("Cati ani ai?", "Prea multi"));

    TheQuestion.add(new Question("De ce ai dat la Poli", "Asta ma intreb si eu"));



}

}

The "save" and "load" methods I'm trying to use are near the end.
If you can tell me what I am doing wrong, I would appreciate it, thanks :)

Move getArrayList(key); to onResume() method.

@Override

protected void onResume() {

    super.onResume();

    getArrayList(key);

}

see the life cycle: