Android app and SQLiteOpenHelper - Refresh after adding a new task

This is my class that stores todolist. I would like to add it to record when you add a new task to refresh the entire list, and you can add a new task.

import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.text.Editable;
    import android.text.TextWatcher;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.ListView;
    import android.widget.TabHost;
    import android.widget.TextView;
    import android.widget.Toast;

    import org.androidannotations.annotations.EFragment;

    import java.util.ArrayList;
    import java.util.List;

    import pl.edu.ug.aib.studentizerApp.R;
    import pl.edu.ug.aib.studentizerApp.todoList.DatabaseHandler;
    import pl.edu.ug.aib.studentizerApp.todoList.Task;


    @EFragment(R.layout.fragment_todo)
    public class TODOFragment extends Fragment {

        EditText zadanieTxt, opisTxt, dataTxt, adresTxt;
        List<Task> Tasks = new ArrayList<Task>();
        ListView TaskListView;
        DatabaseHandler dbHandler;
        @Override
        public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
            return inflater.inflate(R.layout.fragment_todo, container, false);
        }
        @Override
        public void onStart() {
            super.onStart();


            zadanieTxt = (EditText) getView().findViewById(R.id.txtZadanie);
            opisTxt = (EditText) getView().findViewById(R.id.txtOpis);
            dataTxt = (EditText) getView().findViewById(R.id.txtData);
            adresTxt = (EditText) getView().findViewById(R.id.txtAdres);
            TaskListView = (ListView) getView().findViewById(R.id.listView);
            dbHandler = new DatabaseHandler(getActivity().getApplicationContext());

            TabHost tabHost = (TabHost) getView().findViewById(R.id.baner);

            tabHost.setup();

            TabHost.TabSpec tabSpec = tabHost.newTabSpec("Dodaj zadanie");
            tabSpec.setContent(R.id.tabZadanie);
            tabSpec.setIndicator("Dodaj Zadanie");
            tabHost.addTab(tabSpec);

            tabSpec = tabHost.newTabSpec("lista");
            tabSpec.setContent(R.id.tabListaZadan);
            tabSpec.setIndicator("Lista");
            tabHost.addTab(tabSpec);

            final Button addBtn = (Button) getView().findViewById(R.id.btnAdd);
            addBtn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Task task = new Task(dbHandler.getTaskCount(), String.valueOf(zadanieTxt.getText()), String.valueOf(opisTxt.getText()), String.valueOf(dataTxt.getText()), String.valueOf(adresTxt.getText()));
                    if (!taskExists(task)) {
                        dbHandler.createZadanie(task);
                        Tasks.add(task);
                        Toast.makeText(getActivity().getApplicationContext(), String.valueOf(zadanieTxt.getText()) + " zostało dodane do listy zadań!", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    Toast.makeText(getActivity().getApplicationContext(), String.valueOf(zadanieTxt.getText()) + " Zadanie już istnieje", Toast.LENGTH_SHORT).show();
                }
            });

            zadanieTxt.addTextChangedListener(new TextWatcher() {
                @Override
                public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {

                }

                @Override
                public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
                    addBtn.setEnabled(String.valueOf(zadanieTxt.getText()).trim().length() > 0);
                }

                @Override
                public void afterTextChanged(Editable editable) {

                }
            });



            if (dbHandler.getTaskCount() != 0)
                Tasks.addAll(dbHandler.getAllTasks());

            populateList();
        }

        private boolean taskExists(Task task) {
            String zadanie = task.getZadanie();
            int taskCount = Tasks.size();

            for (int i = 0; i < taskCount; i++) {
                if (zadanie.compareToIgnoreCase(Tasks.get(i).getZadanie()) == 0)
                    return true;
            }
            return false;
        }


        private void populateList() {
            ArrayAdapter<Task> adapter = new TaskListAdapter();
            TaskListView.setAdapter(adapter);
        }

        private class TaskListAdapter extends ArrayAdapter<Task> {
            public TaskListAdapter()
            {

                super (TODOFragment.this.getActivity(), R.layout.listview_item, Tasks);
            }

            @Override
            public View getView(int position, View view, ViewGroup parent) {
                if (view == null)
                    view = getActivity().getLayoutInflater().inflate(R.layout.listview_item, parent, false);

                Task currentTask = Tasks.get(position);

                TextView zadanie = (TextView) view.findViewById(R.id.zadanie);
                zadanie.setText(currentTask.getZadanie());
                TextView opis = (TextView) view.findViewById(R.id.opis);
                opis.setText(currentTask.getOpis());
                TextView data = (TextView) view.findViewById(R.id.data);
                data.setText(currentTask.getData());
                TextView adres = (TextView) view.findViewById(R.id.adres);
                adres.setText(currentTask.getAdres());

                return view;
            }
        }



    }

Do any of you can give me to write what and where would you add?