Fragment안에 있는 listView의 onItemClick을 통해 new Activity를 열려고 하는데 안됩니다. [closed]

Question

public class Fragment1 extends Fragment {
    public static ListView listView;
    public static DatabaseHelper dbHelper;
    public static Adapter adapter;
    public static ArrayList<Item> arrayList=new ArrayList<Item>();
    public static ArrayList<Item> arrayList2 = new ArrayList<Item>();

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        final View v = inflater.inflate(R.layout.fragment1_layout, container, false);

        DBInsert();

        adapter = new Adapter(getActivity(), R.layout.custom_list_item, arrayList);
        listView = (ListView) v.findViewById(R.id.listOfItems);
        listView.setAdapter(adapter);
        adapter.notifyDataSetChanged();

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent i = new Intent(getActivity(), Calendar.class);
                startActivity(i);
            }
        });

        return v;
    }

Toast로 테스트 해봤을때 작동은 잘됐습니다. 근데 Activity를 열려고 하면 app이 종료됩니다.. 

혹시 getActivity말고 다른걸 넣어야 할까요?