android - fragment 内的微调器

Question

我正在创建一个简单的 Android 游戏应用程序，但我在 fragment 中的微调器中遇到了一些问题。我尝试了一些解决方案，但我的应用程序仍然崩溃。有人能帮我吗？非常感谢。

 public class SlotMachineFragmentOne extends Fragment {

 Spinner dropdown;

 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.activity_slotmachine_fragment_one, container, false);

    initspinnerfooter();
    dropdown = rootView.findViewById(R.id.spinner);

    return rootView;
}

private void initspinnerfooter() {
    String[] items = new String[]{
            "Choose apple", "Choose boy", " Choose cat", "Choose dog", 
    };

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_item, items);
    dropdown.setAdapter(adapter);
    dropdown.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            Log.v("item", (String) parent.getItemAtPosition(position));
            ((TextView) parent.getChildAt(0)).setTextColor(Color.WHITE);
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            // TODO Auto-generated method stub
        }
    });
}   }

Answer 1

在 dropdown = rootView.findViewById(R.id.spinner); 之后调用 initspinnerfooter();

像这样:

    @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.activity_slotmachine_fragment_one, container, false);

    dropdown = rootView.findViewById(R.id.spinner);
    initspinnerfooter();

    return rootView;
}