Android Spinner onItemSelected未在Fragment中调用

Question

我有一个调用多个片段的活动。在其中一个片段中，我正在尝试以编程方式创建一个对话框微调器并将其添加到菜单选项(在工具栏中(。我设法让它工作(至少视图显示(，但 onItemSelected 它没有被调用。

我的代码：

public class NewsFeed extends Fragment {
private static final String TAG = "tag";
private String tag;
private ArrayAdapter<New> newsadapter;
private ArrayAdapter<Tag> tagsadapter;
private Spinner spinner;
public NewsFeed() {
    setHasOptionsMenu(true);
}
public static NewsFeed newInstance(String tag) {
    NewsFeed fragment = new NewsFeed();
    Bundle args = new Bundle();
    args.putString(TAG, tag);
    fragment.setArguments(args);
    return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        tag = getArguments().getString(TAG);
    }
    setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    getActivity().setTitle(tag);
    NavigationView activitynav = (NavigationView) getActivity().findViewById(R.id.nav_view);
    BottomNavigationView activitybuttomnav = (BottomNavigationView) getActivity().findViewById(R.id.navigation);
    activitynav.setCheckedItem(R.id.nav_news);
    activitybuttomnav.getMenu().getItem(1).setChecked(true);
    View v = inflater.inflate(R.layout.fragment_news_feed, container, false);
    //Spinner related code      
    tagsadapter = new TagsAdapter(getActivity(), android.R.layout.simple_spinner_item, (ArrayList<Tag>) ApplicationData.tags);
    spinner = new Spinner(getActivity(), Spinner.MODE_DIALOG);
    tagsadapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setPrompt("Filtrar por categoria:");
    spinner.setAdapter(tagsadapter);
    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        }
        @Override
        public void onNothingSelected(AdapterView<?> parent) {
        }
    });
    newsadapter = new NewsAdapter(getActivity().getApplicationContext(), 0, (ArrayList<New>) ApplicationData.news);
    ListView listview = (ListView) v.findViewById(R.id.listview);
    listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapter, View view, int position, long id) {
            FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
            NewsDisplay nd = NewsDisplay.newInstance(tag, ApplicationData.news.get(position).getNewsUrl());
            ft.addToBackStack(null);
            ft.replace(R.id.fragmentcontent, nd).commit();
        }
    });
    listview.setAdapter(newsadapter);
    return v;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.main, menu);
    super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.filter_category) {
         //For showing the spinner
        spinner.performClick();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

}

已经尝试过：

使新闻源实现 OnItemSelectedListener。

在 SetOnItemSelectedListener 中创建 OnItemSelectedListener 对象。

你能给我一些帮助吗？这可能与此片段有关，工具栏位于活动中。

Answer 1

动态

创建的Spinner(private val popupSpinner: Spinner by lazy { Spinner(this, Spinner.MODE_DIALOG) }(需要具有分配的父视图。如果没有它，则出于某种原因永远不会调用OnItemSelected。

我写这个黑客来缓解这个问题。添加到父视图并将其隐藏。确保不要在 onResume(( 方法和类似的方法中运行它。

findViewById<ViewGroup>(android.R.id.content).addView(popupSpinner)
popupSpinner.visibility = View.INVISIBLE

附言。有些人可能会认为这个问题没有答案。但在评论中，作者本人找到了解决方案。