listview getChildAt（）返回null(listview getChildAt() Return null)

我一直在研究一个android项目并陷入了一个问题。我GOOGLE了它，但没有找到答案。在我的项目中，有一个名为viewsurahfragment的片段，它包含一个listview，其ID是lv_showquran 。

我想突出显示指定索引处的列表视图。我使用listview.getchildat（）但它返回null值。这是viewsurahfragment的代码。不相关的功能是有效的。

public class ViewSurahFragment extends Fragment { private ListView listView; private int currentSurah; private String surahName; private DatabaseHelper databaseHelper; private ArrayAdapter<String> arrayAdapter; @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); // this.listView = (ListView) getActivity().findViewById(R.id.lv_showQuran); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); this.listView = (ListView) getActivity().findViewById(R.id.lv_showQuran); } private void displayAyas() { String[] values = this.getSurahAyas(); this.listView.setItemsCanFocus(true); this.arrayAdapter = new ArrayAdapter<>(this.getActivity().getApplicationContext(), R.layout.layout_surah_ayah, values); this.listView.setAdapter(this.arrayAdapter); this.listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { } }); registerForContextMenu(this.listView); } public void highlightAyah(int ayahNum) { TextView view = (TextView) this.listView.getChildAt(ayahNum - 1); Log.i("ViewSurahFragment", "List View Child Counts Are: " + this.listView.getChildCount()); if(view == null) Log.i("ViewSurahFragment", "view is null"); } }

不要onactivitycreated我是否在onactivitycreated或onviewcreated使用下面的代码行，它在highlightayah函数中调用listview.getchildat（）时返回null。

this.listView = (ListView) getActivity().findViewById(R.id.lv_showQuran);

我也试图做下面的事情，但它也不适合我。

ListView view = (ListView) getActivity().findViewById(R.id.lv_showQuran); TextView v = (TextView) view.getChildAt(ayahNum); Log.i("ViewSurahFragment", "List View Child Counts Are: " + view.getChildCount()); if(v == null) Log.i("ViewSurahFragment", "view is null");

但对我来说有趣的是getchildviewcount() return 0在我使用的解决方案中getchildviewcount() return 0 ，但项目显示在列表视图中。任何人都可以告诉我我犯了什么错误。预先感谢您的帮助。

I have been working on an android project and stuck in a problem. I googled it but found no answer. In my project, there is a fragment named viewsurahfragment and it contains a listview whose id is lv_showquran.

I want to highlight the view of the listview at specified index. I am using listview.getchildat() but it return null value. Here is the code for viewsurahfragment. Irrelevant functions are emited.

public class ViewSurahFragment extends Fragment { private ListView listView; private int currentSurah; private String surahName; private DatabaseHelper databaseHelper; private ArrayAdapter<String> arrayAdapter; @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); // this.listView = (ListView) getActivity().findViewById(R.id.lv_showQuran); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); this.listView = (ListView) getActivity().findViewById(R.id.lv_showQuran); } private void displayAyas() { String[] values = this.getSurahAyas(); this.listView.setItemsCanFocus(true); this.arrayAdapter = new ArrayAdapter<>(this.getActivity().getApplicationContext(), R.layout.layout_surah_ayah, values); this.listView.setAdapter(this.arrayAdapter); this.listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { } }); registerForContextMenu(this.listView); } public void highlightAyah(int ayahNum) { TextView view = (TextView) this.listView.getChildAt(ayahNum - 1); Log.i("ViewSurahFragment", "List View Child Counts Are: " + this.listView.getChildCount()); if(view == null) Log.i("ViewSurahFragment", "view is null"); } }

Don't metter whether i used following line of code either in onactivitycreated or in onviewcreated, it returned null on calling listview.getchildat() in highlightayah function.

this.listView = (ListView) getActivity().findViewById(R.id.lv_showQuran);

I also tried to do following, but it also didn't work for me.

ListView view = (ListView) getActivity().findViewById(R.id.lv_showQuran); TextView v = (TextView) view.getChildAt(ayahNum); Log.i("ViewSurahFragment", "List View Child Counts Are: " + view.getChildCount()); if(v == null) Log.i("ViewSurahFragment", "view is null");

But the interesting thing for me is that getchildviewcount() return 0 in either solutions i used, but items are displayed in the listview. Can anybody please tell me where i'm doing mistake. Thanks in advance for helping.