Android ListView元素未被选中

我有一个ListViewFragment类，它被配置为选择单模式。我正在使用自定义游标适配器填充listView。问题是，当我从LV中选择某个内容时，它不会被蓝色背景突出显示。但是，只有文本变为粗体。代码：

public class CategoryFragment extends ListFragment{

int lastPosition;
DatabaseControl db;
OnCategorySelectedListener callBack;
CategoryCursorAdapter cursorInstance;
public interface OnCategorySelectedListener{

    public void onCategorySelected(int categoryName);   
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    db=new DatabaseControl(this.getActivity());
    db.open();
    getListView().setFastScrollEnabled(true);
    cursorInstance=new CategoryCursorAdapter(getActivity(), db.getCategoryCursor(""), CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER, "category_name",0, db);
    getListView().setAdapter(cursorInstance);

    getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
    this.setListShown(true);

    this.getListView().setOnItemLongClickListener(listViewLongClick);
    if(savedInstanceState!=null)
        getListView().setItemChecked(savedInstanceState.getInt("position"), true);

}




@Override
public void onAttach(Activity activity) {
    // TODO Auto-generated method stub
    super.onAttach(activity);
    try{
        callBack=(OnCategorySelectedListener) activity;
    }

    catch(ClassCastException e){

        throw new ClassCastException(activity.toString()+" must implement OnCategorySelectedListener");
    }
}


@Override
public void onSaveInstanceState(Bundle outState) {
    // TODO Auto-generated method stub
    super.onSaveInstanceState(outState);
    outState.putInt("position", lastPosition);

}

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按照以下步骤创建ListView选择器

• 首先，您必须在drawable文件夹中为ListView行创建一个选择器

list\u selector.xml

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您还可以检查我的

是否创建了列表选择器？否。如何设置？请给我举个例子

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
   <item android:drawable="@android:color/white" android:state_activated="true"/>
   <item android:drawable="@android:color/black"/>
</selector>

  mListView = (ListView) findViewById(R.id.listView);
  mListView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
  MyAdapter mAdapter = new MyAdapter();
  mListView.setAdapter(mAdapter);
  mListView.setSelection(0);         // setting 0th position selected by default
  mListView.setItemChecked(0, true);