WheelView设置焦点监听无效

移除WheelView的根布局和父布局的焦之后，再给WheelView设置setFocusable(true)、setFocusableInTouchMode(true)、setOnFocusChangeListener，但是onFocusChange中依旧监听不到焦点事件。
代码如下：
// 年
wv_year = (WheelView) view.findViewById(R.id.year);
wv_year.setAdapter(new ArrayWheelAdapter(ChinaDate.getYears(startYear, endYear)));// 设置"年"的显示数据
wv_year.setLabel("");// 添加文字
wv_year.setCurrentItem(year - startYear);// 初始化时显示的数据
wv_year.setGravity(gravity);
wv_year.setClickable(true);
wv_year.setFocusable(true);
wv_year.setFocusableInTouchMode(true);
wv_year.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
Log.i(TAG," onFocusChange "+hasFocus);
}
});