在使用ListView的时候，需要添加一个header，结果报异常了, ClassCastException。
代码如下：
mHeaderView = inflater.inflate(R.layout.test_header, container, false);
mListView.addHeaderView(mHeaderView);
执行后报错，ClassCastException。
java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams
at android.widget.ListView.clearRecycledState(ListView.java:582)
at android.widget.ListView.resetList(ListView.java:568)
at android.widget.ListView.setAdapter(ListView.java:500)
栈信息很明确是clearRecycledState抛出来的，再来看代码。
void resetList() {
// The parent's resetList() will remove all views from the layout so we need to
// cleanup the state of our footers and headers
clearRecycledState(mHeaderViewInfos);
clearRecycledState(mFooterViewInfos);
super.resetList();
mLayoutMode = LAYOUT_NORMAL;
}
private void clearRecycledState(ArrayList<FixedViewInfo> infos) {
if (infos != null) {
final int count = infos.size();
for (int i = 0; i < count; i++) {
final View child = infos.get(i).view;
final LayoutParams p = (LayoutParams) child.getLayoutParams();
if (p != null) {
p.recycledHeaderFooter = false;
}
}
}
}
clearRecycledState中要求headerview的LayoutParams要强转为android.widget.AbsListView$LayoutParams类型。 而我们的mHeaderView是用LayoutInflater初始化的。
查看方法public View inflate(int resource, ViewGroup root, boolean attachToRoot)的说明。
/**
* Inflate a new view hierarchy from the specified xml resource. Throws
* {@link InflateException} if there is an error.
*
* @param resource ID for an XML layout resource to load (e.g.,
* <code>R.layout.main_page</code>)
* @param root Optional view to be the parent of the generated hierarchy (if
* <em>attachToRoot</em> is true), or else simply an object that
* provides a set of LayoutParams values for root of the returned
* hierarchy (if <em>attachToRoot</em> is false.)
* @param attachToRoot Whether the inflated hierarchy should be attached to
* the root parameter? If false, root is only used to create the
* correct subclass of LayoutParams for the root view in the XML.
* @return The root View of the inflated hierarchy. If root was supplied and
* attachToRoot is true, this is root; otherwise it is the root of
* the inflated XML file.
*/
public View inflate(int resource, ViewGroup root, boolean attachToRoot) {
由此可以看出，由于第二个参数我们给的是一个具体的layout，第三个参数给的是false，所以inflater按照第二个参数的layout给初始化了。 修改代码为：
mHeaderView = inflater.inflate(R.layout.hotshare_huati_tab, null);
即可。