BaseAdapter 设置 notifyDataSetChanged 无效

额。。。。还没弄完。这里面有些问题。

经常遇到这个问题，令我倍感头疼。。。有时候会觉得莫名其妙。今天遇到了一个例子，意外解决了。

先看下适配器代码。

public class MenuAdapter extends BaseExpandableListAdapter {List<Pair<Integer, Class<? extends Activity>>> list = new ArrayList<Pair<Integer,Class<? extends Activity>>>();List<List<Pair<Integer, Class<? extends Activity>>>> listChild = new ArrayList<List<Pair<Integer, Class<? extends Activity>>>>();private LayoutInflater inflater;/****省略了若干行代码***/private int groupSelected,childSelected;public void setSelection(int groupId,int childId){this.groupSelected = groupId;this.childSelected = childId;notifyDataSetChanged();//我在此处通知了adapter 数据集改变。System.out.println(groupSelected+","+childSelected);}@Overridepublic View getGroupView(int groupPosition, boolean isExpanded,View convertView, ViewGroup parent) {convertView= inflater.inflate(R.layout.menu_item_group, null);TextView t = (TextView) convertView.findViewById(R.id.txt);Log.d("", groupPosition+",groupSelected:"+groupSelected);if(groupPosition == groupSelected){convertView.setBackgroundResource(scut.shengchuanglibrary.R.color.bg_menu_item_group_select);}t.setText(list.get(groupPosition).first);return convertView;}@Overridepublic View getChildView(int groupPosition, int childPosition,boolean isLastChild, View convertView, ViewGroup parent) {convertView= inflater.inflate(R.layout.menu_item_child, null);TextView t = (TextView) convertView.findViewById(R.id.txt);t.setText(listChild.get(groupPosition).get(childPosition).first);Log.d("", groupPosition+","+childPosition+",groupSelected:"+groupSelected+",childSelected:"+childSelected);if(groupPosition == groupSelected&& childPosition == childSelected){convertView.setBackgroundResource(scut.shengchuanglibrary.R.color.bg_menu_item_select);}return convertView;}@Overridepublic boolean isChildSelectable(int groupPosition, int childPosition) {// TODO Auto-generated method stubreturn true;}}

下面是调用setSelection 的代码片段：

private void initExpandListView(View view){final ExpandableListView listView = (ExpandableListView) view.findViewById(R.id.expandableListView1);listView.setChildIndicator(null);listView.setGroupIndicator(null);final MenuAdapter adapter = new MenuAdapter(this);listView.setAdapter(adapter);listView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {@Overridepublic boolean onChildClick(ExpandableListView parent, View v,int groupPosition, int childPosition, long id) {Pair<Integer, Class<? extends Activity >> pair = (Pair<Integer, Class<? extends Activity>>) listView.getExpandableListAdapter().getChild(groupPosition, childPosition);adapter.setSelection(groupPosition, childPosition);  // 在该函数中，调用了notifyDataSetChangedreturn false;}});listView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {@Overridepublic boolean onGroupClick(ExpandableListView parent, View v,int groupPosition, long id) {Pair<Integer, Class<? extends Activity >> pair = (Pair<Integer, Class<? extends Activity>>) listView.getExpandableListAdapter().getGroup(groupPosition);if(pair.first==R.string.menu_exit){android.os.Process.killProcess(android.os.Process.myPid());return false;}adapter.setSelection(groupPosition, 0);   // 在该函数中，调用了notifyDataSetChangedif(pair.second == null){return false;}return false;  //如果我返回true ，则，不会出现我想要的效果，点击后，item 换个背景颜色。}});}

在以上的代码中，如果在onGroupClickListener 返回true 。则即使我调用了notifyDataSetChanged 也没有任何效果。adapter 不会重新调用 getview 之类的。但是试了下返回false 则adapter 会立刻调用getview更新数据。

仔细看一下onGroupClick 的api说明。如果返回为true 则表示已经解决了此次click 事件。既然已经解决了，我想在之后的处理流程中，自然会把所有的操作的结束了。不会再去对整个ListView 进行修改。因为此次点击事件已经成功完成了。而更新数据，应该是在整个ongroupclick 事件完成之后的。

所以其实想想。很多时候，遇到notifyDataSetChanged 无效。或许是因为某些原因，把整个事件派发流给截断了。之后就就不再对listview 进行相关操作。而导致没有调用 getview。 所以遇到这种没有更新数据集的情况，可以去查看是否因为某些原因，listview 停止了事件派发。