Android版手风琴(ExpandableListView)

先看效果，过瘾一番。

 

 源码下载：https://files.cnblogs.com/salam/WidgetDemo.rar

　　

　　ExpandableListView是Android中的手风琴，本人感觉效果相当棒。

　　一、ExpandableListView介绍

　　　　一个垂直滚动的显示两个级别（Child,Group）列表项的视图，列表项来自ExpandableListAdapter 。组可以单独展开。

　　1.重要方法

　　　　　　expandGroup(int groupPos) :在分组列表视图中展开一组，

　　　　　　setSelectedGroup(int groupPosition) ：设置选择指定的组。

　　　　　　setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup) ：设置选择指定的子项。

　　　　　　getPackedPositionGroup(long packedPosition) ：返回所选择的组

　　　　　　getPackedPositionForChild(int groupPosition, int childPosition) ：返回所选择的子项

　　　　　　getPackedPositionType(long packedPosition) ：返回所选择项的类型（Child,Group）

　　　　　　isGroupExpanded(int groupPosition) :判断此组是否展开

　　2.代码：

ExpandableListContextMenuInfo menuInfo=(ExpandableListContextMenuInfo)item.getMenuInfo();
  String title=((TextView)menuInfo.targetView).getText().toString();
  int type=ExpandableListView.getPackedPositionType(menuInfo.packedPosition);
  
  if (type==ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
  int groupPos =ExpandableListView.getPackedPositionGroup(menuInfo.packedPosition);
  int childPos =ExpandableListView.getPackedPositionChild(menuInfo.packedPosition);

二、ExpandableListAdapter

　　　　一个接口，将基础数据链接到一个ExpandableListView。此接口的实施将提供访问Child的数据（由组分类），并实例化的Child和Group。

　　1.重要方法

　　　　getChildId(int groupPosition, int childPosition) 获取与在给定组给予孩子相关的数据。

　　　　getChildrenCount(int groupPosition) 返回在指定Group的Child数目。

　　2.代码

 public class MyExpandableListAdapter extends BaseExpandableListAdapter {
         // Sample data set.  children[i] contains the children (String[]) for groups[i].
         public String[] groups = { "我的好友", "新疆同学", "亲戚", "同事" };
         public String[][] children = {
                 { "胡算林", "张俊峰", "王志军", "二人" },
                 { "李秀婷", "蔡乔", "别高", "余音" },
                 { "摊派新", "张爱明" },
                 { "马超", "司道光" }
         };
        
         public Object getChild(int groupPosition, int childPosition) {
             return children[groupPosition][childPosition];
         }

         public long getChildId(int groupPosition, int childPosition) {
             return childPosition;
         }

         public int getChildrenCount(int groupPosition) {
             return children[groupPosition].length;
         }

         public TextView getGenericView() {
             // Layout parameters for the ExpandableListView
             AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
                     ViewGroup.LayoutParams.MATCH_PARENT, 64);

             TextView textView = new TextView(ExpandableListDemo.this);
             textView.setLayoutParams(lp);
             // Center the text vertically
             textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
             // Set the text starting position
             textView.setPadding(36, 0, 0, 0);
             return textView;
         }
        
         public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
                 View convertView, ViewGroup parent) {
             TextView textView = getGenericView();
             textView.setText(getChild(groupPosition, childPosition).toString());
             return textView;
         }

         public Object getGroup(int groupPosition) {
             return groups[groupPosition];
         }

         public int getGroupCount() {
             return groups.length;
         }

         public long getGroupId(int groupPosition) {
             return groupPosition;
         }

         public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
                 ViewGroup parent) {
             TextView textView = getGenericView();
             textView.setText(getGroup(groupPosition).toString());
             return textView;
         }

         public boolean isChildSelectable(int groupPosition, int childPosition) {
             return true;
         }

         public boolean hasStableIds() {
             return true;
         }

     }