Android：ExpandableListView 的使用
一、简介
ExpandableListView 是 ListView 的子类，它是在普通的 ListView 的基础上进行了扩展，它把应用中的列表项分组，每个分组里又可包含多个列表项。
ExpandableListView 的用法与 ListView 的用法十分类似，只是 ExpandableListView 的列表项由 ExpandableListAdapter 提供。
1.实现 ExpandableListAdapter 的三种常用方式：
(1)扩展 BaseExpandableListAdapter 实现 ExpandableListAdapter;
(2)使用 SimpleExpandableListAdapter 将两个 List 集合包装成 ExpandableListAdapter;
(3)使用 SimpleCursorTreeAdapter 将 Cursor 中的数据包装成 SimpleExpandableListAdapter
2.ExpandableListView 常用的 XML 属性
(1) 组列表项
android:groupIndicator //显示在组列表项旁边的 Drawable 对象
设置组列表项的边界符
android:indicatorEnd
android:indicatorLeft
android:indicatorRight
android:indicatorStart
(2) 子列表项
android:childDivider //各组内各子列表项之间的分隔条
android:childIndicator //显示在子列表项旁边的 Drawable 对象
设置子列表项的边界符
android:childIndicatorEnd
android:childIndicatorLeft
android:childIndicatorRight
android:childIndicatorStart
二、实例
ExpandableListView 使用很简单，UI 界面不再赘述，主要贴上 Activity 和 ExpandableListAdapter 的实现。
1. MainActivity
public class MainActivity extends AppCompatActivity {
private ArrayList<Group> gData = null;
private ArrayList<ArrayList<Item>> iData = null;
private ArrayList<Item> lData = null;
private Context mContext;
private ExpandableListView exlist_lol;
private MyBaseExpandableListAdapter myAdapter = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = MainActivity.this;
exlist_lol = findViewById(R.id.exlist_lol);
//数据准备
gData = new ArrayList<Group>();
iData = new ArrayList<ArrayList<Item>>();
gData.add(new Group("A"));
gData.add(new Group("B"));
gData.add(new Group("C"));
lData = new ArrayList<Item>();
//A组
lData.add(new Item(R.mipmap.iv_lol_icon3,"小李"));
lData.add(new Item(R.mipmap.iv_lol_icon4,"小张"));
lData.add(new Item(R.mipmap.iv_lol_icon13,"小王"));
lData.add(new Item(R.mipmap.iv_lol_icon14,"小明"));
iData.add(lData);
//B组
lData = new ArrayList<Item>();
lData.add(new Item(R.mipmap.iv_lol_icon1, "大李"));
lData.add(new Item(R.mipmap.iv_lol_icon7, "大张"));
lData.add(new Item(R.mipmap.iv_lol_icon8, "大王"));
lData.add(new Item(R.mipmap.iv_lol_icon9, "大明"));
lData.add(new Item(R.mipmap.iv_lol_icon11, "大哥"));
iData.add(lData);
//C组
lData = new ArrayList<Item>();
lData.add(new Item(R.mipmap.iv_lol_icon2, "手机"));
lData.add(new Item(R.mipmap.iv_lol_icon5, "电话"));
lData.add(new Item(R.mipmap.iv_lol_icon6, "邮件"));
lData.add(new Item(R.mipmap.iv_lol_icon10, "QQ"));
lData.add(new Item(R.mipmap.iv_lol_icon12, "微信"));
iData.add(lData);
myAdapter = new MyBaseExpandableListAdapter(gData,iData,mContext);
exlist_lol.setAdapter(myAdapter);
//为列表设置点击事件
exlist_lol.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
Toast.makeText(mContext, "你点击了：" + iData.get(groupPosition).get(childPosition).getiName(), Toast.LENGTH_SHORT).show();
return true;
}
});
}
}
2.ExpandableListAdapter
public class MyBaseExpandableListAdapter extends BaseExpandableListAdapter {
private ArrayList<Group> gData;
private ArrayList<ArrayList<Item>> iData;
private Context mContext;
public MyBaseExpandableListAdapter(ArrayList<Group> gData,ArrayList<ArrayList<Item>> iData, Context mContext) {
this.gData = gData;
this.iData = iData;
this.mContext = mContext;
}
@Override
public int getGroupCount() {
return gData.size();
}
@Override
public int getChildrenCount(int groupPosition) {
return iData.get(groupPosition).size();
}
@Override
public Group getGroup(int groupPosition) {
return gData.get(groupPosition);
}
@Override
public Item getChild(int groupPosition, int childPosition) {
return iData.get(groupPosition).get(childPosition);
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public boolean hasStableIds() {
return false;
}
//取得用于显示给定分组的视图. 这个方法仅返回分组的视图对象
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
ViewHolderGroup groupHolder;
if(convertView == null){
convertView = LayoutInflater.from(mContext).inflate(
R.layout.item_exlist_group, parent, false);
groupHolder = new ViewHolderGroup();
groupHolder.tv_group_name = (TextView) convertView.findViewById(R.id.tv_group_name);
convertView.setTag(groupHolder);
}else{
groupHolder = (ViewHolderGroup) convertView.getTag();
}
groupHolder.tv_group_name.setText(gData.get(groupPosition).getgName());
return convertView;
}
//取得显示给定分组给定子位置的数据用的视图
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
ViewHolderItem itemHolder;
if(convertView == null){
convertView = LayoutInflater.from(mContext).inflate(
R.layout.item_exlist_item, parent, false);
itemHolder = new ViewHolderItem();
itemHolder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon);
itemHolder.tv_name = (TextView) convertView.findViewById(R.id.tv_name);
convertView.setTag(itemHolder);
}else{
itemHolder = (ViewHolderItem) convertView.getTag();
}
itemHolder.img_icon.setImageResource(iData.get(groupPosition).get(childPosition).getiId());
itemHolder.tv_name.setText(iData.get(groupPosition).get(childPosition).getiName());
return convertView;
}
//设置子列表是否可选中
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
private static class ViewHolderGroup{
private TextView tv_group_name;
}
private static class ViewHolderItem{
private ImageView img_icon;
private TextView tv_name;
}
}