ExpandableListView（似listview中的item可展开）可展开的列表组件

ExpandableListView是ListView的子类，它在普通的ListVIew的基础上进行了扩展，它把应用中的列表项分为几组，每组又可包含多个列表项。

ExpandableListView的用法与普通的LIstVIew相似，只是ExpandableListView所显示的列表项应该由ExpandableAdapter提供

ExpandableAdapter额外支持的xml属性

android:childDivider----指定各组内各子列表项之间的分隔条（颜色。view）

android:childIndicator-----显示在子列项旁边的Drawable对象

android:groupIndicator---显示在组列表项旁边的Drawable对象

下边一个简单的demo

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.ontim.demo.MainActivity">

    <ExpandableListView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:childDivider="#ffff00"
        ></ExpandableListView>

</LinearLayout>

public class MainActivity extends AppCompatActivity{
    private int[] logs;
    private String[] armType;
    private String[][] arms;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ExpandableListView list = (ExpandableListView) findViewById(R.id.list);
        initDate();
        list.setAdapter(new MyAdapter());
        //设置是否去掉上下那个箭头
        list.setGroupIndicator(null);
        list.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
                Log.i("mengshirui","MainActivity.onChildClick.groupPosition=="+groupPosition+"childPosition=="+childPosition+"armType=="+armType[groupPosition]
                        +"arm==="+arms[groupPosition][childPosition]);
                return true;
            }
        });
    }
    private void initDate() {
        //设置view的图片及描述
        logs = new int[]{R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher};
        armType = new String []{"第一","第二","第三"};
        //设置子list数据
        arms = new String[][]{
                {"001","002","003"},
                {"004","005","006"},
                {"007","008","009"},
        };
    }
    class MyAdapter extends BaseExpandableListAdapter{
        /**
         * 条目个数
         * @return
         */
        @Override
        public int getGroupCount() {
            return armType.length;
        }
        /**
         * 子条目的个数
         * @param groupPosition
         * @return
         */
        @Override
        public int getChildrenCount(int groupPosition) {
            return arms[groupPosition].length;
        }
        /**
         * 获取指定组位置处的组数据
         * @param groupPosition
         * @return
         */
        @Override
        public Object getGroup(int groupPosition) {
            return armType[groupPosition];
        }
        /**
         *
         * @param groupPosition
         * @param childPosition
         * @return
         */
        @Override
        public Object getChild(int groupPosition, int childPosition) {
            return arms[groupPosition][childPosition];
        }
        @Override
        public long getGroupId(int groupPosition) {
            return groupPosition;
        }
        @Override
        public long getChildId(int groupPosition, int childPosition) {
            return childPosition;
        }
        @Override
        public boolean hasStableIds() {
            return true;
        }
        /**
         * 每个组选项的外观
         * @param groupPosition
         * @param isExpanded
         * @param convertView
         * @param parent
         * @return
         */
        @Override
        public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
            LinearLayout ll = new LinearLayout(MainActivity.this);
            ll.setOrientation(LinearLayout.HORIZONTAL);
            ImageView iv=new ImageView(MainActivity.this);
            iv.setImageResource(logs[groupPosition]);
            ll.addView(iv);
            TextView tv= new TextView(MainActivity.this);
            tv.setText(getGroup(groupPosition).toString());
            ll.addView(tv);
            return ll;
        }
        /**
         * 子选项
         * @param groupPosition
         * @param childPosition
         * @param isLastChild
         * @param convertView
         * @param parent
         * @return
         */
        @Override
        public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
            TextView tv= new TextView(MainActivity.this);
            tv.setText(getChild(groupPosition, childPosition).toString());
            return tv;
        }
        @Override
        public boolean isChildSelectable(int groupPosition, int childPosition) {
            return true;
        }
    }
}