ExpandableListView 二级列表

先看效果：

代码：

MainActivity:

package com.example.administrator.expland;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseExpandableListAdapter;import android.widget.ExpandableListView;import android.widget.TextView;public class MainActivity extends AppCompatActivity {    private ExpandableListView expandListview;    private String[] groups = {"A", "B", "C", "D", "E"};    //注意，字符数组不要写成{{"A1,A2,A3,A4"}, {"B1,B2,B3,B4，B5"}, {"C1,C2,C3,C4"}}*/    private String[][] childs = {{"A1", "A2", "A3", "A4"}, {"A1", "A2", "A3", "B4"}, {"A1", "A2", "A3", "C4"}, {"A1", "A2", "A3", "C4"}, {"A1", "A2", "A3", "C4"}};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        expandListview = (ExpandableListView) findViewById(R.id.expandListview);        expandListview.setAdapter(new MyExpandableListView());    }    //为ExpandableListView自定义适配器    class MyExpandableListView extends BaseExpandableListAdapter {        //返回一级列表的个数        @Override        public int getGroupCount() {            return groups.length;        }        //返回每个二级列表的个数        @Override        public int getChildrenCount(int groupPosition) { //参数groupPosition表示第几个一级列表            return childs[groupPosition].length;        }        //返回一级列表的单个item（返回的是对象）        @Override        public Object getGroup(int groupPosition) {            return groups[groupPosition];        }        @Override        public Object getChild(int groupPosition, int childPosition) {            return childs[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;        }        @Override        public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {            GroupViewHolder groupViewHolder;            if (convertView == null) {                convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.item_group, parent, false);                groupViewHolder = new GroupViewHolder();                groupViewHolder.tvTitle = (TextView) convertView.findViewById(R.id.tv_group);                convertView.setTag(groupViewHolder);            } else {                groupViewHolder = (GroupViewHolder) convertView.getTag();            }            groupViewHolder.tvTitle.setText(groups[groupPosition]);            return convertView;        }        @Override        public View getChildView(int groupPosition, int childPosition, boolean b, View convertView, ViewGroup parent) {            ChildViewHolder childViewHolder;            if (convertView == null) {                convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.item_child, parent, false);                childViewHolder = new ChildViewHolder();                childViewHolder.tvTitle = (TextView) convertView.findViewById(R.id.tv_child);                convertView.setTag(childViewHolder);            } else {                childViewHolder = (ChildViewHolder) convertView.getTag();            }            childViewHolder.tvTitle.setText(childs[groupPosition][childPosition]);            return convertView;        }        @Override        public boolean isChildSelectable(int i, int i1) {            return true;        }    }    static class GroupViewHolder {        TextView tvTitle;    }    static class ChildViewHolder {        TextView tvTitle;    }}

布局：

1.activity_main:

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.administrator.expland.MainActivity">    <ExpandableListView        android:id="@+id/expandListview"        android:layout_width="690px"        android:layout_height="544px"></ExpandableListView></android.support.constraint.ConstraintLayout>

2.item_group:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <TextView        android:id="@+id/tv_group"        android:layout_width="wrap_content"        android:layout_height="30dp"        android:gravity="center"        android:text="group text"        android:layout_marginLeft="50dp"        /></LinearLayout>

3.item_child:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <ImageView        android:id="@+id/iv_child"        android:layout_width="30dp"        android:layout_height="30dp"        android:layout_marginLeft="50dp"        android:src="@mipmap/ic_launcher" />    <TextView        android:id="@+id/tv_child"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="item text" /></LinearLayout>