ExpandableListView 二级列表

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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:

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<?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>