027 Android 可扩展的listview:ExpandableListView的使用案例

1.ExpandableListView简介

ExpandableListView是一种用于垂直滚动展示两级列表的视图，和 ListView 的不同之处就是它可以展示两级列表，分组可以单独展开显示子选项。这些选项的数据是通过 ExpandableListAdapter 关联的。

2.xml页面布局

(1)主界面布局(CommonNumberQueryActivity对应布局)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".CommonNumberQueryActivity">

    <TextView
        style="@style/TitleStyle"
        android:text="常用号码查询" />

    <!--可以扩展的listview：ExpandableListView-->
    <ExpandableListView
        android:id="@+id/elv_common_number"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    </ExpandableListView>
</LinearLayout>

(2)elv_child_item_group.xml

<?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"
    android:padding="5dp"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/tv_group_name"
        android:text="分组名称"
        android:layout_marginLeft="40dp"
        android:textSize="16sp"
        android:textColor="@color/red"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>


</LinearLayout>

(3)elv_child_item_child.xml

<?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"
    android:padding="5dp"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/tv_name"
        android:text="电话名称"
        android:textSize="16sp"
        android:textColor="#000"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    <TextView
        android:id="@+id/tv_number"
        android:text="电话号码"
        android:textSize="16sp"
        android:textColor="#000"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

3.java后台代码

package com.example.administrator.test62360safeguard;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;

import com.example.administrator.test62360safeguard.engine.CommonNumberDao;

import java.util.List;

public class CommonNumberQueryActivity extends AppCompatActivity {

    ExpandableListView elv_common_number;
    List<CommonNumberDao.Group> groupList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_common_number_query);
        initUI();
        initData();
    }

    /**
     * 给可扩展的listview:ExpandableListView准备数据，并填充
     * 首先将对应的数据库文件放入assets目录下
     */
    private void initData() {
        CommonNumberDao commonNumberDao=new CommonNumberDao();
        //获取数据库中的数据
        groupList = commonNumberDao.getGroup();
        System.out.println("groupList:"+groupList);
        //给ExpandableListView设置数据适配器
        elv_common_number.setAdapter(new MyAdapter());
    }

    private void initUI() {
        elv_common_number = findViewById(R.id.elv_common_number);
    }

    private class MyAdapter extends BaseExpandableListAdapter {
        @Override
        public int getGroupCount() {
            return groupList.size();
        }

        @Override
        public int getChildrenCount(int groupPosition) {
            return groupList.get(groupPosition).childList.size();
        }

        @Override
        public CommonNumberDao.Group getGroup(int groupPosition) {
            return groupList.get(groupPosition);
        }

        @Override
        public CommonNumberDao.Child getChild(int groupPosition, int childPosition) {
            return groupList.get(groupPosition).childList.get(childPosition);
        }

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

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

        /**
         * 固定写法不需要修改
         */
        @Override
        public boolean hasStableIds() {
            return false;
        }

        @Override
        public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
            View view = View.inflate(getApplicationContext(), R.layout.elv_child_item_group, null);
            TextView tv_group_name = view.findViewById(R.id.tv_group_name);
            tv_group_name.setText(getGroup(groupPosition).name);
            return view;
        }

        @Override
        public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
            View view = View.inflate(getApplicationContext(), R.layout.elv_child_item_child, null);
            TextView tv_name = view.findViewById(R.id.tv_name);
            TextView tv_number = view.findViewById(R.id.tv_number);
            tv_name.setText(getChild(groupPosition, childPosition).name);
            tv_number.setText(getChild(groupPosition, childPosition).number);
            return view;
        }

        /**
         * @return 孩子节点是否响应事件
         */
        @Override
        public boolean isChildSelectable(int groupPosition, int childPosition) {
            return false;
        }
    }
}

4.效果图