• 【Android】扩展BaseExpandableListAdpter实现ExpandableAdapter

    今天分享如何扩展BaseExpandableListAdpter实现ExpandableAdapter，很简单的一个例子。

    效果示例：

     

    核心是重写BaseExpandableListAdpter，其中BaseExpandableListAdpter则分成了两部分：组和子列表，要注意的是，重写isChildSelectable()方法需要返回true，不然不会触发 子Item的点击事件！

    XML代码分享

    主xml文件

    1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    2.     xmlns:tools="http://schemas.android.com/tools"
    3.     android:layout_width="match_parent"
    4.     android:layout_height="match_parent"
    5.     android:padding="5dp"
    6.     tools:context=".MainActivity">
    7.  
    8.     <ExpandableListView
    9.         android:id="@+id/exlist_lol"
    10.         android:layout_width="match_parent"
    11.         android:layout_height="match_parent"
    12.         android:childDivider="#E02D2F" />
    13.  
    14. RelativeLayout>

    父xml文件

    1. "1.0" encoding="utf-8"?>
    2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    3.     android:layout_width="match_parent"
    4.     android:layout_height="match_parent"
    5.     android:orientation="horizontal"
    6.     android:padding="5dp">
    7.  
    8.     <TextView
    9.         android:id="@+id/tv_group_name"
    10.         android:layout_width="match_parent"
    11.         android:layout_height="56dp"
    12.         android:gravity="center_vertical"
    13.         android:paddingLeft="30dp"
    14.         android:text="Parent"
    15.         android:textStyle="bold"
    16.         android:textSize="20sp" />
    17.  
    18. LinearLayout>

    子xml文件

    1. "1.0" encoding="utf-8"?>
    2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    3.     android:layout_width="match_parent"
    4.     android:layout_height="match_parent"
    5.     android:orientation="horizontal"
    6.     android:padding="5dp">
    7.  
    8.     <TextView
    9.         android:id="@+id/tv_name"
    10.         android:layout_width="wrap_content"
    11.         android:layout_height="wrap_content"
    12.         android:layout_marginLeft="15dp"
    13.         android:layout_marginTop="15dp"
    14.         android:focusable="false"
    15.         android:text="child"
    16.         android:textSize="18sp" />
    17.  
    18.     <ImageView
    19.         android:id="@+id/img_icon"
    20.         android:layout_width="38dp"
    21.         android:layout_height="47dp"
    22.         android:layout_alignParentRight="true"
    23.         android:layout_centerInParent="true"
    24.         android:paddingRight="10dp"
    25.         android:src="@drawable/arr_right" />
    26. LinearLayout>

    Activity代码分享

    1. import android.content.Context;
    2. import android.content.res.Resources;
    3. import android.os.Bundle;
    4. import android.view.View;
    5. import android.widget.ExpandableListView;
    6. import android.widget.Toast;
    7.  
    8. import androidx.appcompat.app.AppCompatActivity;
    9.  
    10. import java.util.ArrayList;
    11.  
    12. public class MainActivity extends AppCompatActivity {
    13.  
    14.     private ArrayList gData = null;
    15.     private ArrayList> iData = null;
    16.     private ArrayList lData = null;
    17.     private Context mContext;
    18.     private ExpandableListView exlist_lol;
    19.     private MyBaseExpandableListAdapter myAdapter = null;
    20.  
    21.  
    22.     @Override
    23.     protected void onCreate(Bundle savedInstanceState) {
    24.         super.onCreate(savedInstanceState);
    25.         setContentView(R.layout.activity_main);
    26.         mContext = MainActivity.this;
    27.         exlist_lol = (ExpandableListView) findViewById(R.id.exlist_lol);
    28.  
    29.  
    30.         //数据准备
    31.         gData = new ArrayList();
    32.         iData = new ArrayList>();
    33.         gData.add(new Group("Subject"));
    34.  
    35.         lData = new ArrayList();
    36.  
    37.         Resources res =getResources();
    38.         String[] subject=res.getStringArray(R.array.subject);
    39.  
    40.         for(int i=0;i
    41.         {
    42.             lData.add(new Item(R.drawable.arr_right,subject[i]));  //值得说明的是，这里的数据源于项目中的values/list.xml，同理，一级目录也可以用这样的方式赋值
    43.         }
    44.         iData.add(lData);
    45.  
    46.  
    47.         myAdapter = new MyBaseExpandableListAdapter(gData,iData,mContext);
    48.         exlist_lol.setAdapter(myAdapter);
    49.  
    50.  
    51.         //为列表设置点击事件
    52.         exlist_lol.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
    53.             @Override
    54.             public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
    55.                 Toast.makeText(mContext, "你点击了：" + iData.get(groupPosition).get(childPosition).getiName(), Toast.LENGTH_SHORT).show();
    56.                 return true;
    57.             }
    58.         });
    59.  
    60.  
    61.     }
    62. }

    values下的list.xml（Tip:像一般的下拉框Spinner也可以读取xml资源）

    1. "1.0" encoding="utf-8"?>
    2. <resources>
    3. 　　    <string-array name="subject">
    4. 　　        <item>Chineseitem>
    5. 　　        <item>Mathitem>
    6. 　　        <item>Englishitem>
    7. 　　        <item>Physicsitem>
    8. 　　        <item>Chemistryitem>
    9.            <item>Historyitem>
    10. 　　    string-array>
    11. resources>

    Adapter代码分享

    1. package com.example.listmain;
    2.  
    3. import android.content.Context;
    4. import android.view.LayoutInflater;
    5. import android.view.View;
    6. import android.view.ViewGroup;
    7. import android.widget.BaseExpandableListAdapter;
    8. import android.widget.ImageView;
    9. import android.widget.TextView;
    10.  
    11. import java.util.ArrayList;
    12.  
    13. public class MyBaseExpandableListAdapter extends BaseExpandableListAdapter {
    14.  
    15.     private ArrayList gData;
    16.     private ArrayList> iData;
    17.     private Context mContext;
    18.  
    19.     public MyBaseExpandableListAdapter(ArrayList gData, ArrayList> iData, Context mContext) {
    20.         this.gData = gData;
    21.         this.iData = iData;
    22.         this.mContext = mContext;
    23.     }
    24.  
    25.     @Override
    26.     public int getGroupCount() {
    27.         return gData.size();
    28.     }
    29.  
    30.     @Override
    31.     public int getChildrenCount(int groupPosition) {
    32.         return iData.get(groupPosition).size();
    33.     }
    34.  
    35.     @Override
    36.     public Group getGroup(int groupPosition) {
    37.         return gData.get(groupPosition);
    38.     }
    39.  
    40.     @Override
    41.     public Item getChild(int groupPosition, int childPosition) {
    42.         return iData.get(groupPosition).get(childPosition);
    43.     }
    44.  
    45.     @Override
    46.     public long getGroupId(int groupPosition) {
    47.         return groupPosition;
    48.     }
    49.  
    50.     @Override
    51.     public long getChildId(int groupPosition, int childPosition) {
    52.         return childPosition;
    53.     }
    54.  
    55.     @Override
    56.     public boolean hasStableIds() {
    57.         return true;
    58.     }
    59.  
    60.     //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
    61.     @Override
    62.     public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
    63.  
    64.         ViewHolderGroup groupHolder;
    65.         if(convertView == null){
    66.             convertView = LayoutInflater.from(mContext).inflate(
    67.                     R.layout.item_exlist_group, parent, false);
    68.             groupHolder = new ViewHolderGroup();
    69.             groupHolder.tv_group_name = (TextView) convertView.findViewById(R.id.tv_group_name);
    70.             convertView.setTag(groupHolder);
    71.         }else{
    72.             groupHolder = (ViewHolderGroup) convertView.getTag();
    73.         }
    74.         groupHolder.tv_group_name.setText(gData.get(groupPosition).getgName());
    75.         return convertView;
    76.     }
    77.  
    78.     //取得显示给定分组给定子位置的数据用的视图
    79.     @Override
    80.     public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
    81.         ViewHolderItem itemHolder;
    82.         if(convertView == null){
    83.             convertView = LayoutInflater.from(mContext).inflate(
    84.                     R.layout.item_exlist_item, parent, false);
    85.             itemHolder = new ViewHolderItem();
    86.             itemHolder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon);
    87.             itemHolder.tv_name = (TextView) convertView.findViewById(R.id.tv_name);
    88.             convertView.setTag(itemHolder);
    89.         }else{
    90.             itemHolder = (ViewHolderItem) convertView.getTag();
    91.         }
    92.         itemHolder.img_icon.setImageResource(iData.get(groupPosition).get(childPosition).getiId());
    93.         itemHolder.tv_name.setText(iData.get(groupPosition).get(childPosition).getiName());
    94.         return convertView;
    95.     }
    96.  
    97.     //设置子列表是否可选中
    98.     @Override
    99.     public boolean isChildSelectable(int groupPosition, int childPosition) {
    100.         return true;
    101.     }
    102.  
    103.  
    104.     private static class ViewHolderGroup{
    105.         private TextView tv_group_name;
    106.     }
    107.  
    108.     private static class ViewHolderItem{
    109.         private ImageView img_icon;
    110.         private TextView tv_name;
    111.     }
    112.  
    113. }

    还有两个类：Item 和 Group

    1.  
    2. public class Item {
    3.  
    4.     private int iId;
    5.     private String iName;
    6.  
    7.     public Item() {
    8.     }
    9.  
    10.     public Item(int iId, String iName) {
    11.         this.iId = iId;
    12.         this.iName = iName;
    13.     }
    14.  
    15.     public int getiId() {
    16.         return iId;
    17.     }
    18.  
    19.     public String getiName() {
    20.         return iName;
    21.     }
    22.  
    23.     public void setiId(int iId) {
    24.         this.iId = iId;
    25.     }
    26.  
    27.     public void setiName(String iName) {
    28.         this.iName = iName;
    29.     }
    30. }
    1. public class Group {
    2.     private String gName;
    3.  
    4.     public Group() {
    5.     }
    6.  
    7.     public Group(String gName) {
    8.         this.gName = gName;
    9.     }
    10.  
    11.     public String getgName() {
    12.         return gName;
    13.     }
    14.  
    15.     public void setgName(String gName) {
    16.         this.gName = gName;
    17.     }
    18. }

    补充一下，网上说实现ExpandableAdapter有三种方式：

    1. 扩展BaseExpandableListAdpter实现ExpandableAdapter。

    2. 使用SimpleExpandableListAdpater将两个List集合包装成ExpandableAdapter

    3. 使用simpleCursorTreeAdapter将Cursor中的数据包装成SimpleCuroTreeAdapter 

    鉴于我写的Demo比较简单，所以就先用了第一种。后面有时间我也会另外研究一下~

    最后，本次练手的代码可以左转到我的主页查看下载资源，欢迎一起交流学习吖~

    参考资料：

    ExpandableListView使用方法详解_会飞的鱼儿android的博客-CSDN博客_expandablelistview

    2.5.5 ExpandableListView(可折叠列表)的基本使用 | 菜鸟教程

  • 相关阅读:
    python3.9运行出现编码问题，在其他电脑上可以正常运行
    【MySQL】使用C/C++访问MySQL
    【HarmonyOS】【JAVA UI】自定义通知的实现
    极简7照训练法，奇趣相机引领儿童AI摄影潮流
    C51 - 定时器
    DP27 跳跃游戏(二)
    CSS中clip-path、white-space使用
    【开源】SpringBoot框架开发音乐平台
    高手过招不用鼠标，一款超好用的跨平台命令行界面库
    JavaScript-箭头函数
  • 原文地址：https://blog.csdn.net/sinat_28782331/article/details/124964920