android ExpandableListView详解

Posted 2020-07-21 火龙裸先生

ExpandableListView是android中可以实现下拉list的一个控件，是一个垂直滚动的心事两个级别列表项手风琴试图，列表项是来自ExpandableListViewaAdapter，组可以单独展开。

重要方法：

 1 expandGroup (int groupPos) ;//在分组列表视图中 展开一组，
 2 setSelectedGroup (int groupPosition) ;//设置选择指定的组。
 3 
 4 setSelectedChild (int groupPosition, int childPosition, boolean shouldExpandGroup);//设置选择指定的子项。
 5 
 6 getPackedPositionGroup (long packedPosition);//返回所选择的组
 7 
 8 getPackedPositionForChild (int groupPosition, int childPosition) ;//返回所选择的子项
 9 
10 getPackedPositionType (long packedPosition);//返回所选择项的类型（Child,Group）
11 
12 isGroupExpanded (int groupPosition);//判断此组是否展开

 expandableListView.setDivider();这个是设定每个Group之间的分割线。

  expandableListView.setGroupIndicator();这个是设定每个Group之前的那个图标。

  expandableListView.collapseGroup(int group); 将第group组收起

ExpandableListAdapter

一个接口，将基础数据链接到一个ExpandableListView。 此接口的实施将提供访问Child的数据（由组分类），并实例化的Child和Group。

1.重要方法

　　　　getChildId (int groupPosition, int childPosition) 获取与在给定组给予孩子相关的数据。

　　　　getChildrenCount (int groupPosition) 返回在指定Group的Child数目。

案例：

首先定义个一个布局文件expandablelistview.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="fill_parent"
 4     android:layout_height="fill_parent"
 5     android:orientation="vertical" >
 6      <ExpandableListView 
 7         android:id ="@+id/expandableListView"   
 8         android:layout_width ="fill_parent"   
 9         android:layout_height ="wrap_content"   
10         >
11      </ExpandableListView>
12 </LinearLayout>

  1 package com.test;
  2 
  3 import java.util.ArrayList;
  4 import java.util.List;
  5 
  6 import javax.security.auth.PrivateCredentialPermission;
  7 
  8 import android.app.Activity;
  9 import android.os.Bundle;
 10 import android.view.Gravity;
 11 import android.view.View;
 12 import android.view.ViewGroup;
 13 import android.view.Window;
 14 import android.widget.AbsListView;
 15 import android.widget.BaseExpandableListAdapter;
 16 import android.widget.ExpandableListView;
 17 import android.widget.TextView;
 18 
 19 public class ExpandableListViewDemo extends Activity {
 20     /** Called when the activity is first created. */
 21     
 22     //定义两个List用来控制Group和Child中的String;
 23     
 24     private  List<String>  groupArray;//组列表
 25     private  List<List<String>> childArray;//子列表
 26     private  ExpandableListView  expandableListView_one;
 27     
 28     @Override
 29     public void onCreate(Bundle savedInstanceState) {
 30         super.onCreate(savedInstanceState);
 31 //        requestWindowFeature(Window.FEATURE_NO_TITLE);  //设置为无标题  
 32         setContentView(R.layout.expandablelistview);
 33         expandableListView_one =(ExpandableListView)findViewById(R.id.expandableListView);
 34         groupArray =new ArrayList<String>();
 35         childArray = new ArrayList<List<String>>();
 36        
 37         /*-第一季-*/
 38         initdate();
 39         expandableListView_one.setAdapter(new ExpandableListViewaAdapter(ExpandableListViewDemo.this));
 40         
 41         /*-第二季-*/
 42 //        groupArray.add("移动开发");
 43 //        List<String> arrayList = new ArrayList<String>();
 44 //        arrayList.add("Android");
 45 //        arrayList.add("ios");
 46 //        arrayList.add("Windows Phone");
 47 //        //组循环
 48 //        for(int index=0;index<groupArray.size();++index)
 49 //        {
 50 //            childArray.add(arrayList);
 51 //        }
 52 //        expandableListView_one.setAdapter(new ExpandableListViewaAdapter(ExpandableListViewDemo.this));
 53         
 54     }
 55     class ExpandableListViewaAdapter extends BaseExpandableListAdapter {
 56         Activity activity;
 57          public  ExpandableListViewaAdapter(Activity a)  
 58             {  
 59                 activity = a;  
 60             }  
 61        /*-----------------Child */
 62         @Override
 63         public Object getChild(int groupPosition, int childPosition) {
 64             // TODO Auto-generated method stub
 65             return childArray.get(groupPosition).get(childPosition);
 66         }
 67 
 68         @Override
 69         public long getChildId(int groupPosition, int childPosition) {
 70             // TODO Auto-generated method stub
 71             return childPosition;
 72         }
 73 
 74         @Override
 75         public View getChildView(int groupPosition, int childPosition,
 76                 boolean isLastChild, View convertView, ViewGroup parent) {
 77             
 78             String string =childArray.get(groupPosition).get(childPosition);
 79             
 80             return getGenericView(string);
 81         }
 82 
 83         @Override
 84         public int getChildrenCount(int groupPosition) {
 85             // TODO Auto-generated method stub
 86             return childArray.get(groupPosition).size();
 87         }
 88        /* ----------------------------Group */
 89         @Override
 90         public Object getGroup(int groupPosition) {
 91             // TODO Auto-generated method stub
 92             return getGroup(groupPosition);
 93         }
 94 
 95         @Override
 96         public int getGroupCount() {
 97             // TODO Auto-generated method stub
 98             return groupArray.size();
 99         }
100 
101         @Override
102         public long getGroupId(int groupPosition) {
103             // TODO Auto-generated method stub
104             return groupPosition;
105         }
106 
107         @Override
108         public View getGroupView(int groupPosition, boolean isExpanded,
109                 View convertView, ViewGroup parent) {
110             
111            String   string=groupArray.get(groupPosition);
112            return getGenericView(string);
113         }
114 
115         @Override
116         public boolean hasStableIds() {
117             // TODO Auto-generated method stub
118             return false;
119         }
120 
121         @Override
122         public boolean isChildSelectable(int groupPosition, int childPosition) 
123         {
124             // TODO Auto-generated method stub
125             return true;
126         }
127         
128         private TextView  getGenericView(String string ) 
129         {
130               AbsListView.LayoutParams  layoutParams =new AbsListView.LayoutParams(
131                     ViewGroup.LayoutParams.MATCH_PARENT,
132                     ViewGroup.LayoutParams.WRAP_CONTENT);
133               
134               TextView  textView =new TextView(activity);
135               textView.setLayoutParams(layoutParams);
136               
137               textView.setGravity(Gravity.CENTER_VERTICAL |Gravity.LEFT);
138               
139               textView.setPadding(40, 0, 0, 0);
140               textView.setText(string);
141               return textView;
142          }
143     }
144     
145     private void initdate() 
146     {
147         addInfo("语言", new String[]{"Oracle","Java","Linux","Jquery"});
148         addInfo("男人的需求", new String[]{"金钱","事业","权力","女人","房子","车","球"});
149     }
150     private void addInfo(String group,String []child) {
151         
152         groupArray.add(group);
153         
154         List<String>  childItem =new ArrayList<String>();
155         
156         for(int index=0;index<child.length;index++)
157         {
158             childItem.add(child[index]);
159         }
160          childArray.add(childItem);
161     }
162 }