ExpandableListView使用介绍

本文翻译自：http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/Expandable list view 是通过分类列表来组织数据的一种ListView。 在用户点击分组时他可以自动折叠或展开分组，如果你之前不熟悉ListView请先点击下面链了解一下ListView的基本用法 Android ListView Tutorial。下面我们开始学习ExpandableListView 如何使用。1.创建一个新的工程，并且将main activity 命名为MainActivity.java2.为了创建一个Expandable list view 视图，我们需要三个xml布局文件，第一个是main listview，第二个是ExpandableListView中的分类Iten使用的布局文件，第三个是展开后的列表的Item布局文件（ChildItem的布局文件）activity_main.xml<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical"android:background="#f4f4f4" ><ExpandableListViewandroid:id="@+id/lvExp"android:layout_height="match_parent"android:layout_width="match_parent"/></LinearLayout>3.创建第二个布局文件，作为Group Header（分类的Item）。我创建了一个叫 list_group.xml 的布局文件，如下所示list_group.xml<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="wrap_content"android:orientation="vertical"android:padding="8dp"android:background="#000000"><TextViewandroid:id="@+id/lblListHeader"android:layout_width="fill_parent"android:layout_height="wrap_content"android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"android:textSize="17dp"android:textColor="#f9f93d" /></LinearLayout>4.再创建一个布局文件，也就是展开列表时为其中的子Item提供布局的文件，我为他命名为 list_item.xml ，代码如下所示：list_item.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="55dip"android:orientation="vertical" ><TextViewandroid:id="@+id/lblListItem"android:layout_width="fill_parent"android:layout_height="wrap_content"android:textSize="17dip"android:paddingTop="5dp"android:paddingBottom="5dp"android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft" /></LinearLayout>5.我使用一个自定义的Adapter类去创建列表视图。创建一个新的类命名为ExpandableListAdapter.java 并且继承自BaseExpandableListAdapter这个类为创建ListView提供了许多基础的方法，其中getGroupView() –返回分组的Header视图getChildView() – 返回分组展开后的列表视图下面是自定义Adapter的代码：ExpandableListAdapter.javaimport java.util.HashMap;import java.util.List;import android.content.Context;import android.graphics.Typeface;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseExpandableListAdapter;import android.widget.TextView;public class ExpandableListAdapter extends BaseExpandableListAdapter {private Context _context;private List<String> _listDataHeader; // header titles// child data in format of header title, child titleprivate HashMap<String, List<String>> _listDataChild;public ExpandableListAdapter(Context context, List<String> listDataHeader,HashMap<String, List<String>> listChildData) {this._context = context;this._listDataHeader = listDataHeader;this._listDataChild = listChildData;}@Overridepublic Object getChild(int groupPosition,int childPosititon) {return this._listDataChild.get(this._listDataHeader.get(groupPosition)).get(childPosititon);}@Overridepublic long getChildId(int groupPosition,int childPosition) {return childPosition;}@Overridepublic View getChildView(int groupPosition,final int childPosition,boolean isLastChild, View convertView, ViewGroup parent) {final String childText = (String) getChild(groupPosition,childPosition);if (convertView == null) {LayoutInflater infalInflater = (LayoutInflater) this._context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);convertView = infalInflater.inflate(R.layout.list_item, null);}TextView txtListChild = (TextView) convertView.findViewById(R.id.lblListItem);txtListChild.setText(childText);return convertView;}@Overridepublic int getChildrenCount(int groupPosition) {return this._listDataChild.get(this._listDataHeader.get(groupPosition)).size();}@Overridepublic Object getGroup(int groupPosition) {return this._listDataHeader.get(groupPosition);}@Overridepublic int getGroupCount() {return this._listDataHeader.size();}@Overridepublic long getGroupId(int groupPosition) {return groupPosition;}@Overridepublic View getGroupView(int groupPosition,boolean isExpanded,View convertView, ViewGroup parent) {String headerTitle = (String) getGroup(groupPosition);if (convertView == null) {LayoutInflater infalInflater = (LayoutInflater) this._context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);convertView = infalInflater.inflate(R.layout.list_group, null);}TextView lblListHeader = (TextView) convertView.findViewById(R.id.lblListHeader);lblListHeader.setTypeface(null, Typeface.BOLD);lblListHeader.setText(headerTitle);return convertView;}@Overridepublic boolean hasStableIds() {return false;}@Overridepublic boolean isChildSelectable(int groupPosition,int childPosition) {return true;}}6.当你完成了自定义Adapter以后，打开你的 MainActivity.java做如下操作，创建List view所需要的数据，并且将他们传递到Adapter中，来构建ExpandableListView，代码如下：package info.androidhive.expandablelistview;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.ExpandableListView;import android.widget.ExpandableListView.OnChildClickListener;import android.widget.ExpandableListView.OnGroupClickListener;import android.widget.ExpandableListView.OnGroupCollapseListener;import android.widget.ExpandableListView.OnGroupExpandListener;import android.widget.Toast;public class MainActivity extends Activity {ExpandableListAdapter listAdapter;ExpandableListView expListView;List<String> listDataHeader;HashMap<String, List<String>> listDataChild;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// get the listviewexpListView = (ExpandableListView) findViewById(R.id.lvExp);// preparing list dataprepareListData();listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);// setting list adapterexpListView.setAdapter(listAdapter);}/** Preparing the list data*/private void prepareListData() {listDataHeader = new ArrayList<String>();listDataChild = new HashMap<String, List<String>>();// Adding child datalistDataHeader.add("Top 250");listDataHeader.add("Now Showing");listDataHeader.add("Coming Soon..");// Adding child dataList<String> top250 = new ArrayList<String>();top250.add("The Shawshank Redemption");top250.add("The Godfather");top250.add("The Godfather: Part II");top250.add("Pulp Fiction");top250.add("The Good, the Bad and the Ugly");top250.add("The Dark Knight");top250.add("12 Angry Men");List<String> nowShowing = new ArrayList<String>();nowShowing.add("The Conjuring");nowShowing.add("Despicable Me 2");nowShowing.add("Turbo");nowShowing.add("Grown Ups 2");nowShowing.add("Red 2");nowShowing.add("The Wolverine");List<String> comingSoon = new ArrayList<String>();comingSoon.add("2 Guns");comingSoon.add("The Smurfs 2");comingSoon.add("The Spectacular Now");comingSoon.add("The Canyons");comingSoon.add("Europa Report");listDataChild.put(listDataHeader.get(0), top250); // Header, Child datalistDataChild.put(listDataHeader.get(1), nowShowing);listDataChild.put(listDataHeader.get(2), comingSoon);}}好了，以上工作都完成后，你就可以运行一下你的代码了。下来就会看到下面的样子：ListVeiw 子 Item 点击事件监听为了监听ListView 子 Item的点击事件可以通过实现setOnChildClickListener这个接口来完成，代码如下：

expListView.setOnChildClickListener(

new

OnChildClickListener() {

@Override

public

boolean

onChildClick(ExpandableListView parent, View v,

int

groupPosition,

int

childPosition,

long

id) {

Toast.makeText(

getApplicationContext(),

listDataHeader.get(groupPosition)

+

" : "

+listDataChild.get(

listDataHeader.get(groupPosition)).get(

childPosition), Toast.LENGTH_SHORT)

.show();

return

false

;

}

});

列表展开事件监听实现setOnGroupExpandListener监听，在列表项展开时，它将被触发并执行。总结：ExpandableListView和ListView的用法差不多，它就相当于一个ListView的集合，每一个Item展开后又是一个ListView。因此他需要一个main.xml在这个里面声明ExpandableListView控件，然后需要一个ListItem（group header）来代表每个group Item ,然后需要一个xml来对展开后的子ListView的Item进行布局。