本篇文章朋友在上海逛街的时候突然想到的...这两天就有想写几篇关于宋体效果的笔记，所以回家到之后就奋笔疾书的写出来发表了
ExpandableListView可开展的列表视图，本文我们要学习的是，如何应用这个件控，实现QQ挚友列表这样的效果。
一、先学习理论知识
public class
ExpandableListView
extends ListView
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android.widget.AdapterView<T extends android.widget.Adapter> |
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android.widget.ExpandableListView |
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ClassOverview
Aview that shows items in a vertically scrolling two-level list. This differsfrom the ListViewby allowing two levels: groups which can individually be expanded to show itschildren. The items come from the ExpandableListAdapterassociated with this view.
Expandablelists are able to show an indicator beside each item to display the item'scurrent state (the states are usually one of expanded group, collapsed group,child, or last child). Use setChildIndicator(Drawable) or setGroupIndicator(Drawable) (or the corresponding XML attributes) to set these indicators (see thedocs for each method to see additional state that each Drawable can have). Thedefault style for anExpandableListViewprovides indicators which will be shown next to Views given to the ExpandableListView.The layouts android.R.layout.simple_expandable_list_item_1 andandroid.R.layout.simple_expandable_list_item_2 (which should be used withSimpleCursorTreeAdapter) contain the preferred position information for indicators.
Thecontext menu information set by an ExpandableListViewwill be a ExpandableListView.ExpandableListContextMenuInfo object withpackedPositionbeing a packed position that can be used with getPackedPositionType(long) and the other similar methods.
Note: You cannot usethe value wrap_contentfor the android:layout_height attribute of a ExpandableListView in XML if the parent's size is also notstrictly specified (for example, if the parent were ScrollView you could notspecify wrap_content since it also can be any length. However, you can usewrap_content if the ExpandableListView parent has a specific size, such as 100pixels.
二、 实际
第一步计设面页
因为我们继承了ExpandableList，所以我们不必要另外再计设一个序程界面，如果只是继承了Activity，那就必须计设一个面页，里头放上android:id="@+id/android:list"的ExpandableListView。这里我们用到了自定义的子项目面页视图evchildview.xml
<?xml version="1.0"encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<ImageView android:layout_width="wrap_content"android:layout_height="wrap_content"android:id="@+id/imgHead"android:src="@drawable/icon" android:layout_alignParentTop="true"android:layout_alignParentLeft="true"></ImageView>
<TextView android:layout_width="wrap_content"android:text="name"android:layout_height="wrap_content"android:id="@+id/tvName" android:layout_alignBottom="@+id/imgHead"android:layout_toRightOf="@+id/imgHead" android:layout_marginLeft="16dp" android:layout_marginBottom="15dp"></TextView>
</RelativeLayout>
第二步、计设Activity ExpandableListViewTest
/**
* ExpandableListView example
*/
package com.figo.helloworld;
import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.Toast;
/**
* @author zhuzhifei
* @版权所有
*/
public class ExpandableListViewTest extends ExpandableListActivity {
private ExpandableListView expandableListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generatedmethod stub
super.onCreate(savedInstanceState);
//如果没有继承ExpandableListActivity采取法方一
//setContentView(R.layout.expandablelistviewtest);
//expandableListView=(ExpandableListView)findViewById(R.id.expandableListView1);
//expandableListView.setAdapter(expandableListAdapterTest);
//继承了ExpandableListActivity采取法方二
ExpandableListAdapterTest expandableListAdapterTest = newExpandableListAdapterTest(
ExpandableListViewTest.this);
setListAdapter(expandableListAdapterTest);
}
/**
* 点击子项时，触发点击事件
*/
@Override
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
TextView tvName = (TextView) v.findViewById(R.id.tvName);
Toast.makeText(ExpandableListViewTest.this, "name:" + tvName.getText(),
Toast.LENGTH_LONG).show();
return super.onChildClick(parent, v, groupPosition, childPosition,id);
}
/**
* 组合拢事件
*/
@Override
public void onGroupCollapse(int groupPosition) {
// TODO Auto-generatedmethod stub
super.onGroupCollapse(groupPosition);
}
/**
* 组开展事件
*/
@Override
public void onGroupExpand(int groupPosition) {
// TODO Auto-generatedmethod stub
super.onGroupExpand(groupPosition);
}
}
第三步、计设ExpandableListView的Adapter
/**
* ExpandableListView据数适配器
*/
package com.figo.helloworld;
import android.content.Context;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ImageView;
import android.widget.TextView;
/**
* @author zhuzhifei
* @版权所有
*/
public class ExpandableListAdapterTest extends BaseExpandableListAdapter {
public String[] groups = { "我的挚友", "复旦", "南大", "事同" };
public String[][] children = { { "刘备", "曹操", "孙权", "奥巴马" },
{ "复复", "旦旦", "日月", "华光" }, { "阿南", "大大" }, { "马超", "赵云", "林丹" } };
public int[][] figures = {
{ R.drawable.lb, R.drawable.cc, R.drawable.sq, R.drawable.abm },
{ R.drawable.ff, R.drawable.dd, R.drawable.ry, R.drawable.gh },
{ R.drawable.an, R.drawable.dada },
{ R.drawable.mc, R.drawable.zy, R.drawable.ld } };
Context context;
public ExpandableListAdapterTest(Context ct) {
context = ct;
}
/*
* 获得组数
*/
@Override
public int getGroupCount() {
return groups.length;
}
/*
* 获得以后组的子项
*/
@Override
public int getChildrenCount(int groupPosition) {
return children[groupPosition].length;
}
/*
* 获得以后组据数
*/
@Override
public Object getGroup(int groupPosition) {
return groups[groupPosition];
}
/*
* 获得以后子项据数
*/
@Override
public Object getChild(int groupPosition, int childPosition) {
return children[groupPosition][childPosition];
}
/*
* 获得组编号
*/
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
/*
* 获得子项编号
*/
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
/*
* 编号否是定稳
*/
@Override
public boolean hasStableIds() {
return true;
}
/*
* 获得组视图
*/
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
TextView textView = getGenericView();
textView.setText(getGroup(groupPosition).toString());
return textView;
}
/*
* 获得子视图，这里采取自定义的xml面页，含包一个图片和一个文本框
*
*/
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(context);
View layout = inflater.inflate(R.layout.evchildview, null);
TextView tvName = (TextView) layout.findViewById(R.id.tvName);
tvName.setText(getChild(groupPosition,childPosition).toString());
ImageView imgHead = (ImageView) layout.findViewById(R.id.imgHead);
imgHead.setImageResource(getFigure(groupPosition,childPosition));
return layout;
}
/*
* 子项否是可选
*/
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
/**
* 组视图，这里只显示一个单简的文本框
*
* @return
*/
public TextView getGenericView() {
AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT, 64);
TextView textView = new TextView(context);
textView.setLayoutParams(lp);
textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
textView.setPadding(36, 0, 0, 0);
return textView;
}
/**
* 获得肖像编号
* @param groupPosition
* @param childPosition
* @return
*/
public int getFigure(int groupPosition, int childPosition) {
return figures[groupPosition][childPosition];
}
}
第四步、AndroidManifest.xml注册Activity
<activity android:name=".ExpandableListViewTest"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
第五步、运行效果
合拢效果
开展效果
点击某项效果
文章结束给大家分享下程序员的一些笑话语录：
苹果与谷歌之争就是封闭收费与自由免费思想之争。（别急着把google来膜拜哦？那可是一家公司，以赚钱为目标的公司！当年我Party就是这样把广大劳动人民吸引过来的。今天的结果你们都看到了。）