Android中的二级列表的应用

看看今天实现的 Android中个多级列表的功能，其实这就是一个小组件，但是如果用好了，可以实现很大的功能呢！接着，有点累，什么都不说了，看看看实现的过程就可以了，挺简单的！

1.看看布局文件main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/bg"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="那些上过与即将被上的大学课程:"
android:textColor="#FF6100"
android:textSize="20dp"
/>
<ExpandableListView
android:id="@+id/elistview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
/>
LinearLayout>

2.接着看看主活动mainActivity.java

package com.wang;
import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.Toast;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
public class MaintActivity extends Activity {
// 创建一个上下文菜单的方法
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
// 一个垂直滚动的两级列表。取得菜单项
ExpandableListView.ExpandableListContextMenuInfo info = (ExpandableListView.ExpandableListContextMenuInfo) menuInfo;
// 获得这个类型的位置
int type = ExpandableListView
.getPackedPositionType(info.packedPosition);
// 取得所在组的索引
int group = ExpandableListView
.getPackedPositionGroup(info.packedPosition);
// 取得子菜单的索引
int child = ExpandableListView
.getPackedPositionGroup(info.packedPosition);
Toast.makeText(MaintActivity.this,
"类型 =" + type + " 分组：" + group + " 子选项：" + child,
Toast.LENGTH_LONG).show();
}
private ExpandableListView eListView = null;
private ExpandableListAdapter adapter = null;
@Override
public void onCreate(Bundle savedInstanceState) {
// 去除标题,
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
// 取消状态栏，充满全屏
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
super.setContentView(R.layout.main);
// 实例化组件
this.eListView = (ExpandableListView) findViewById(R.id.elistview);
// 声明一个adapter对象
adapter = new myExpendableadapler(this);
// 设置适配器提供了数据
this.eListView.setAdapter(this.adapter);
// 　注册一个上下文菜单显示给定的视图(多个视图可以显示上下文菜单)。
super.registerForContextMenu(this.eListView);
// 设置点击时候触发的事件 1，子选项点击事件 2。父选项单击事件 3.分组打开事件 4.分组关闭事件
this.eListView.setOnChildClickListener(new ChildClickListener());
this.eListView.setOnGroupClickListener(new GroupClickListener());
this.eListView.setOnGroupExpandListener(new GroupExpandListener());
this.eListView.setOnGroupCollapseListener(new GroupCollapseListener());
}
// /1，子选项点击事件
private class ChildClickListener implements OnChildClickListener {
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
Toast
.makeText(
MaintActivity.this,
"子选项被选中,所的组：" + groupPosition + " 子选项的位置："
+ childPosition, Toast.LENGTH_LONG).show();
return false;
}
}
// 2。父选项单击事件
private class GroupClickListener implements OnGroupClickListener {
public boolean onGroupClick(ExpandableListView parent, View v,
int groupPosition, long id) {
Toast.makeText(MaintActivity.this, "分组选项被选中,所在组： " + groupPosition,
Toast.LENGTH_LONG).show();
return false;
}
}
// 3.分组打开事件
private class GroupExpandListener implements OnGroupExpandListener {
public void onGroupExpand(int groupPosition) {
// TODO Auto-generated method stub
Toast.makeText(MaintActivity.this, "打开分组,所在组：" + groupPosition,
Toast.LENGTH_LONG).show();
}
}
// 4.分组关闭事件
private class GroupCollapseListener implements OnGroupCollapseListener {
public void onGroupCollapse(int groupPosition) {
Toast.makeText(MaintActivity.this, "关闭分组,所在组：" + groupPosition,
Toast.LENGTH_LONG).show();
}
}
}

3.主活动的实现需要一个适配器，myExpendableadapler.java

package com.wang;
import android.content.Context;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
public class myExpendableadapler extends BaseExpandableListAdapter {
// 组名称
private String[] group = new String[] { "专业课", "公共课", "选修课", "选逃课" };
// 子选项的名字
private String[][] child = new String[][] {
{ "C语言", "java程序设计基础教程", "数据库原理与应用", "数据结构", "linux下的嵌入式C语言编程",
"linux桌面应用程序设计", "计算机操作系统", "计算机组成原理" },
{ "大学英语", "马克思哲学原理", "形势与政策", "ARM体系结构", "嵌入式软件开发", "软件工程" },
{ "音乐鉴赏", "市场营销", "android开发与应用", "Visual C++实用教程", "算法分析与程序设计" },
{ "马克思哲学原理", "形势与政策" } };
private Context context = null;
// 构造函数
public myExpendableadapler(Context context) {
this.context = context;
}
public Object getChild(int groupPosition, int childPosition) {
return this.child[groupPosition][childPosition];
}
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
private TextView buildTextView() {
//LayoutParams AbsListView扩展提供一个位置来保存视图类型。
AbsListView.LayoutParams params = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT, 40);
TextView textView = new TextView(this.context);
textView.setLayoutParams(params);
//大小
textView.setTextSize(15.0f);
textView.setGravity(Gravity.LEFT+3);
textView.setPadding(40, 8, 3, 3);
return textView;
}
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
TextView textView = new TextView(this.context);
//得到每组的子选项并转换成字符串
textView.setText(this.getChild(groupPosition, childPosition).toString());
return textView;
}
//统计子选项的个数
public int getChildrenCount(int groupPosition) {
// TODO Auto-generated method stub
return this.child[groupPosition].length;
}
//得到复选项的位置
public Object getGroup(int groupPosition) {
// TODO Auto-generated method stub
return this.group[groupPosition];
}
//得到复选项的个数
public int getGroupCount() {
// TODO Auto-generated method stub
return this.group.length;
}
//得到复选项的id
public long getGroupId(int groupPosition) {
// TODO Auto-generated method stub
return groupPosition;
}
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
TextView textView = this.buildTextView();
textView.setText(this.getGroup(groupPosition).toString());
return textView;
}
//是否子选项和父选项id是稳定在改变底层数据。
public boolean hasStableIds() {
// TODO Auto-generated method stub
return true;
}
//p判断子选项是否可以选择
public boolean isChildSelectable(int groupPosition, int childPosition) {
// TODO Auto-generated method stub
return true;
}
}

4.接着就可以看看实现的效果了：

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