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：