2014最后一篇，记ExpandableListViewd的自定义

首先看下效果图，看着效果一步一步实现它

说先是两个布局，一个是group_item_layout.xml，是一级项的布局，一个是child_item_layout.xml，是二级项的布局

<?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="40dp"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/group_name"
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:layout_marginLeft="35dip"
        android:gravity="center_vertical" />

    <TextView
        android:id="@+id/group_count"
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:layout_marginLeft="5dip"
        android:gravity="center_vertical" />

</LinearLayout>

一级项里就只有两个TextView，一个用于显示标题，一个用于显示该一级项下有几个二级项

<?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:descendantFocusability="blocksDescendants"
    android:minHeight="40dp"
    android:orientation="horizontal">
    <!--android:descendantFocusability="blocksDescendants"如果不设置子项将不能点击-->
    <ImageButton
        android:id="@+id/img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginLeft="2dip"
        android:layout_marginRight="10dip" />

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/item_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true" />

        <TextView
            android:id="@+id/item_detail"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_marginTop="10dp" />
    </RelativeLayout>
</LinearLayout>

二级项里面有一个图片在最前面显示，然后是两个TextView，一个显示标题，一个显示描述.

然后是主布局，activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ExpandableListView
        android:id="@+id/expand_listview"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </ExpandableListView>

</RelativeLayout>

主布局里就一个ExpanableListView

编写Group和Child对应的Item实体类

package cn.edu.zafu.expand;


public class GroupItem {
    private String name;

    public GroupItem(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package cn.edu.zafu.expand;


public class ChildItem {
    private int resId;
    private String name;
    private String detail;

    public ChildItem(int resId, String name, String detail) {
        this.resId = resId;
        this.name = name;
        this.detail = detail;
    }

    public int getResId() {
        return resId;
    }

    public void setResId(int resId) {
        this.resId = resId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDetail() {
        return detail;
    }

    public void setDetail(String detail) {
        this.detail = detail;
    }
}

最重要的一步就是适配器了

package cn.edu.zafu.expand;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.List;


public class MyBaseExpandableListAdapter extends BaseExpandableListAdapter {
    private Context mContext = null;
    private LayoutInflater mInflater = null;
    private List<GroupItem> mGroup = null;
    private List<List<ChildItem>> mChild = null;

    public MyBaseExpandableListAdapter(Context context, List<GroupItem> group, List<List<ChildItem>> child) {
        mContext = context;
        mGroup = group;
        mChild = child;
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getGroupCount() {
        return mGroup.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return mChild.get(groupPosition).size();
    }

    @Override
    public List<ChildItem> getGroup(int groupPosition) {
        return mChild.get(groupPosition);
    }

    @Override
    public ChildItem getChild(int groupPosition, int childPosition) {
        return mChild.get(groupPosition).get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        View view = null;
        GroupViewHolder viewHolder = null;
        if (convertView == null) {
            view = mInflater.inflate(R.layout.group_item_layout, null);
            viewHolder = new GroupViewHolder();
            viewHolder.mGroupName = (TextView) view.findViewById(R.id.group_name);
            viewHolder.mGroupCount = (TextView) view.findViewById(R.id.group_count);
            view.setTag(viewHolder);
        } else {
            view = convertView;
            viewHolder = (GroupViewHolder) view.getTag();
        }
        viewHolder.mGroupName.setText(mGroup.get(groupPosition).getName());
        viewHolder.mGroupCount.setText("[" + mChild.get(groupPosition).size() + "]");
        return view;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        View view = null;
        ChildViewHolder viewHolder = null;
        if (convertView == null) {
            view = mInflater.inflate(R.layout.child_item_layout, null);
            viewHolder = new ChildViewHolder();
            viewHolder.mIcon = (ImageView) view.findViewById(R.id.img);
            viewHolder.mChildName = (TextView) view.findViewById(R.id.item_name);
            viewHolder.mDetail = (TextView) view.findViewById(R.id.item_detail);
            view.setTag(viewHolder);
        } else {
            view = convertView;
            viewHolder = (ChildViewHolder) view.getTag();
        }
        viewHolder.mIcon.setBackgroundResource(getChild(groupPosition, childPosition).getResId());
        viewHolder.mChildName.setText(getChild(groupPosition, childPosition).getName());
        viewHolder.mDetail.setText(getChild(groupPosition, childPosition).getDetail());
        return view;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
    private class GroupViewHolder {
        TextView mGroupName;
        TextView mGroupCount;
    }

    private class ChildViewHolder {
        ImageView mIcon;
        TextView mChildName;
        TextView mDetail;
    }
}

适配器的关键点事继承BaseExpandableListAdapter，并覆盖重写里面的抽象方法

最后是Activity的代码，具体见注释

package cn.edu.zafu.expand;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends Activity {
    private ExpandableListView mExpandableListView = null;
    private MyBaseExpandableListAdapter mAdapter = null;
    private List<GroupItem> mGroup = new ArrayList<GroupItem>();
    private List<List<ChildItem>> mChild = new ArrayList<List<ChildItem>>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initData();//初始化数据
        mExpandableListView = (ExpandableListView) findViewById(R.id.expand_listview);
        //mExpandableListView.setGroupIndicator(null);//前面的指示器设为无
        mAdapter = new MyBaseExpandableListAdapter(this, mGroup, mChild);//新建适配器
        mExpandableListView.setAdapter(mAdapter);//设置适配器
        mExpandableListView.setOnGroupClickListener(new MyOnGroupClickListener());//设置Group点击监听
        mExpandableListView.setOnChildClickListener(new MyOnChildClickListener());//设置Child点击监听
    }

    /*
    数据初始化
     */
    private void initData() {
        GroupItem groupItem = null;

        groupItem = new GroupItem("我的设备");
        mGroup.add(groupItem);
        groupItem = new GroupItem("我的好友");
        mGroup.add(groupItem);
        groupItem = new GroupItem("陌生人");
        mGroup.add(groupItem);

        List<ChildItem> child = null;
        ChildItem childItem = null;

        child = new ArrayList<ChildItem>();
        childItem = new ChildItem(R.drawable.expland_child_item, "我的电脑", "[在线]无需数据线，手机轻松传文件到电脑");
        child.add(childItem);
        childItem = new ChildItem(R.drawable.expland_child_item, "我的打印机", "将手机文件或照片发送到电脑连接的打印机");
        child.add(childItem);
        mChild.add(child);

        child = new ArrayList<ChildItem>();
        childItem = new ChildItem(R.drawable.expland_child_item, "羽人", "[在线]过去哪都不重要");
        child.add(childItem);
        childItem = new ChildItem(R.drawable.expland_child_item, "梦想逝去", "[在线]后来我眼瞎了");
        child.add(childItem);
        childItem = new ChildItem(R.drawable.expland_child_item, "啊飒飒", "[离线请留言]");
        child.add(childItem);
        mChild.add(child);

        child = new ArrayList<ChildItem>();
        childItem = new ChildItem(R.drawable.expland_child_item, "话说撒", "[在线]自行车自行车XC");
        child.add(childItem);
        childItem = new ChildItem(R.drawable.expland_child_item, "法规发生的变成", "[在线]啊实打实大学");
        child.add(childItem);
        childItem = new ChildItem(R.drawable.expland_child_item, "的感受到", "[离线请留言]");
        child.add(childItem);
        mChild.add(child);

    }

    /*
    一级事件监听
    */
    class MyOnGroupClickListener implements ExpandableListView.OnGroupClickListener {
        @Override
        public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
            int count = mAdapter.getChildrenCount(groupPosition);
            Toast.makeText(getApplicationContext(), "拥有的子类个数:" + count, Toast.LENGTH_SHORT).show();
            return false;//返回false能继续处理展开动作，如果返回了true，则二级项不能展开
        }
    }

    /*
     二级事件监听
     */
    class MyOnChildClickListener implements ExpandableListView.OnChildClickListener {
        @Override
        public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
            ChildItem item = mAdapter.getChild(groupPosition, childPosition);
            Toast.makeText(getApplicationContext(), "你点击了" + item.getName(), Toast.LENGTH_SHORT).show();
            return true;//事件被处理了返回true不能继续处理事件
        }
    }

}

整个流程下来可能二级项会出现不能点击的情况，这时候需要将二级项的布局文件里的所有Layout里增加属性，我这里只是增加了根layout，内部layout并没有增加，发现这样后也是可以点击的，于是内部layout就没有加这个属性了

android:descendantFocusability="blocksDescendants"

同时适配器里的方法isChildSelectedable要返回true

 @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }