Android提高十七篇之多级树形菜单的实现

http://blog.csdn.net/hellogv/archive/2011/01/06/6120133.aspx
在Android里要实现树形菜单，都是用ExpandableList(也有高手自己继承ListView或者LinearLayout来做)，但是ExpandableList一般只能实现2级树形菜单......本文也依然使用ExpandableList，但是要实现的是3级树形菜单。本文程序运行效果图：



当用BaseExpandableListAdapter来实现二级树形菜单时，父项(getGroupView())和子项(getChildView())都是使用TextView。当要实现三级树形菜单时，子项(getChildView())就必须使用ExpandableList了.......另外还要定义结构体来方便调用三级树形的数据，二级树形菜单可以用如下：

static public class TreeNode{  
    Object parent;  
    List<Object> childs=new ArrayList<Object>();  
}  

三级树形菜单可以用如下，子项是二级树形菜单的结构体：

static public class SuperTreeNode {  
    Object parent;  
    //二级树形菜单的结构体  
    List<TreeViewAdapter.TreeNode> childs = new ArrayList<TreeViewAdapter.TreeNode>();  
}  

实现三级树形菜单有两点要注意的：

1、第二级也是个树形菜单，因此必须在第二级项目展开/回收时设置足够的空间来完全显示二级树形菜单；

2、在实现三级树形菜单时，发现菜单的方法都是用不了(如OnChildClickListener、OnGroupClickListener等)，因此要获得选中的数据就必须在外部定义好回调函数，然后在第二级生成二级树形菜单时回调这个外部函数。

PS：本文在解决No.2关键点的时候，只能取得第三级选中的序号.....而第一，第二级依然无法获取其序号。

main.xml源码如下：

<?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">  
    <LinearLayout android:id="@+id/LinearLayout01"  
        android:layout_width="wrap_content" android:layout_height="wrap_content">  
        <Button android:layout_height="wrap_content" android:text="两层结构"  
            android:layout_width="160dip" android:id="@+id/btnNormal"></Button>  
        <Button android:layout_height="wrap_content" android:text="三层结构"  
            android:layout_width="160dip" android:id="@+id/btnSuper"></Button>  
    </LinearLayout>  
    <ExpandableListView android:id="@+id/ExpandableListView01"  
        android:layout_width="fill_parent" android:layout_height="fill_parent"></ExpandableListView>  
</LinearLayout>  

testExpandableList.java是主类，调用其他工具类，源码如下：

package com.testExpandableList;  
  
  
import java.util.List;  
import android.app.Activity;  
import android.os.Bundle;  
import android.util.Log;  
import android.view.View;  
import android.widget.Button;  
import android.widget.ExpandableListView;  
import android.widget.ExpandableListView.OnChildClickListener;  
import android.widget.Toast;  
  
public class testExpandableList extends Activity {  
    /** Called when the activity is first created. */  
    ExpandableListView expandableList;  
    TreeViewAdapter adapter;  
    SuperTreeViewAdapter superAdapter;  
    Button btnNormal,btnSuper;  
    // Sample data set.  children[i] contains the children (String[]) for groups[i].  
    public String[] groups = { "xxxx好友", "xxxx同学", "xxxxx女人"};  
    public String[][]  child= {  
            { "A君", "B君", "C君", "D君" },  
            { "同学甲", "同学乙", "同学丙"},  
            { "御姐", "萝莉" }  
    };  
      
    public String[] parent = { "xxxx好友", "xxxx同学"};  
    public String[][][]  child_grandson= {  
            {{"A君"},  
                {"AA","AAA"}},  
            {{"B君"},  
                {"BBB","BBBB","BBBBB"}},  
            {{"C君"},  
                {"CCC","CCCC"}},  
            {{"D君"},  
                {"DDD","DDDD","DDDDD"}},  
    };  
      
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        this.setTitle("ExpandableListView练习----hellogv");  
        btnNormal=(Button)this.findViewById(R.id.btnNormal);  
        btnNormal.setOnClickListener(new ClickEvent());  
        btnSuper=(Button)this.findViewById(R.id.btnSuper);  
        btnSuper.setOnClickListener(new ClickEvent());  
        adapter=new TreeViewAdapter(this,TreeViewAdapter.PaddingLeft>>1);  
        superAdapter=new SuperTreeViewAdapter(this,stvClickEvent);  
        expandableList=(ExpandableListView) testExpandableList.this.findViewById(R.id.ExpandableListView01);  
    }  
      
    class ClickEvent implements View.OnClickListener{  
  
        @Override  
        public void onClick(View v) {  
            adapter.RemoveAll();  
            adapter.notifyDataSetChanged();  
            superAdapter.RemoveAll();  
            superAdapter.notifyDataSetChanged();  
              
            if(v==btnNormal)  
            {  
                List<TreeViewAdapter.TreeNode> treeNode = adapter.GetTreeNode();  
                for(int i=0;i<groups.length;i++)  
                {  
                    TreeViewAdapter.TreeNode node=new TreeViewAdapter.TreeNode();  
                    node.parent=groups[i];  
                    for(int ii=0;ii<child[i].length;ii++)  
                    {  
                        node.childs.add(child[i][ii]);  
                    }  
                    treeNode.add(node);  
                }  
                  
                adapter.UpdateTreeNode(treeNode);       
                expandableList.setAdapter(adapter);  
                expandableList.setOnChildClickListener(new OnChildClickListener(){  
  
                    @Override  
                    public boolean onChildClick(ExpandableListView arg0, View arg1,  
                            int parent, int children, long arg4) {  
                          
                        String str="parent id:"+String.valueOf(parent)+",children id:"+String.valueOf(children);  
                        Toast.makeText(testExpandableList.this, str, 300).show();  
                        return false;  
                    }  
                });  
            }  
            else if(v==btnSuper){  
                List<SuperTreeViewAdapter.SuperTreeNode> superTreeNode = superAdapter.GetTreeNode();  
                for(int i=0;i<parent.length;i++)//第一层  
                {  
                    SuperTreeViewAdapter.SuperTreeNode superNode=new SuperTreeViewAdapter.SuperTreeNode();  
                    superNode.parent=parent[i];  
                      
                    //第二层  
                    for(int ii=0;ii<child_grandson.length;ii++)  
                    {  
                        TreeViewAdapter.TreeNode node=new TreeViewAdapter.TreeNode();  
                        node.parent=child_grandson[ii][0][0];//第二级菜单的标题  
                          
                        for(int iii=0;iii<child_grandson[ii][1].length;iii++)//第三级菜单  
                        {  
                            node.childs.add(child_grandson[ii][1][iii]);  
                        }  
                        superNode.childs.add(node);  
                    }  
                    superTreeNode.add(superNode);  
                      
                }  
                superAdapter.UpdateTreeNode(superTreeNode);  
                expandableList.setAdapter(superAdapter);  
            }  
        }  
    }  
  
    /** 
     * 三级树形菜单的事件不再可用，本函数由三级树形菜单的子项（二级菜单）进行回调 
     */  
    OnChildClickListener stvClickEvent=new OnChildClickListener(){  
  
        @Override  
        public boolean onChildClick(ExpandableListView parent,  
                View v, int groupPosition, int childPosition,  
                long id) {  
            String str="parent id:"+String.valueOf(groupPosition)+",children id:"+String.valueOf(childPosition);  
            Toast.makeText(testExpandableList.this, str, 300).show();  
              
            return false;  
        }  
          
    };  
}  

TreeViewAdapter.java是实现二级树形菜单的工具类，源码如下：

package com.testExpandableList;  
  
import java.util.ArrayList;  
import java.util.List;  
import android.content.Context;  
import android.util.Log;  
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 TreeViewAdapter extends BaseExpandableListAdapter{  
    public static final int ItemHeight=48;//每项的高度  
    public static final int PaddingLeft=36;//每项的高度  
    private int myPaddingLeft=0;//如果是由SuperTreeView调用，则作为子项需要往右移  
  
    static public class TreeNode{  
        Object parent;  
        List<Object> childs=new ArrayList<Object>();  
    }  
      
    List<TreeNode> treeNodes = new ArrayList<TreeNode>();  
    Context parentContext;  
      
    public TreeViewAdapter(Context view,int myPaddingLeft)  
    {  
        parentContext=view;  
        this.myPaddingLeft=myPaddingLeft;  
    }  
      
    public List<TreeNode> GetTreeNode()  
    {  
        return treeNodes;  
    }  
      
    public void UpdateTreeNode(List<TreeNode> nodes)  
    {  
        treeNodes=nodes;  
    }  
      
    public void RemoveAll()  
    {  
        treeNodes.clear();  
    }  
      
    public Object getChild(int groupPosition, int childPosition) {  
        return treeNodes.get(groupPosition).childs.get(childPosition);  
    }  
  
    public int getChildrenCount(int groupPosition) {  
        return treeNodes.get(groupPosition).childs.size();  
    }  
  
    static public TextView getTextView(Context context) {  
        AbsListView.LayoutParams lp = new AbsListView.LayoutParams(  
                ViewGroup.LayoutParams.FILL_PARENT, ItemHeight);  
  
        TextView textView = new TextView(context);  
        textView.setLayoutParams(lp);  
        textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);  
        return textView;  
    }  
  
    public View getChildView(int groupPosition, int childPosition,  
            boolean isLastChild, View convertView, ViewGroup parent) {  
        TextView textView = getTextView(this.parentContext);  
        textView.setText(getChild(groupPosition, childPosition).toString());  
        textView.setPadding(myPaddingLeft+PaddingLeft, 0, 0, 0);  
        return textView;  
    }  
  
    public View getGroupView(int groupPosition, boolean isExpanded,  
            View convertView, ViewGroup parent) {  
        TextView textView = getTextView(this.parentContext);  
        textView.setText(getGroup(groupPosition).toString());  
        textView.setPadding(myPaddingLeft+(PaddingLeft>>1), 0, 0, 0);  
        return textView;  
    }  
  
    public long getChildId(int groupPosition, int childPosition) {  
        return childPosition;  
    }  
  
    public Object getGroup(int groupPosition) {  
        return treeNodes.get(groupPosition).parent;  
    }  
  
    public int getGroupCount() {  
        return treeNodes.size();  
    }  
  
    public long getGroupId(int groupPosition) {  
        return groupPosition;  
    }  
  
    public boolean isChildSelectable(int groupPosition, int childPosition) {  
        return true;  
    }  
  
    public boolean hasStableIds() {  
        return true;  
    }  
}  

SuperTreeViewAdapter.java是实现三级树形菜单的工具类，会用到TreeViewAdapter.java，源码如下：

package com.testExpandableList;  
  
import java.util.ArrayList;  
import java.util.List;  
import com.testExpandableList.TreeViewAdapter.TreeNode;  
import android.content.Context;  
import android.view.View;  
import android.view.ViewGroup;  
import android.widget.AbsListView;  
import android.widget.BaseExpandableListAdapter;  
import android.widget.ExpandableListView;  
import android.widget.ExpandableListView.OnChildClickListener;  
import android.widget.ExpandableListView.OnGroupCollapseListener;  
import android.widget.ExpandableListView.OnGroupExpandListener;  
import android.widget.TextView;  
  
public class SuperTreeViewAdapter extends BaseExpandableListAdapter {  
  
    static public class SuperTreeNode {  
        Object parent;  
        //二级树形菜单的结构体  
        List<TreeViewAdapter.TreeNode> childs = new ArrayList<TreeViewAdapter.TreeNode>();  
    }  
  
    private List<SuperTreeNode> superTreeNodes = new ArrayList<SuperTreeNode>();  
    private Context parentContext;  
    private OnChildClickListener stvClickEvent;//外部回调函数  
      
    public SuperTreeViewAdapter(Context view,OnChildClickListener stvClickEvent) {  
        parentContext = view;  
        this.stvClickEvent=stvClickEvent;  
    }  
  
    public List<SuperTreeNode> GetTreeNode() {  
        return superTreeNodes;  
    }  
  
    public void UpdateTreeNode(List<SuperTreeNode> node) {  
        superTreeNodes = node;  
    }  
      
    public void RemoveAll()  
    {  
        superTreeNodes.clear();  
    }  
      
    public Object getChild(int groupPosition, int childPosition) {  
        return superTreeNodes.get(groupPosition).childs.get(childPosition);  
    }  
  
    public int getChildrenCount(int groupPosition) {  
        return superTreeNodes.get(groupPosition).childs.size();  
    }  
  
    public ExpandableListView getExpandableListView() {  
        AbsListView.LayoutParams lp = new AbsListView.LayoutParams(  
                ViewGroup.LayoutParams.FILL_PARENT, TreeViewAdapter.ItemHeight);  
        ExpandableListView superTreeView = new ExpandableListView(parentContext);  
        superTreeView.setLayoutParams(lp);  
        return superTreeView;  
    }  
  
    /** 
     * 三层树结构中的第二层是一个ExpandableListView 
     */   
    public View getChildView(int groupPosition, int childPosition,  
            boolean isLastChild, View convertView, ViewGroup parent) {  
        // 是   
        final ExpandableListView treeView = getExpandableListView();  
        final TreeViewAdapter treeViewAdapter = new TreeViewAdapter(this.parentContext,0);  
        List<TreeNode> tmp = treeViewAdapter.GetTreeNode();//临时变量取得TreeViewAdapter的TreeNode集合，可为空  
        final TreeNode treeNode=(TreeNode) getChild(groupPosition, childPosition);  
        tmp.add(treeNode);  
        treeViewAdapter.UpdateTreeNode(tmp);  
        treeView.setAdapter(treeViewAdapter);  
          
        //关键点：取得选中的二级树形菜单的父子节点,结果返回给外部回调函数  
        treeView.setOnChildClickListener(this.stvClickEvent);  
          
        /** 
         * 关键点：第二级菜单展开时通过取得节点数来设置第三级菜单的大小 
         */  
        treeView.setOnGroupExpandListener(new OnGroupExpandListener() {  
            @Override  
            public void onGroupExpand(int groupPosition) {  
                  
                AbsListView.LayoutParams lp = new AbsListView.LayoutParams(  
                        ViewGroup.LayoutParams.FILL_PARENT,  
                        (treeNode.childs.size()+1)*TreeViewAdapter.ItemHeight + 10);  
                treeView.setLayoutParams(lp);  
            }  
        });  
          
        /** 
         * 第二级菜单回收时设置为标准Item大小 
         */  
        treeView.setOnGroupCollapseListener(new OnGroupCollapseListener() {  
            @Override  
            public void onGroupCollapse(int groupPosition) {  
                  
                AbsListView.LayoutParams lp = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,  
                        TreeViewAdapter.ItemHeight);  
                treeView.setLayoutParams(lp);  
            }  
        });  
        treeView.setPadding(TreeViewAdapter.PaddingLeft, 0, 0, 0);  
        return treeView;  
    }  
  
    /** 
     * 三级树结构中的首层是TextView,用于作为title 
     */  
    public View getGroupView(int groupPosition, boolean isExpanded,  
            View convertView, ViewGroup parent) {  
        TextView textView = TreeViewAdapter.getTextView(this.parentContext);  
        textView.setText(getGroup(groupPosition).toString());  
        textView.setPadding(TreeViewAdapter.PaddingLeft, 0, 0, 0);  
        return textView;  
    }  
  
    public long getChildId(int groupPosition, int childPosition) {  
        return childPosition;  
    }  
  
    public Object getGroup(int groupPosition) {  
        return superTreeNodes.get(groupPosition).parent;  
    }  
  
    public int getGroupCount() {  
        return superTreeNodes.size();  
    }  
  
    public long getGroupId(int groupPosition) {  
        return groupPosition;  
    }  
  
    public boolean isChildSelectable(int groupPosition, int childPosition) {  
        return true;  
    }  
  
    public boolean hasStableIds() {  
        return true;  
    }  
}  

总结，使用ExpandableList实现三级树形菜单时有些bug不好解决，而且定义三维数组的时候也要倍加小心......所以尽量把数据化简来使用二级树形菜单。