Android提高十七篇之多级树形菜单的实现

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

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。