Android---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：

[java]  view plain copy print ?

1. static public class TreeNode{  
2.     Object parent;  
3.     List<Object> childs=new ArrayList<Object>();  
4. }  

三级树形菜单可以用如下，子项是二级树形菜单的结构体：

[java]  view plain copy print ?

1. static public class SuperTreeNode {  
2.     Object parent;  
3.     //二级树形菜单的结构体  
4.     List<TreeViewAdapter.TreeNode> childs = new ArrayList<TreeViewAdapter.TreeNode>();  
5. }  

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：

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1. <?xml version="1.0" encoding="utf-8"?>  
2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
3.     android:orientation="vertical" android:layout_width="fill_parent"  
4.     android:layout_height="fill_parent">  
5.     <LinearLayout android:id="@+id/LinearLayout01"  
6.         android:layout_width="wrap_content" android:layout_height="wrap_content">  
7.         <Button android:layout_height="wrap_content" android:text="两层结构"  
8.             android:layout_width="160dip" android:id="@+id/btnNormal"></Button>  
9.         <Button android:layout_height="wrap_content" android:text="三层结构"  
10.             android:layout_width="160dip" android:id="@+id/btnSuper"></Button>  
11.     </LinearLayout>  
12.     <ExpandableListView android:id="@+id/ExpandableListView01"  
13.         android:layout_width="fill_parent" android:layout_height="fill_parent"></ExpandableListView>  
14. </LinearLayout>  

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

[java]  view plain copy print ?

1. package com.testExpandableList;  
2.   
3.   
4. import java.util.List;  
5. import android.app.Activity;  
6. import android.os.Bundle;  
7. import android.util.Log;  
8. import android.view.View;  
9. import android.widget.Button;  
10. import android.widget.ExpandableListView;  
11. import android.widget.ExpandableListView.OnChildClickListener;  
12. import android.widget.Toast;  
13.   
14. public class testExpandableList extends Activity {  
15.     /** Called when the activity is first created. */  
16.     ExpandableListView expandableList;  
17.     TreeViewAdapter adapter;  
18.     SuperTreeViewAdapter superAdapter;  
19.     Button btnNormal,btnSuper;  
20.     // Sample data set.  children[i] contains the children (String[]) for groups[i].  
21.     public String[] groups = { "xxxx好友", "xxxx同学", "xxxxx女人"};  
22.     public String[][]  child= {  
23.             { "A君", "B君", "C君", "D君" },  
24.             { "同学甲", "同学乙", "同学丙"},  
25.             { "御姐", "萝莉" }  
26.     };  
27.       
28.     public String[] parent = { "xxxx好友", "xxxx同学"};  
29.     public String[][][]  child_grandson= {  
30.             {{"A君"},  
31.                 {"AA","AAA"}},  
32.             {{"B君"},  
33.                 {"BBB","BBBB","BBBBB"}},  
34.             {{"C君"},  
35.                 {"CCC","CCCC"}},  
36.             {{"D君"},  
37.                 {"DDD","DDDD","DDDDD"}},  
38.     };  
39.       
40.     @Override  
41.     public void onCreate(Bundle savedInstanceState) {  
42.         super.onCreate(savedInstanceState);  
43.         setContentView(R.layout.main);  
44.         this.setTitle("ExpandableListView练习----hellogv");  
45.         btnNormal=(Button)this.findViewById(R.id.btnNormal);  
46.         btnNormal.setOnClickListener(new ClickEvent());  
47.         btnSuper=(Button)this.findViewById(R.id.btnSuper);  
48.         btnSuper.setOnClickListener(new ClickEvent());  
49.         adapter=new TreeViewAdapter(this,TreeViewAdapter.PaddingLeft>>1);  
50.         superAdapter=new SuperTreeViewAdapter(this,stvClickEvent);  
51.         expandableList=(ExpandableListView) testExpandableList.this.findViewById(R.id.ExpandableListView01);  
52.     }  
53.       
54.     class ClickEvent implements View.OnClickListener{  
55.   
56.         @Override  
57.         public void onClick(View v) {  
58.             adapter.RemoveAll();  
59.             adapter.notifyDataSetChanged();  
60.             superAdapter.RemoveAll();  
61.             superAdapter.notifyDataSetChanged();  
62.               
63.             if(v==btnNormal)  
64.             {  
65.                 List<TreeViewAdapter.TreeNode> treeNode = adapter.GetTreeNode();  
66.                 for(int i=0;i<groups.length;i++)  
67.                 {  
68.                     TreeViewAdapter.TreeNode node=new TreeViewAdapter.TreeNode();  
69.                     node.parent=groups[i];  
70.                     for(int ii=0;ii<child[i].length;ii++)  
71.                     {  
72.                         node.childs.add(child[i][ii]);  
73.                     }  
74.                     treeNode.add(node);  
75.                 }  
76.                   
77.                 adapter.UpdateTreeNode(treeNode);       
78.                 expandableList.setAdapter(adapter);  
79.                 expandableList.setOnChildClickListener(new OnChildClickListener(){  
80.   
81.                     @Override  
82.                     public boolean onChildClick(ExpandableListView arg0, View arg1,  
83.                             int parent, int children, long arg4) {  
84.                           
85.                         String str="parent id:"+String.valueOf(parent)+",children id:"+String.valueOf(children);  
86.                         Toast.makeText(testExpandableList.this, str, 300).show();  
87.                         return false;  
88.                     }  
89.                 });  
90.             }  
91.             else if(v==btnSuper){  
92.                 List<SuperTreeViewAdapter.SuperTreeNode> superTreeNode = superAdapter.GetTreeNode();  
93.                 for(int i=0;i<parent.length;i++)//第一层  
94.                 {  
95.                     SuperTreeViewAdapter.SuperTreeNode superNode=new SuperTreeViewAdapter.SuperTreeNode();  
96.                     superNode.parent=parent[i];  
97.                       
98.                     //第二层  
99.                     for(int ii=0;ii<child_grandson.length;ii++)  
100.                     {  
101.                         TreeViewAdapter.TreeNode node=new TreeViewAdapter.TreeNode();  
102.                         node.parent=child_grandson[ii][0][0];//第二级菜单的标题  
103.                           
104.                         for(int iii=0;iii<child_grandson[ii][1].length;iii++)//第三级菜单  
105.                         {  
106.                             node.childs.add(child_grandson[ii][1][iii]);  
107.                         }  
108.                         superNode.childs.add(node);  
109.                     }  
110.                     superTreeNode.add(superNode);  
111.                       
112.                 }  
113.                 superAdapter.UpdateTreeNode(superTreeNode);  
114.                 expandableList.setAdapter(superAdapter);  
115.             }  
116.         }  
117.     }  
118.   
119.     /** 
120.      * 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 
121.      */  
122.     OnChildClickListener stvClickEvent=new OnChildClickListener(){  
123.   
124.         @Override  
125.         public boolean onChildClick(ExpandableListView parent,  
126.                 View v, int groupPosition, int childPosition,  
127.                 long id) {  
128.             String str="parent id:"+String.valueOf(groupPosition)+",children id:"+String.valueOf(childPosition);  
129.             Toast.makeText(testExpandableList.this, str, 300).show();  
130.               
131.             return false;  
132.         }  
133.           
134.     };  
135. }  

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

[java]  view plain copy print ?

1. package com.testExpandableList;  
2.   
3. import java.util.ArrayList;  
4. import java.util.List;  
5. import android.content.Context;  
6. import android.util.Log;  
7. import android.view.Gravity;  
8. import android.view.View;  
9. import android.view.ViewGroup;  
10. import android.widget.AbsListView;  
11. import android.widget.BaseExpandableListAdapter;  
12. import android.widget.TextView;  
13.   
14.   
15. public class TreeViewAdapter extends BaseExpandableListAdapter{  
16.     public static final int ItemHeight=48;//每项的高度  
17.     public static final int PaddingLeft=36;//每项的高度  
18.     private int myPaddingLeft=0;//如果是由SuperTreeView调用，则作为子项需要往右移  
19.   
20.     static public class TreeNode{  
21.         Object parent;  
22.         List<Object> childs=new ArrayList<Object>();  
23.     }  
24.       
25.     List<TreeNode> treeNodes = new ArrayList<TreeNode>();  
26.     Context parentContext;  
27.       
28.     public TreeViewAdapter(Context view,int myPaddingLeft)  
29.     {  
30.         parentContext=view;  
31.         this.myPaddingLeft=myPaddingLeft;  
32.     }  
33.       
34.     public List<TreeNode> GetTreeNode()  
35.     {  
36.         return treeNodes;  
37.     }  
38.       
39.     public void UpdateTreeNode(List<TreeNode> nodes)  
40.     {  
41.         treeNodes=nodes;  
42.     }  
43.       
44.     public void RemoveAll()  
45.     {  
46.         treeNodes.clear();  
47.     }  
48.       
49.     public Object getChild(int groupPosition, int childPosition) {  
50.         return treeNodes.get(groupPosition).childs.get(childPosition);  
51.     }  
52.   
53.     public int getChildrenCount(int groupPosition) {  
54.         return treeNodes.get(groupPosition).childs.size();  
55.     }  
56.   
57.     static public TextView getTextView(Context context) {  
58.         AbsListView.LayoutParams lp = new AbsListView.LayoutParams(  
59.                 ViewGroup.LayoutParams.FILL_PARENT, ItemHeight);  
60.   
61.         TextView textView = new TextView(context);  
62.         textView.setLayoutParams(lp);  
63.         textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);  
64.         return textView;  
65.     }  
66.   
67.     public View getChildView(int groupPosition, int childPosition,  
68.             boolean isLastChild, View convertView, ViewGroup parent) {  
69.         TextView textView = getTextView(this.parentContext);  
70.         textView.setText(getChild(groupPosition, childPosition).toString());  
71.         textView.setPadding(myPaddingLeft+PaddingLeft, 0, 0, 0);  
72.         return textView;  
73.     }  
74.   
75.     public View getGroupView(int groupPosition, boolean isExpanded,  
76.             View convertView, ViewGroup parent) {  
77.         TextView textView = getTextView(this.parentContext);  
78.         textView.setText(getGroup(groupPosition).toString());  
79.         textView.setPadding(myPaddingLeft+(PaddingLeft>>1), 0, 0, 0);  
80.         return textView;  
81.     }  
82.   
83.     public long getChildId(int groupPosition, int childPosition) {  
84.         return childPosition;  
85.     }  
86.   
87.     public Object getGroup(int groupPosition) {  
88.         return treeNodes.get(groupPosition).parent;  
89.     }  
90.   
91.     public int getGroupCount() {  
92.         return treeNodes.size();  
93.     }  
94.   
95.     public long getGroupId(int groupPosition) {  
96.         return groupPosition;  
97.     }  
98.   
99.     public boolean isChildSelectable(int groupPosition, int childPosition) {  
100.         return true;  
101.     }  
102.   
103.     public boolean hasStableIds() {  
104.         return true;  
105.     }  
106. }  

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

[java]  view plain copy print ?

1. package com.testExpandableList;  
2.   
3. import java.util.ArrayList;  
4. import java.util.List;  
5. import com.testExpandableList.TreeViewAdapter.TreeNode;  
6. import android.content.Context;  
7. import android.view.View;  
8. import android.view.ViewGroup;  
9. import android.widget.AbsListView;  
10. import android.widget.BaseExpandableListAdapter;  
11. import android.widget.ExpandableListView;  
12. import android.widget.ExpandableListView.OnChildClickListener;  
13. import android.widget.ExpandableListView.OnGroupCollapseListener;  
14. import android.widget.ExpandableListView.OnGroupExpandListener;  
15. import android.widget.TextView;  
16.   
17. public class SuperTreeViewAdapter extends BaseExpandableListAdapter {  
18.   
19.     static public class SuperTreeNode {  
20.         Object parent;  
21.         //二级树形菜单的结构体  
22.         List<TreeViewAdapter.TreeNode> childs = new ArrayList<TreeViewAdapter.TreeNode>();  
23.     }  
24.   
25.     private List<SuperTreeNode> superTreeNodes = new ArrayList<SuperTreeNode>();  
26.     private Context parentContext;  
27.     private OnChildClickListener stvClickEvent;//外部回调函数  
28.       
29.     public SuperTreeViewAdapter(Context view,OnChildClickListener stvClickEvent) {  
30.         parentContext = view;  
31.         this.stvClickEvent=stvClickEvent;  
32.     }  
33.   
34.     public List<SuperTreeNode> GetTreeNode() {  
35.         return superTreeNodes;  
36.     }  
37.   
38.     public void UpdateTreeNode(List<SuperTreeNode> node) {  
39.         superTreeNodes = node;  
40.     }  
41.       
42.     public void RemoveAll()  
43.     {  
44.         superTreeNodes.clear();  
45.     }  
46.       
47.     public Object getChild(int groupPosition, int childPosition) {  
48.         return superTreeNodes.get(groupPosition).childs.get(childPosition);  
49.     }  
50.   
51.     public int getChildrenCount(int groupPosition) {  
52.         return superTreeNodes.get(groupPosition).childs.size();  
53.     }  
54.   
55.     public ExpandableListView getExpandableListView() {  
56.         AbsListView.LayoutParams lp = new AbsListView.LayoutParams(  
57.                 ViewGroup.LayoutParams.FILL_PARENT, TreeViewAdapter.ItemHeight);  
58.         ExpandableListView superTreeView = new ExpandableListView(parentContext);  
59.         superTreeView.setLayoutParams(lp);  
60.         return superTreeView;  
61.     }  
62.   
63.     /** 
64.      * 三层树结构中的第二层是一个ExpandableListView 
65.      */   
66.     public View getChildView(int groupPosition, int childPosition,  
67.             boolean isLastChild, View convertView, ViewGroup parent) {  
68.         // 是   
69.         final ExpandableListView treeView = getExpandableListView();  
70.         final TreeViewAdapter treeViewAdapter = new TreeViewAdapter(this.parentContext,0);  
71.         List<TreeNode> tmp = treeViewAdapter.GetTreeNode();//临时变量取得TreeViewAdapter的TreeNode集合，可为空  
72.         final TreeNode treeNode=(TreeNode) getChild(groupPosition, childPosition);  
73.         tmp.add(treeNode);  
74.         treeViewAdapter.UpdateTreeNode(tmp);  
75.         treeView.setAdapter(treeViewAdapter);  
76.           
77.         //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  
78.         treeView.setOnChildClickListener(this.stvClickEvent);  
79.           
80.         /** 
81.          * 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 
82.          */  
83.         treeView.setOnGroupExpandListener(new OnGroupExpandListener() {  
84.             @Override  
85.             public void onGroupExpand(int groupPosition) {  
86.                   
87.                 AbsListView.LayoutParams lp = new AbsListView.LayoutParams(  
88.                         ViewGroup.LayoutParams.FILL_PARENT,  
89.                         (treeNode.childs.size()+1)*TreeViewAdapter.ItemHeight + 10);  
90.                 treeView.setLayoutParams(lp);  
91.             }  
92.         });  
93.           
94.         /** 
95.          * 第二级菜单回收时设置为标准Item大小 
96.          */  
97.         treeView.setOnGroupCollapseListener(new OnGroupCollapseListener() {  
98.             @Override  
99.             public void onGroupCollapse(int groupPosition) {  
100.                   
101.                 AbsListView.LayoutParams lp = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,  
102.                         TreeViewAdapter.ItemHeight);  
103.                 treeView.setLayoutParams(lp);  
104.             }  
105.         });  
106.         treeView.setPadding(TreeViewAdapter.PaddingLeft, 0, 0, 0);  
107.         return treeView;  
108.     }  
109.   
110.     /** 
111.      * 三级树结构中的首层是TextView,用于作为title 
112.      */  
113.     public View getGroupView(int groupPosition, boolean isExpanded,  
114.             View convertView, ViewGroup parent) {  
115.         TextView textView = TreeViewAdapter.getTextView(this.parentContext);  
116.         textView.setText(getGroup(groupPosition).toString());  
117.         textView.setPadding(TreeViewAdapter.PaddingLeft, 0, 0, 0);  
118.         return textView;  
119.     }  
120.   
121.     public long getChildId(int groupPosition, int childPosition) {  
122.         return childPosition;  
123.     }  
124.   
125.     public Object getGroup(int groupPosition) {  
126.         return superTreeNodes.get(groupPosition).parent;  
127.     }  
128.   
129.     public int getGroupCount() {  
130.         return superTreeNodes.size();  
131.     }  
132.   
133.     public long getGroupId(int groupPosition) {  
134.         return groupPosition;  
135.     }  
136.   
137.     public boolean isChildSelectable(int groupPosition, int childPosition) {  
138.         return true;  
139.     }  
140.   
141.     public boolean hasStableIds() {  
142.         return true;  
143.     }  
144. }  

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。