Android入门教程(三十四)------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：

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staticpublicclassTreeNode{
Objectparent;
List<Object>childs=newArrayList<Object>();
}

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：

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staticpublicclassSuperTreeNode{
Objectparent;
//二级树形菜单的结构体
List<TreeViewAdapter.TreeNode>childs=newArrayList<TreeViewAdapter.TreeNode>();
}

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：

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<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayoutandroid:id="@+id/LinearLayout01"
android:layout_width="wrap_content"android:layout_height="wrap_content">
<Buttonandroid:layout_height="wrap_content"android:text="两层结构"
android:layout_width="160dip"android:id="@+id/btnNormal"></Button>
<Buttonandroid:layout_height="wrap_content"android:text="三层结构"
android:layout_width="160dip"android:id="@+id/btnSuper"></Button>
</LinearLayout>
<ExpandableListViewandroid:id="@+id/ExpandableListView01"
android:layout_width="fill_parent"android:layout_height="fill_parent"></ExpandableListView>
</LinearLayout>

<?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：

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packagecom.testExpandableList;
importjava.util.List;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.util.Log;
importandroid.view.View;
importandroid.widget.Button;
importandroid.widget.ExpandableListView;
importandroid.widget.ExpandableListView.OnChildClickListener;
importandroid.widget.Toast;
publicclasstestExpandableListextendsActivity{
/**Calledwhentheactivityisfirstcreated.*/
ExpandableListViewexpandableList;
TreeViewAdapteradapter;
SuperTreeViewAdaptersuperAdapter;
ButtonbtnNormal,btnSuper;
//Sampledataset.children[i]containsthechildren(String[])forgroups[i].
publicString[]groups={"xxxx好友","xxxx同学","xxxxx女人"};
publicString[][]child={
{"A君","B君","C君","D君"},
{"同学甲","同学乙","同学丙"},
{"御姐","萝莉"}
};
publicString[]parent={"xxxx好友","xxxx同学"};
publicString[][][]child_grandson={
{{"A君"},
{"AA","AAA"}},
{{"B君"},
{"BBB","BBBB","BBBBB"}},
{{"C君"},
{"CCC","CCCC"}},
{{"D君"},
{"DDD","DDDD","DDDDD"}},
};
@Override
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.setTitle("ExpandableListView练习----hellogv");
btnNormal=(Button)this.findViewById(R.id.btnNormal);
btnNormal.setOnClickListener(newClickEvent());
btnSuper=(Button)this.findViewById(R.id.btnSuper);
btnSuper.setOnClickListener(newClickEvent());
adapter=newTreeViewAdapter(this,TreeViewAdapter.PaddingLeft>>1);
superAdapter=newSuperTreeViewAdapter(this,stvClickEvent);
expandableList=(ExpandableListView)testExpandableList.this.findViewById(R.id.ExpandableListView01);
}
classClickEventimplementsView.OnClickListener{
@Override
publicvoidonClick(Viewv){
adapter.RemoveAll();
adapter.notifyDataSetChanged();
superAdapter.RemoveAll();
superAdapter.notifyDataSetChanged();
if(v==btnNormal)
{
List<TreeViewAdapter.TreeNode>treeNode=adapter.GetTreeNode();
for(inti=0;i<groups.length;i++)
{
TreeViewAdapter.TreeNodenode=newTreeViewAdapter.TreeNode();
node.parent=groups[i];
for(intii=0;ii<child[i].length;ii++)
{
node.childs.add(child[i][ii]);
}
treeNode.add(node);
}
adapter.UpdateTreeNode(treeNode);
expandableList.setAdapter(adapter);
expandableList.setOnChildClickListener(newOnChildClickListener(){
@Override
publicbooleanonChildClick(ExpandableListViewarg0,Viewarg1,
intparent,intchildren,longarg4){
Stringstr="parentid:"+String.valueOf(parent)+",childrenid:"+String.valueOf(children);
Toast.makeText(testExpandableList.this,str,300).show();
returnfalse;
}
});
}
elseif(v==btnSuper){
List<SuperTreeViewAdapter.SuperTreeNode>superTreeNode=superAdapter.GetTreeNode();
for(inti=0;i<parent.length;i++)//第一层
{
SuperTreeViewAdapter.SuperTreeNodesuperNode=newSuperTreeViewAdapter.SuperTreeNode();
superNode.parent=parent[i];
//第二层
for(intii=0;ii<child_grandson.length;ii++)
{
TreeViewAdapter.TreeNodenode=newTreeViewAdapter.TreeNode();
node.parent=child_grandson[ii][0][0];//第二级菜单的标题
for(intiii=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
*/
OnChildClickListenerstvClickEvent=newOnChildClickListener(){
@Override
publicbooleanonChildClick(ExpandableListViewparent,
Viewv,intgroupPosition,intchildPosition,
longid){
Stringstr="parentid:"+String.valueOf(groupPosition)+",childrenid:"+String.valueOf(childPosition);
Toast.makeText(testExpandableList.this,str,300).show();
returnfalse;
}
};
}

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：

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packagecom.testExpandableList;
importjava.util.ArrayList;
importjava.util.List;
importandroid.content.Context;
importandroid.util.Log;
importandroid.view.Gravity;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.AbsListView;
importandroid.widget.BaseExpandableListAdapter;
importandroid.widget.TextView;
publicclassTreeViewAdapterextendsBaseExpandableListAdapter{
publicstaticfinalintItemHeight=48;//每项的高度
publicstaticfinalintPaddingLeft=36;//每项的高度
privateintmyPaddingLeft=0;//如果是由SuperTreeView调用，则作为子项需要往右移
staticpublicclassTreeNode{
Objectparent;
List<Object>childs=newArrayList<Object>();
}
List<TreeNode>treeNodes=newArrayList<TreeNode>();
ContextparentContext;
publicTreeViewAdapter(Contextview,intmyPaddingLeft)
{
parentContext=view;
this.myPaddingLeft=myPaddingLeft;
}
publicList<TreeNode>GetTreeNode()
{
returntreeNodes;
}
publicvoidUpdateTreeNode(List<TreeNode>nodes)
{
treeNodes=nodes;
}
publicvoidRemoveAll()
{
treeNodes.clear();
}
publicObjectgetChild(intgroupPosition,intchildPosition){
returntreeNodes.get(groupPosition).childs.get(childPosition);
}
publicintgetChildrenCount(intgroupPosition){
returntreeNodes.get(groupPosition).childs.size();
}
staticpublicTextViewgetTextView(Contextcontext){
AbsListView.LayoutParamslp=newAbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,ItemHeight);
TextViewtextView=newTextView(context);
textView.setLayoutParams(lp);
textView.setGravity(Gravity.CENTER_VERTICAL|Gravity.LEFT);
returntextView;
}
publicViewgetChildView(intgroupPosition,intchildPosition,
booleanisLastChild,ViewconvertView,ViewGroupparent){
TextViewtextView=getTextView(this.parentContext);
textView.setText(getChild(groupPosition,childPosition).toString());
textView.setPadding(myPaddingLeft+PaddingLeft,0,0,0);
returntextView;
}
publicViewgetGroupView(intgroupPosition,booleanisExpanded,
ViewconvertView,ViewGroupparent){
TextViewtextView=getTextView(this.parentContext);
textView.setText(getGroup(groupPosition).toString());
textView.setPadding(myPaddingLeft+(PaddingLeft>>1),0,0,0);
returntextView;
}
publiclonggetChildId(intgroupPosition,intchildPosition){
returnchildPosition;
}
publicObjectgetGroup(intgroupPosition){
returntreeNodes.get(groupPosition).parent;
}
publicintgetGroupCount(){
returntreeNodes.size();
}
publiclonggetGroupId(intgroupPosition){
returngroupPosition;
}
publicbooleanisChildSelectable(intgroupPosition,intchildPosition){
returntrue;
}
publicbooleanhasStableIds(){
returntrue;
}
}

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：

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packagecom.testExpandableList;
importjava.util.ArrayList;
importjava.util.List;
importcom.testExpandableList.TreeViewAdapter.TreeNode;
importandroid.content.Context;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.AbsListView;
importandroid.widget.BaseExpandableListAdapter;
importandroid.widget.ExpandableListView;
importandroid.widget.ExpandableListView.OnChildClickListener;
importandroid.widget.ExpandableListView.OnGroupCollapseListener;
importandroid.widget.ExpandableListView.OnGroupExpandListener;
importandroid.widget.TextView;
publicclassSuperTreeViewAdapterextendsBaseExpandableListAdapter{
staticpublicclassSuperTreeNode{
Objectparent;
//二级树形菜单的结构体
List<TreeViewAdapter.TreeNode>childs=newArrayList<TreeViewAdapter.TreeNode>();
}
privateList<SuperTreeNode>superTreeNodes=newArrayList<SuperTreeNode>();
privateContextparentContext;
privateOnChildClickListenerstvClickEvent;//外部回调函数
publicSuperTreeViewAdapter(Contextview,OnChildClickListenerstvClickEvent){
parentContext=view;
this.stvClickEvent=stvClickEvent;
}
publicList<SuperTreeNode>GetTreeNode(){
returnsuperTreeNodes;
}
publicvoidUpdateTreeNode(List<SuperTreeNode>node){
superTreeNodes=node;
}
publicvoidRemoveAll()
{
superTreeNodes.clear();
}
publicObjectgetChild(intgroupPosition,intchildPosition){
returnsuperTreeNodes.get(groupPosition).childs.get(childPosition);
}
publicintgetChildrenCount(intgroupPosition){
returnsuperTreeNodes.get(groupPosition).childs.size();
}
publicExpandableListViewgetExpandableListView(){
AbsListView.LayoutParamslp=newAbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,TreeViewAdapter.ItemHeight);
ExpandableListViewsuperTreeView=newExpandableListView(parentContext);
superTreeView.setLayoutParams(lp);
returnsuperTreeView;
}
/**
*三层树结构中的第二层是一个ExpandableListView
*/
publicViewgetChildView(intgroupPosition,intchildPosition,
booleanisLastChild,ViewconvertView,ViewGroupparent){
//是
finalExpandableListViewtreeView=getExpandableListView();
finalTreeViewAdaptertreeViewAdapter=newTreeViewAdapter(this.parentContext,0);
List<TreeNode>tmp=treeViewAdapter.GetTreeNode();//临时变量取得TreeViewAdapter的TreeNode集合，可为空
finalTreeNodetreeNode=(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(newOnGroupExpandListener(){
@Override
publicvoidonGroupExpand(intgroupPosition){
AbsListView.LayoutParamslp=newAbsListView.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(newOnGroupCollapseListener(){
@Override
publicvoidonGroupCollapse(intgroupPosition){
AbsListView.LayoutParamslp=newAbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
TreeViewAdapter.ItemHeight);
treeView.setLayoutParams(lp);
}
});
treeView.setPadding(TreeViewAdapter.PaddingLeft,0,0,0);
returntreeView;
}
/**
*三级树结构中的首层是TextView,用于作为title
*/
publicViewgetGroupView(intgroupPosition,booleanisExpanded,
ViewconvertView,ViewGroupparent){
TextViewtextView=TreeViewAdapter.getTextView(this.parentContext);
textView.setText(getGroup(groupPosition).toString());
textView.setPadding(TreeViewAdapter.PaddingLeft,0,0,0);
returntextView;
}
publiclonggetChildId(intgroupPosition,intchildPosition){
returnchildPosition;
}
publicObjectgetGroup(intgroupPosition){
returnsuperTreeNodes.get(groupPosition).parent;
}
publicintgetGroupCount(){
returnsuperTreeNodes.size();
}
publiclonggetGroupId(intgroupPosition){
returngroupPosition;
}
publicbooleanisChildSelectable(intgroupPosition,intchildPosition){
returntrue;
}
publicbooleanhasStableIds(){
returntrue;
}
}

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