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：

 staticpublicclassTreeNode{
 Objectparent;
 List<Object>childs=newArrayList<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：

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

 <?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>

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

 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;
 }

 };
 }

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

 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;
 }
 }

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

 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;
 }
 }

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。