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Android提高十七篇之多级树形菜单的实现

时间：2024-3-2 19:57     作者：韩俊     分类： Android

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 childs=new ArrayList();

}

复制代码
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[tr] childs = new ArrayList[tr]();

}

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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：



<linearlayout xmlns:android="http://schemas.android.com/apk/res/android&quot;

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 android:layout_height="wrap_content" android:text="三层结构"

android:layout_width="160dip" android:id="@+id/btnSuper">



<expandablelistview android:id="@+id/ExpandableListView01"

android:layout_width="fill_parent" android:layout_height="fill_parent">


复制代码
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[tr] 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 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;

    }



    };

    }

复制代码
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 childs=new ArrayList();

}



List[tr] treeNodes = new ArrayList[tr]();

Context parentContext;



public TreeViewAdapter(Context view,int myPaddingLeft)

{

parentContext=view;

this.myPaddingLeft=myPaddingLeft;

}



public List[tr] GetTreeNode()

{

return treeNodes;

}



public void UpdateTreeNode(List[tr] 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;

}

}

复制代码
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[tr] childs = new ArrayList[tr]();

}



private List superTreeNodes = new ArrayList();

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 GetTreeNode() {

return superTreeNodes;

}



public void UpdateTreeNode(List 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[tr] 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;

    }

    }

复制代码

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。

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标签: android

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