多級樹形菜單的實現

本文來自http://blog.csdn.net/hellogv/
，引用必須註明出處！

在Android裡要實現樹形菜單，都是用ExpandableList(也有高手自己繼承ListView或者LinearLayout來做)，但是ExpandableList一般只能實現2級樹形菜單......本文也依然使用ExpandableList，但是要實現的是3級樹形菜單。本文程式運行：

當用BaseExpandableListAdapter來實現二級樹形菜單時，父項(getGroupView())和子項(getChildView())都是使用TextView。當要實現三級樹形菜單時，子項(getChildView())就必須使用ExpandableList了.......另外還要定義結構體來方便調用三級樹形的資料，二級樹形菜單可以用如下：

static public class TreeNode{<br />Object parent;<br />List<Object> childs=new ArrayList<Object>();<br />}

三級樹形菜單可以用如下，子項是二級樹形菜單的結構體：

static public class SuperTreeNode {<br />Object parent;<br />//二級樹形菜單的結構體<br />List<TreeViewAdapter.TreeNode> childs = new ArrayList<TreeViewAdapter.TreeNode>();<br />}

實現三級樹形菜單有兩點要注意的：

1、第二級也是個樹形菜單，因此必須在第二級項目展開/回收時設定足夠的空間來完全顯示二級樹形菜單；

2、在實現三級樹形菜單時，發現菜單的方法都是用不了(如OnChildClickListener、OnGroupClickListener等)，因此要獲得選中的資料就必須在外部定義好回呼函數，然後在第二級產生二級樹形菜單時回調這個外部函數。

PS：本文在解決No.2關鍵點的時候，只能取得第三級選中的序號.....而第一，第二級依然無法擷取其序號。

main.xml源碼如下：

<?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="兩層結構"
   android:layout_width="160dip" android:id="@+id/btnNormal"></Button>
  <Button android:layout_height="wrap_content" android:text="三層結構"
   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是主類，調用其他工具類，源碼如下：

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同學", "xxxxx女人"};
    public String[][]  child= {
            { "A君", "B君", "C君", "D君" },
            { "同學甲", "同學乙", "同學丙"},
            { "禦姐", "蘿莉" }
    };
   
    public String[] parent = { "xxxx好友", "xxxx同學"};
    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練習----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++)//第一層
          {
           SuperTreeViewAdapter.SuperTreeNode superNode=new SuperTreeViewAdapter.SuperTreeNode();
           superNode.parent=parent[i];
           
           //第二層
           for(int ii=0;ii<child_grandson.length;ii++)
              {
               TreeViewAdapter.TreeNode node=new TreeViewAdapter.TreeNode();
               node.parent=child_grandson[ii][0][0];//第二級菜單的標題
               
               for(int iii=0;iii<child_grandson[ii][1].length;iii++)//第三級菜單
               {
                node.childs.add(child_grandson[ii][1][iii]);
               }
               superNode.childs.add(node);
              }
           superTreeNode.add(superNode);
           
          }
          superAdapter.UpdateTreeNode(superTreeNode);
          expandableList.setAdapter(superAdapter);
   }
  }
    }

    /**
     * 三級樹形菜單的事件不再可用，本函數由三級樹形菜單的子項（二級菜單）進行回調
     */
    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是實現二級樹形菜單的工具類，源碼如下：

 

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;//每項的高度
 public static final int PaddingLeft=36;//每項的高度
 private int myPaddingLeft=0;//如果是由SuperTreeView調用，則作為子項需要往右移

 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是實現三級樹形菜單的工具類，會用到TreeViewAdapter.java，源碼如下：

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;
  //二級樹形菜單的結構體
  List<TreeViewAdapter.TreeNode> childs = new ArrayList<TreeViewAdapter.TreeNode>();
 }

 private List<SuperTreeNode> superTreeNodes = new ArrayList<SuperTreeNode>();
 private Context parentContext;
 private OnChildClickListener stvClickEvent;//外部回呼函數
 
 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;
 }

 /**
  * 三層樹結構中的第二層是一個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();//臨時變數取得TreeViewAdapter的TreeNode集合，可為空白
  final TreeNode treeNode=(TreeNode) getChild(groupPosition, childPosition);
  tmp.add(treeNode);
  treeViewAdapter.UpdateTreeNode(tmp);
  treeView.setAdapter(treeViewAdapter);
  
  //關鍵點：取得選中的二級樹形菜單的父子節點,結果返回給外部回呼函數
  treeView.setOnChildClickListener(this.stvClickEvent);
  
  /**
   * 關鍵點：第二級菜單展開時通過取得節點數來設定第三級菜單的大小
   */
  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);
   }
  });
  
  /**
   * 第二級菜單回收時設定為標準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;
 }

 /**
  * 三級樹結構中的首層是TextView,用於作為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;
 }
}

總結，使用ExpandableList實現三級樹形菜單時有些bug不好解決，而且定義三維數組的時候也要倍加小心......所以盡量把資料化簡來使用二級樹形菜單。