android ListView 实现3级节点 （可拓展N级）

            ListView实现二级节点想必大家都知道可以用ExpandableListView 就可以轻松实现，但是要实现3级甚至多级菜单怎么实现呢？ 再利用ExpandableListView 就会十分繁琐，今天我们来探究另一种实现方式来实现。

          思路：每次点击展开子菜单 ，可以理解为 listView的一次重绘（数据更新<增加子节点数据>），而收起子菜单就是移除当前节点下的子数据，这是数据更新。对于界面每一个itemView的实现可以在adapter里面实现，根据没个子元素的级别，是否含有子节点，是否已经展开来配置不同的界面显示效果。首先来看实现的效果：

1：首先看子元素bean

package com.example.androidexpandablelistview;import java.util.ArrayList;import java.util.List;/** * 元素 可根据需要添加新的属性  * @author jrh * */public class TreeElement {/** * 各个元素的层级标识 */private int parentLevel;/** * 节点显示标题 */private String noteName;/** * 子节点元素集合 */private ArrayList<TreeElement> dataList = new ArrayList<TreeElement>();/** * 是否已扩展 */private boolean isExpandAble;/** * 是否有子节点元素 */private boolean isHasChild;/** * 当前节点位置 */private int position;/** *  * @param parentLevel 各个元素的层级标识 * @param noteName 节点显示标题 * @param dataList 子节点元素集合 * @param isExpandAble 是否已扩展 * @param isHasChild 是否有子节点元素 * @param position 当前节点位置 */public TreeElement(int parentLevel, String noteName,ArrayList<TreeElement> dataList, boolean isExpandAble,boolean isHasChild, int position) {super();this.parentLevel = parentLevel;this.noteName = noteName;this.dataList = dataList;this.isExpandAble = isExpandAble;this.isHasChild = isHasChild;this.position = position;}public int getPosition() {return position;}public void setPosition(int position) {this.position = position;}public boolean isHasChild() {return isHasChild;}public void setHasChild(boolean isHasChild) {this.isHasChild = isHasChild;}public int getParentLevel() {return parentLevel;}public void setParentLevel(int parentLevel) {this.parentLevel = parentLevel;}public String getNoteName() {return noteName;}public void setNoteName(String noteName) {this.noteName = noteName;}public ArrayList<TreeElement> getDataList() {return dataList;}public void setDataList(ArrayList<TreeElement> dataList) {this.dataList = dataList;}public boolean isExpandAble() {return isExpandAble;}public void setExpandAble(boolean isExpandAble) {this.isExpandAble = isExpandAble;}}

2：数据更新adapter

package com.example.androidexpandablelistview;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;/** * 处理点击 数据更新 通用 * @author jrh * */public class TreeAdapter extends BaseAdapter {private List<TreeElement> mParentList;private Context context;public TreeAdapter(List<TreeElement> parentList, Context context) {super();this.mParentList = parentList;this.context = context;}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn mParentList == null ? 0 : mParentList.size();}@Overridepublic Object getItem(int arg0) {// TODO Auto-generated method stubreturn mParentList == null ? null : mParentList.get(arg0);}@Overridepublic long getItemId(int arg0) {// TODO Auto-generated method stubreturn arg0;}@Overridepublic View getView(int arg0, View arg1, ViewGroup arg2) {// TODO Auto-generated method stubreturn null;}public void onExpandClick(int position) {// 父节点没有子元素直接返回if (!mParentList.get(position).isHasChild()) {return;}// 父节点已经扩展if (mParentList.get(position).isExpandAble()) {mParentList.get(position).setExpandAble(false);TreeElement element = mParentList.get(position);// 遍历已扩展的元素，删除ArrayList<TreeElement> temp = new ArrayList<TreeElement>();// 从当前点的下一个元素开始隐藏for (int i = position + 1; i < mParentList.size(); i++) {if (element.getParentLevel() >= mParentList.get(i).getParentLevel()) {break;}temp.add(mParentList.get(i));}mParentList.removeAll(temp);for (int i = position + 1; i < mParentList.size(); i++) {mParentList.get(i).setPosition(i);}notifyDataSetChanged();} else {// 父节点为点开TreeElement objElement = mParentList.get(position);objElement.setExpandAble(true);int level = objElement.getParentLevel();int nextLevel = level + 1;ArrayList<TreeElement> tempList = objElement.getDataList();//扩充父类集合for (int i = 0; i < tempList.size(); i++) {TreeElement element = tempList.get(i);element.setParentLevel(nextLevel);element.setExpandAble(false);mParentList.add(position+1,element);}for (int i = position+1; i <mParentList.size(); i++) {mParentList.get(i).setPosition(i);}notifyDataSetChanged();}}}

3：具体适配adapter

package com.example.androidexpandablelistview;import java.util.List;import android.content.Context;import android.graphics.Color;import android.graphics.drawable.LayerDrawable;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.RelativeLayout;import android.widget.TextView;/** * 具体子adapter 可根据不同的要求自定义 * @author jrh * */public class DetaiTreeAdapter extends TreeAdapter {private LayoutInflater inflater;private List<TreeElement> mParentList;public DetaiTreeAdapter(List<TreeElement> parentList, Context context) {super(parentList, context);inflater = LayoutInflater.from(context);mParentList = parentList;}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn super.getCount();}@Overridepublic Object getItem(int arg0) {// TODO Auto-generated method stubreturn super.getItem(arg0);}@Overridepublic long getItemId(int arg0) {// TODO Auto-generated method stubreturn super.getItemId(arg0);}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {// TODO Auto-generated method stub// hodler 需为局部变量ViewHodler hodler = new ViewHodler();TreeElement treeElement = mParentList.get(position);if (convertView == null) {convertView = inflater.inflate(R.layout.itemview, null);hodler.icon = (ImageView) convertView.findViewById(R.id.ic_img);hodler.title = (TextView) convertView.findViewById(R.id.title_tv);hodler.connection = (RelativeLayout) convertView.findViewById(R.id.layout_treeview_connection);convertView.setTag(hodler);} else {hodler = (ViewHodler) convertView.getTag();}// "-"; "+";图标处理if (treeElement.isHasChild()) {if (treeElement.isExpandAble()) {if (treeElement.getParentLevel() == 0) {hodler.icon.setImageResource(R.drawable.knowledgetree_rootexpanded);} else {hodler.icon.setImageResource(R.drawable.knowledgetree_expanded);}} else {if (treeElement.getParentLevel() == 0) {hodler.icon.setImageResource(R.drawable.knowledgetree_rootunexpanded);} else {hodler.icon.setImageResource(R.drawable.knowledgetree_unexpanded);}}} else {hodler.icon.setImageResource(R.drawable.knowledgetree_leaf);}// 设置 展开 时，“-”、“+”间的连线if (treeElement.getParentLevel() == 0) {if (position + 1 < getCount()&& mParentList.get(position + 1).getParentLevel() == 0) {hodler.connection.setBackgroundResource(0);} else if (position + 1 == getCount()) {hodler.connection.setBackgroundResource(0);} else {hodler.connection.setBackgroundResource(R.drawable.knowledgetree_halfconnection_root);}} else {if (position + 1 < getCount()&& mParentList.get(position + 1).getParentLevel() == 0) {hodler.connection.setBackgroundResource(R.drawable.knowledgetree_halfconnection_leaf);} else if (position == getCount() - 1)hodler.connection.setBackgroundResource(R.drawable.knowledgetree_halfconnection_leaf);elsehodler.connection.setBackgroundResource(R.drawable.knowledgetree_connection);}// 标题背景设置if (treeElement.getParentLevel() == 0) {hodler.title.setBackgroundColor(Color.BLUE);hodler.title.setPadding(8, 8, 8, 8);} else if (treeElement.getParentLevel() == 1) {hodler.title.setBackgroundColor(Color.RED);hodler.title.setPadding(38, 8, 8, 8);} else if (treeElement.getParentLevel() == 2) {hodler.title.setPadding(78, 8, 8, 8);hodler.title.setBackgroundColor(Color.GRAY);}hodler.title.setTextColor(Color.WHITE);hodler.title.setText(treeElement.getNoteName());return convertView;}@Overridepublic void onExpandClick(int position) {super.onExpandClick(position);}class ViewHodler {ImageView icon;TextView title;RelativeLayout connection;}}

4：主界面

package com.example.androidexpandablelistview;import java.util.ArrayList;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.view.Window;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.ListView;public class MainActivity extends Activity {private ListView mLv;private DetaiTreeAdapter adapter;private ArrayList<TreeElement> dataList;private ArrayList<TreeElement> seconddataList;private ArrayList<TreeElement> thirddataList;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);initView();initData();initEvent();}/** * 事件处理 */private void initEvent() {mLv.setOnItemClickListener(new OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {adapter.onExpandClick(arg2);}});}/** * 数据加载 */private void initData() {dataList  = new ArrayList<TreeElement>();seconddataList = new ArrayList<TreeElement>();thirddataList = new ArrayList<TreeElement>();adapter = new DetaiTreeAdapter(dataList, MainActivity.this);mLv.setAdapter(adapter);//模拟三级节点数据for (int i = Data.thridTitle.length-1; i >=0; i--) {TreeElement element = new TreeElement(2, Data.thridTitle[i], new ArrayList<TreeElement>(),false, false, i);thirddataList.add(element);}//模拟二级节点数据for (int i = Data.secondTitle.length-1; i >=0; i--) {TreeElement element = new TreeElement(1, Data.secondTitle[i],i == 0 ? thirddataList : null, false,i == 0 ? true : false, i);seconddataList.add(element);}//模拟一级节点数据for (int i = 0; i < Data.title.length; i++) {TreeElement element = new TreeElement(0, Data.title[i],i == 0 ? seconddataList : null, false, i == 0 ? true: false, i);dataList.add(element);}adapter.notifyDataSetChanged();}private void initView() {mLv = (ListView) findViewById(R.id.lv);}}

5：模拟数据

package com.example.androidexpandablelistview;/** * 模拟数据 * @author jrh * */public class Data {public static String title[] = {"常识判断","言语理解","数量关系","判断推理","资料分析"};public static String secondTitle[]={"政治","经济","法律","历史","人文"};public static String thridTitle[] ={"时政","马克思主义哲学","中共党史","中国特色社会主义体系"};}

6：界面布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <ListView        android:id="@+id/lv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"         /></RelativeLayout>

7：itemView

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:gravity="center|left"    android:orientation="horizontal"    android:paddingLeft="8dp" >    <RelativeLayout        android:layout_width="wrap_content"        android:layout_height="fill_parent" >        <RelativeLayout            android:id="@+id/layout_treeview_connection"            android:layout_width="wrap_content"            android:layout_height="match_parent"            >            <ImageView                android:id="@+id/img_treeview_ico"                android:layout_width="wrap_content"                android:layout_height="match_parent"                android:layout_centerInParent="true"                android:scaleType="fitXY"                android:contentDescription="@string/app_name" />        </RelativeLayout>        <ImageView            android:id="@+id/ic_img"              android:layout_centerInParent="true"            android:layout_width="wrap_content"            android:layout_height="wrap_content"           />    </RelativeLayout>    <TextView        android:id="@+id/title_tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:padding="8dp"        android:textSize="18sp" /></LinearLayout>

示例代码下载