Android(安卓)UI 之实现多级列表TreeView

所谓TreeView就是在Windows中常见的多级列表树，在Android中系统只默认提供了ListView和ExpandableListView两种列表，最多只支持到二级列表的实现，所以如果想要实现三级和更多层次的列表，就需要我们自己来做一些处理了。

其实这个效果很久以前就有人想办法实现了，但是实现的效果有一些问题，我的实现思路主要也是来自于网络，但是在其基础上修正了逻辑上的一些错误，做了一些优化。

先来看一下效果：

然后大体说一下思路：

其实这里实现的多级列表只是一个视觉效果，我们看到的分级效果是由于每行的缩进不同造成的。比如在上面的效果中，山东省和广东省是级别最高的层次，山东省下的青岛市作为山东省的子项，我们增加他的左缩进，这样看起来就有了层次感了。其他的层次也是同理。

也就是说，我们只用了一个ListView，工作的重点就在于不断变化ListView显示的数据，根据用户的操作，将数据修改为用户想要看到的数据内容，并根据每个数据项的不同，在显示效果上做不同的缩进处理，最终呈现出一个TreeView的效果。

具体的实现思路参考下面的项目结构和具体代码：

Element.java:

package com.example.androidtreeviewdemo.treeview;/** * Element类 * @author carrey * */public class Element {/** 文字内容 */private String contentText;/** 在tree中的层级 */private int level;/** 元素的id */private int id;/** 父元素的id */private int parendId;/** 是否有子元素 */private boolean hasChildren;/** item是否展开 */private boolean isExpanded;/** 表示该节点没有父元素，也就是level为0的节点 */public static final int NO_PARENT = -1;/** 表示该元素位于最顶层的层级 */public static final int TOP_LEVEL = 0;public Element(String contentText, int level, int id, int parendId,boolean hasChildren, boolean isExpanded) {super();this.contentText = contentText;this.level = level;this.id = id;this.parendId = parendId;this.hasChildren = hasChildren;this.isExpanded = isExpanded;}public boolean isExpanded() {return isExpanded;}public void setExpanded(boolean isExpanded) {this.isExpanded = isExpanded;}public String getContentText() {return contentText;}public void setContentText(String contentText) {this.contentText = contentText;}public int getLevel() {return level;}public void setLevel(int level) {this.level = level;}public int getId() {return id;}public void setId(int id) {this.id = id;}public int getParendId() {return parendId;}public void setParendId(int parendId) {this.parendId = parendId;}public boolean isHasChildren() {return hasChildren;}public void setHasChildren(boolean hasChildren) {this.hasChildren = hasChildren;}}

TreeViewAdapter.java:

package com.example.androidtreeviewdemo.treeview;import java.util.ArrayList;import com.example.androidtreeviewdemo.R;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;/** * TreeViewAdapter * @author carrey * */public class TreeViewAdapter extends BaseAdapter {/** 元素数据源 */private ArrayList<Element> elementsData;/** 树中元素 */private ArrayList<Element> elements;/** LayoutInflater */private LayoutInflater inflater;/** item的行首缩进基数 */private int indentionBase;public TreeViewAdapter(ArrayList<Element> elements, ArrayList<Element> elementsData, LayoutInflater inflater) {this.elements = elements;this.elementsData = elementsData;this.inflater = inflater;indentionBase = 50;}public ArrayList<Element> getElements() {return elements;}public ArrayList<Element> getElementsData() {return elementsData;}@Overridepublic int getCount() {return elements.size();}@Overridepublic Object getItem(int position) {return elements.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder holder = null;if (convertView == null) {holder = new ViewHolder();convertView = inflater.inflate(R.layout.treeview_item, null);holder.disclosureImg = (ImageView) convertView.findViewById(R.id.disclosureImg);holder.contentText = (TextView) convertView.findViewById(R.id.contentText);convertView.setTag(holder);} else {holder = (ViewHolder) convertView.getTag();}Element element = elements.get(position);int level = element.getLevel();holder.disclosureImg.setPadding(indentionBase * (level + 1), holder.disclosureImg.getPaddingTop(), holder.disclosureImg.getPaddingRight(), holder.disclosureImg.getPaddingBottom());holder.contentText.setText(element.getContentText());if (element.isHasChildren() && !element.isExpanded()) {holder.disclosureImg.setImageResource(R.drawable.close);//这里要主动设置一下icon可见，因为convertView有可能是重用了"设置了不可见"的view，下同。holder.disclosureImg.setVisibility(View.VISIBLE);} else if (element.isHasChildren() && element.isExpanded()) {holder.disclosureImg.setImageResource(R.drawable.open);holder.disclosureImg.setVisibility(View.VISIBLE);} else if (!element.isHasChildren()) {holder.disclosureImg.setImageResource(R.drawable.close);holder.disclosureImg.setVisibility(View.INVISIBLE);}return convertView;}/** * 优化Holder * @author carrey * */static class ViewHolder{ImageView disclosureImg;TextView contentText;}}

TreeViewItemClickListener.java:

package com.example.androidtreeviewdemo.treeview;import java.util.ArrayList;import android.view.View;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;/** * TreeView item点击事件 * @author carrey * */public class TreeViewItemClickListener implements OnItemClickListener {/** adapter */private TreeViewAdapter treeViewAdapter;public TreeViewItemClickListener(TreeViewAdapter treeViewAdapter) {this.treeViewAdapter = treeViewAdapter;}@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position,long id) {//点击的item代表的元素Element element = (Element) treeViewAdapter.getItem(position);//树中的元素ArrayList<Element> elements = treeViewAdapter.getElements();//元素的数据源ArrayList<Element> elementsData = treeViewAdapter.getElementsData();//点击没有子项的item直接返回if (!element.isHasChildren()) {return;}if (element.isExpanded()) {element.setExpanded(false);//删除节点内部对应子节点数据，包括子节点的子节点...ArrayList<Element> elementsToDel = new ArrayList<Element>();for (int i = position + 1; i < elements.size(); i++) {if (element.getLevel() >= elements.get(i).getLevel())break;elementsToDel.add(elements.get(i));}elements.removeAll(elementsToDel);treeViewAdapter.notifyDataSetChanged();} else {element.setExpanded(true);//从数据源中提取子节点数据添加进树，注意这里只是添加了下一级子节点，为了简化逻辑int i = 1;//注意这里的计数器放在for外面才能保证计数有效for (Element e : elementsData) {if (e.getParendId() == element.getId()) {e.setExpanded(false);elements.add(position + i, e);i ++;}}treeViewAdapter.notifyDataSetChanged();}}}

MainActivity.java:

package com.example.androidtreeviewdemo;import java.util.ArrayList;import com.example.androidtreeviewdemo.treeview.Element;import com.example.androidtreeviewdemo.treeview.TreeViewAdapter;import com.example.androidtreeviewdemo.treeview.TreeViewItemClickListener;import android.os.Bundle;import android.app.Activity;import android.content.Context;import android.view.LayoutInflater;import android.view.Menu;import android.widget.ListView;public class MainActivity extends Activity {/** 树中的元素集合 */private ArrayList<Element> elements;/** 数据源元素集合 */private ArrayList<Element> elementsData;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);init();ListView treeview = (ListView) findViewById(R.id.treeview);TreeViewAdapter treeViewAdapter = new TreeViewAdapter(elements, elementsData, inflater);TreeViewItemClickListener treeViewItemClickListener = new TreeViewItemClickListener(treeViewAdapter);treeview.setAdapter(treeViewAdapter);treeview.setOnItemClickListener(treeViewItemClickListener);}private void init() {elements = new ArrayList<Element>();elementsData = new ArrayList<Element>();//添加节点  -- 节点名称，节点level，节点id，父节点id，是否有子节点，是否展开//添加最外层节点Element e1 = new Element("山东省", Element.TOP_LEVEL, 0, Element.NO_PARENT, true, false);//添加第一层节点Element e2 = new Element("青岛市", Element.TOP_LEVEL + 1, 1, e1.getId(), true, false);//添加第二层节点Element e3 = new Element("市南区", Element.TOP_LEVEL + 2, 2, e2.getId(), true, false);//添加第三层节点Element e4 = new Element("香港中路", Element.TOP_LEVEL + 3, 3, e3.getId(), false, false);//添加第一层节点Element e5 = new Element("烟台市", Element.TOP_LEVEL + 1, 4, e1.getId(), true, false);//添加第二层节点Element e6 = new Element("芝罘区", Element.TOP_LEVEL + 2, 5, e5.getId(), true, false);//添加第三层节点Element e7 = new Element("凤凰台街道", Element.TOP_LEVEL + 3, 6, e6.getId(), false, false);//添加第一层节点Element e8 = new Element("威海市", Element.TOP_LEVEL + 1, 7, e1.getId(), false, false);//添加最外层节点Element e9 = new Element("广东省", Element.TOP_LEVEL, 8, Element.NO_PARENT, true, false);//添加第一层节点Element e10 = new Element("深圳市", Element.TOP_LEVEL + 1, 9, e9.getId(), true, false);//添加第二层节点Element e11 = new Element("南山区", Element.TOP_LEVEL + 2, 10, e10.getId(), true, false);//添加第三层节点Element e12 = new Element("深南大道", Element.TOP_LEVEL + 3, 11, e11.getId(), true, false);//添加第四层节点Element e13 = new Element("10000号", Element.TOP_LEVEL + 4, 12, e12.getId(), false, false);//添加初始树元素elements.add(e1);elements.add(e9);//创建数据源elementsData.add(e1);elementsData.add(e2);elementsData.add(e3);elementsData.add(e4);elementsData.add(e5);elementsData.add(e6);elementsData.add(e7);elementsData.add(e8);elementsData.add(e9);elementsData.add(e10);elementsData.add(e11);elementsData.add(e12);elementsData.add(e13);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.activity_main, menu);return true;}}

treeview_item.xml:

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >        <ImageView         android:id="@+id/disclosureImg"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerVertical="true"        android:layout_alignParentLeft="true"/>        <TextView         android:id="@+id/contentText"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerVertical="true"        android:layout_toRightOf="@id/disclosureImg"/></RelativeLayout>

activity_main.xml:

<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"    tools:context=".MainActivity" >    <ListView         android:id="@+id/treeview"        android:layout_width="match_parent"        android:layout_height="match_parent"/></RelativeLayout>

转载请注明：http://blog.csdn.net/carrey1989/article/details/10227165

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