Android树形控件的实现方法

在pc上我们已经习惯了树形控件，因为其可以清晰的展现各个节点之间的层次结果，但是在android平台上，系统并没有提供这样一个控件，而是只有listview。不过通过改写与listview绑定的adapter可以实现这样一个效果。

 一个listview需要和一个adapter绑定，用于管理数据。在这里以baseadapter为例，继承adapter需要重写四个函数，其中较为重要的是两个：
   1 public int getcount()；//该函数返回listview 的listitem的条数
   2 public view getview(int position, view view, viewgroup arg2)//负责绘制每一个item。如果getcount（）返回10，那么getview（）就会被调用10次。

首先开发自己的数据结构：

package bupt.liyazhou.ui; 
 
import java.util.arraylist; 
import java.util.list; 
 
/* 
 * @ author:liyazhou 
 * @date:2013.4.29 
 * @description:node类用来在ui层中存储一个节点的信息 
 * 
 */ 
public class node { 
 private node parent=null;//父节点 
 private list<node> children=null; 
 private string oid=null;//该节点的oid 
 private string name=null;//该节点信息的描述 
 private string value=null;//该节点的值 
 private boolean isleaf=false;//是否为叶节点 
 private boolean isexpanded=false;//该节点是否展开 
 private int icon=-1;//该节点的图标对应的id 
 private int iconforexpandedorfolded=-1; 
 private int iconforexpanding=-1; 
 private int iconforfolding=-1; 
 private boolean tableitemornot=false;//表示是否为表结构的一列 
  
 public node(node parent,string oid,string description,boolean isleaf,int icon,int exicon,int foicon) 
 { 
  this.parent=parent; 
  this.oid=oid; 
  this.name=description; 
  this.isleaf=isleaf; 
  this.icon=icon; 
  this.iconforexpanding=exicon; 
  this.iconforfolding=foicon; 
 } 
 public void settableitemornot(boolean tableitemornot) 
 { 
  this.tableitemornot=tableitemornot; 
 } 
 public boolean gettableitemornot() 
 { 
  return this.tableitemornot; 
 } 
 //设置value 
 public void setvalue(string value) 
 { 
  this.value=value; 
 } 
 //得到value 
 public string getvalue() 
 { 
  return this.value; 
 } 
 //设置图标 
 public void seticon(int icon) 
 { 
  this.icon=icon; 
 } 
 public int geticon() 
 { 
  return this.icon; 
 } 
 //得到description 
 public string getdescription() 
 { 
  return this.name; 
 } 
 //得到oid 
 public string getoid() 
 { 
  return this.oid; 
 } 
 //得到是否为叶节点 
 public boolean isleafornot() 
 { 
  return this.isleaf; 
 } 
 //得到当前节点所在的层数，根为0层 
 public int getlevel() 
 { 
  return parent==null?0:parent.getlevel()+1; 
 } 
 //设置是否展开 
 public void setexpanded(boolean isexpanded) 
 { 
  this.isexpanded=isexpanded; 
 } 
 public boolean getexpanded() 
 { 
  return this.isexpanded; 
 } 
 //添加子节点 
 public void addchildnode(node child) 
 { 
  if(this.children==null) 
  { 
   this.children=new arraylist<node>(); 
  } 
  this.children.add(child); 
 } 
 //清空子节点 
 public void clearchildren() 
 { 
  if(!this.children.equals(null)) 
  { 
   this.children.clear(); 
  } 
 } 
 //是否为根节点 
 public boolean isroot() 
 { 
  return this.parent.equals(null)?true:false; 
 } 
 //设置展开图标 
 public void setexpandicon(int expand) 
 { 
  this.iconforexpanding=expand; 
 } 
 //设置折叠图标 
 public void setfoldicon(int fold) 
 { 
  this.iconforfolding=fold; 
 } 
 //得到展开或折叠图标 
 public int getexpandorfoldicon() 
 { 
  if(this.isexpanded==true) 
   return this.iconforexpanding; 
  else 
   return this.iconforfolding; 
 } 
 //得到子树 
 public list<node> getchildren() 
 { 
  return this.children; 
 } 
} 

然后写自己的adapter

package bupt.liyazhou.ui; 
 
import java.util.arraylist; 
import java.util.list; 
 
import android.r; 
import android.content.context; 
import android.view.layoutinflater; 
import android.view.view; 
import android.view.viewgroup; 
import android.widget.baseadapter; 
import android.widget.imageview; 
import android.widget.textview; 
import android.widget.toast; 
 
public class mibtreelistadapter extends baseadapter { 
 private context context=null; 
 private list<node> nodelist=new arraylist<node> ();//所有的节点 
 private list<node> nodelisttoshow=new arraylist<node>();//要展现的节点 
 private layoutinflater inflater=null; 
 private node root=null; 
  
 public mibtreelistadapter(context con,node root,int layout) 
 { 
  this.context=con; 
  this.inflater=(layoutinflater)con.getsystemservice(context.layout_inflater_service); 
  establishnodelist(root); 
  this.root=root; 
  setnodelisttoshow(); 
 } 
 public void establishnodelist(node node) 
 { 
  nodelist.add(node); 
  if(node.isleafornot()) 
   return; 
  list<node> children=node.getchildren(); 
  for(int i=0;i<children.size();i++) 
  { 
   establishnodelist(children.get(i)); 
  } 
 } 
 public void setnodelisttoshow() 
 { 
  this.nodelisttoshow.clear(); 
  establishnodelisttoshow(this.root); 
 } 
  
  
 //构造要展示在listview的nodelisttoshow 
 public void establishnodelisttoshow(node node) 
 { 
  this.nodelisttoshow.add(node); 
  if(node.getexpanded()&&!node.isleafornot()&&node.getchildren()!=null) 
  { 
   list<node> children=node.getchildren(); 
   for(int i=0;i<children.size();i++) 
   { 
    establishnodelisttoshow(children.get(i)); 
   } 
  } 
 } 
  
 //根据oid得到某一个node,并更改其状态 
 public void changenodeexpandorfold(int position) 
 { 
  string oid=this.nodelisttoshow.get(position).getoid(); 
  for(int i=0;i<this.nodelist.size();i++) 
  { 
   if(nodelist.get(i).getoid().equals(oid)) 
   { 
    boolean flag=nodelist.get(i).getexpanded(); 
    nodelist.get(i).setexpanded(!flag); 
   } 
    
  } 
 } 
  
 //listitem被点击的响应事件 
 public node onlistitemclick(int position) 
 { 
  node node=this.nodelisttoshow.get(position); 
  if(node.isleafornot()) 
  { 
   //处理snmp代码 
   toast.maketext(this.context, "该节点为子节点", toast.length_short).show(); 
   return node; 
  } 
  else 
  { 
   this.changenodeexpandorfold(position); 
   this.setnodelisttoshow(); 
   this.notifydatasetchanged(); 
   return null; 
  } 
 } 
 public int getcount() { 
  // todo auto-generated method stub 
  return nodelisttoshow.size(); 
 } 
 
 public object getitem(int arg0) { 
  // todo auto-generated method stub 
  return nodelisttoshow.get(arg0); 
 } 
 
 public long getitemid(int arg0) { 
  // todo auto-generated method stub 
  return arg0; 
 } 
 
 public view getview(int position, view view, viewgroup parent) { 
  // todo auto-generated method stub 
  holder holder=null; 
  if(view!=null) 
  { 
   holder=(holder)view.gettag(); 
  } 
  else 
  { 
   holder=new holder(); 
   view=this.inflater.inflate(bupt.liyazhou.r.layout.listview_item, null); 
   holder.description=(textview)view.findviewbyid(bupt.liyazhou.r.id.textview_nodedescription); 
   holder.nodeicon=(imageview)view.findviewbyid(bupt.liyazhou.r.id.imageview_nodeimage); 
   holder.expandorfoldicon=(imageview)view.findviewbyid(bupt.liyazhou.r.id.imageview_expandedimage); 
   view.settag(holder); 
  } 
   
  //绘制一个item 
   
  //设置文字 
  node node= this.nodelisttoshow.get(position); 
  holder.description.settext(node.getdescription()); 
   
  //设置图标 
  int icon=node.geticon(); 
  if(icon!=-1) 
  { 
   holder.nodeicon.setimageresource(icon); 
   holder.nodeicon.setvisibility(view.visible); 
  } 
  else 
   holder.nodeicon.setvisibility(view.invisible); 
   
  //设置展开折叠图标 
  if(!node.isleafornot()) 
  { 
   int expandicon=node.getexpandorfoldicon(); 
   if(expandicon==-1) 
    holder.expandorfoldicon.setvisibility(view.invisible); 
   else 
   { 
    holder.expandorfoldicon.setimageresource(expandicon); 
    holder.expandorfoldicon.setvisibility(view.visible); 
   } 
   
  } 
  else 
  { 
   holder.expandorfoldicon.setvisibility(view.invisible); 
  } 
  view.setpadding(node.getlevel()*35, 10, 10, 10); 
  return view; 
 } 
  
 public class holder 
 { 
  textview description; 
  imageview nodeicon; 
  imageview expandorfoldicon; 
 } 
 
} 

listview_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/imageview_nodeimage" 
  android:layout_height="fill_parent" 
  android:layout_width="wrap_content" 
  android:layout_alignparentleft="true" 
  android:paddingright="10dp"/> 
 <textview 
  android:id="@+id/textview_nodedescription" 
  android:layout_height="fill_parent" 
  android:layout_width="wrap_content" 
  android:layout_torightof="@id/imageview_nodeimage" 
  /> 
 <imageview 
  android:id="@+id/imageview_expandedimage" 
  android:layout_height="fill_parent" 
  android:layout_width="wrap_content" 
  android:layout_alignparentright="true"/> 
 
  
 
</relativelayout> 

实现效果：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。