Android树形控件的实现方法

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;  } } 

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;  }  } 

<?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>