Android UI 之實現多級列表TreeView

所謂TreeView就是在Windows中常見的多級列表樹，在Android中系統只默認提供了ListView和ExpandableListView兩種列表，最多只支持到二級列表的實現，所以如果想要實現三級和更多層次的列表，就需要我們自己來做一些處理了。

    其實這個效果很久以前就有人想辦法實現了，但是實現的效果有一些問題，我的實現思路主要也是來自於網絡，但是在其基礎上修正了邏輯上的一些錯誤，做了一些優化。

 然後大體說一下思路：

    其實這裡實現的多級列表只是一個視覺效果，我們看到的分級效果是由於每行的縮進不同造成的。比如在上面的效果中，山東省和廣東省是級別最高的層次，山東省下的青島市作為山東省的子項，我們增加他的左縮進，這樣看起來就有了層次感了。其他的層次也是同理。

    也就是說，我們只用了一個ListView，工作的重點就在於不斷變化ListView顯示的數據，根據用戶的操作，將數據修改為用戶想要看到的數據內容，並根據每個數據項的不同，在顯示效果上做不同的縮進處理，最終呈現出一個TreeView的效果。

    具體的實現思路參考下面的項目結構和具體代碼：

Element.java:

[java]
package com.example.androidtreeviewdemo.treeview; 
/**
 * Element類
 * @author carrey
 *
 */ 
public class Element { 
    /** 文字內容 */ 
    private String contentText; 
    /** 在tree中的層級 */ 
    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是否展開 */ 
    private boolean isExpanded; 
     
    /** 表示該節點沒有父元素，也就是level為0的節點 */ 
    public static final int NO_PARENT = -1; 
    /** 表示該元素位於最頂層的層級 */ 
    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; 
    } 
} 

package com.example.androidtreeviewdemo.treeview;
/**
 * Element類
 * @author carrey
 *
 */
public class Element {
 /** 文字內容 */
 private String contentText;
 /** 在tree中的層級 */
 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是否展開 */
 private boolean isExpanded;
 
 /** 表示該節點沒有父元素，也就是level為0的節點 */
 public static final int NO_PARENT = -1;
 /** 表示該元素位於最頂層的層級 */
 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:

[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 { 
    /** 元素數據源 */ 
    private ArrayList<Element> elementsData; 
    /** 樹中元素 */ 
    private ArrayList<Element> elements; 
    /** LayoutInflater */ 
    private LayoutInflater inflater; 
    /** item的行首縮進基數 */ 
    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; 
    } 
     
    @Override 
    public int getCount() { 
        return elements.size(); 
    } 
 
    @Override 
    public Object getItem(int position) { 
        return elements.get(position); 
    } 
 
    @Override 
    public long getItemId(int position) { 
        return position; 
    } 
 
    @Override 
    public 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); 
            //這裡要主動設置一下icon可見，因為convertView有可能是重用了"設置了不可見"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; 
    } 
     
    /**
     * 優化Holder
     * @author carrey
     *
     */ 
    static class ViewHolder{ 
        ImageView disclosureImg; 
        TextView contentText; 
    } 
} 

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 {
 /** 元素數據源 */
 private ArrayList<Element> elementsData;
 /** 樹中元素 */
 private ArrayList<Element> elements;
 /** LayoutInflater */
 private LayoutInflater inflater;
 /** item的行首縮進基數 */
 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;
 }
 
 @Override
 public int getCount() {
  return elements.size();
 }

 @Override
 public Object getItem(int position) {
  return elements.get(position);
 }

 @Override
 public long getItemId(int position) {
  return position;
 }

 @Override
 public 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);
   //這裡要主動設置一下icon可見，因為convertView有可能是重用了"設置了不可見"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;
 }
 
 /**
  * 優化Holder
  * @author carrey
  *
  */
 static class ViewHolder{
  ImageView disclosureImg;
  TextView contentText;
 }
}
TreeViewItemClickListener.java:

[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點擊事件
 * @author carrey
 *
 */ 
public class TreeViewItemClickListener implements OnItemClickListener { 
    /** adapter */ 
    private TreeViewAdapter treeViewAdapter; 
     
    public TreeViewItemClickListener(TreeViewAdapter treeViewAdapter) { 
        this.treeViewAdapter = treeViewAdapter; 
    } 
     
    @Override 
    public void onItemClick(AdapterView<?> parent, View view, int position, 
            long id) { 
        //點擊的item代表的元素  
        Element element = (Element) treeViewAdapter.getItem(position); 
        //樹中的元素  
        ArrayList<Element> elements = treeViewAdapter.getElements(); 
        //元素的數據源  
        ArrayList<Element> elementsData = treeViewAdapter.getElementsData(); 
         
        //點擊沒有子項的item直接返回  
        if (!element.isHasChildren()) { 
            return; 
        } 
         
        if (element.isExpanded()) { 
            element.setExpanded(false); 
            //刪除節點內部對應子節點數據，包括子節點的子節點...  
            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); 
            //從數據源中提取子節點數據添加進樹，注意這裡只是添加了下一級子節點，為了簡化邏輯  
            int i = 1;//注意這裡的計數器放在for外面才能保證計數有效  
            for (Element e : elementsData) { 
                if (e.getParendId() == element.getId()) { 
                    e.setExpanded(false); 
                    elements.add(position + i, e); 
                    i ++; 
                } 
            } 
            treeViewAdapter.notifyDataSetChanged(); 
        } 
    } 
 
} 

package com.example.androidtreeviewdemo.treeview;

import java.util.ArrayList;

import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
/**
 * TreeView item點擊事件
 * @author carrey
 *
 */
public class TreeViewItemClickListener implements OnItemClickListener {
 /** adapter */
 private TreeViewAdapter treeViewAdapter;
 
 public TreeViewItemClickListener(TreeViewAdapter treeViewAdapter) {
  this.treeViewAdapter = treeViewAdapter;
 }
 
 @Override
 public void onItemClick(AdapterView<?> parent, View view, int position,
   long id) {
  //點擊的item代表的元素
  Element element = (Element) treeViewAdapter.getItem(position);
  //樹中的元素
  ArrayList<Element> elements = treeViewAdapter.getElements();
  //元素的數據源
  ArrayList<Element> elementsData = treeViewAdapter.getElementsData();
  
  //點擊沒有子項的item直接返回
  if (!element.isHasChildren()) {
   return;
  }
  
  if (element.isExpanded()) {
   element.setExpanded(false);
   //刪除節點內部對應子節點數據，包括子節點的子節點...
   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);
   //從數據源中提取子節點數據添加進樹，注意這裡只是添加了下一級子節點，為了簡化邏輯
   int i = 1;//注意這裡的計數器放在for外面才能保證計數有效
   for (Element e : elementsData) {
    if (e.getParendId() == element.getId()) {
     e.setExpanded(false);
     elements.add(position + i, e);
     i ++;
    }
   }
   treeViewAdapter.notifyDataSetChanged();
  }
 }

}
MainActivity.java:

[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 { 
    /** 樹中的元素集合 */ 
    private ArrayList<Element> elements; 
    /** 數據源元素集合 */ 
    private ArrayList<Element> elementsData; 
     
    @Override 
    protected 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>(); 
         
        //添加節點  -- 節點名稱，節點level，節點id，父節點id，是否有子節點，是否展開  
         
        //添加最外層節點  
        Element e1 = new Element("山東省", Element.TOP_LEVEL, 0, Element.NO_PARENT, true, false); 
         
        //添加第一層節點  
        Element e2 = new Element("青島市", Element.TOP_LEVEL + 1, 1, e1.getId(), true, false); 
        //添加第二層節點  
        Element e3 = new Element("市南區", Element.TOP_LEVEL + 2, 2, e2.getId(), true, false); 
        //添加第三層節點  
        Element e4 = new Element("香港中路", Element.TOP_LEVEL + 3, 3, e3.getId(), false, false); 
         
        //添加第一層節點  
        Element e5 = new Element("煙台市", Element.TOP_LEVEL + 1, 4, e1.getId(), true, false); 
        //添加第二層節點  
        Element e6 = new Element("芝罘區", Element.TOP_LEVEL + 2, 5, e5.getId(), true, false); 
        //添加第三層節點  
        Element e7 = new Element("鳳凰台街道", Element.TOP_LEVEL + 3, 6, e6.getId(), false, false); 
         
        //添加第一層節點  
        Element e8 = new Element("威海市", Element.TOP_LEVEL + 1, 7, e1.getId(), false, false); 
         
        //添加最外層節點  
        Element e9 = new Element("廣東省", Element.TOP_LEVEL, 8, Element.NO_PARENT, true, false); 
        //添加第一層節點  
        Element e10 = new Element("深圳市", Element.TOP_LEVEL + 1, 9, e9.getId(), true, false); 
        //添加第二層節點  
        Element e11 = new Element("南山區", Element.TOP_LEVEL + 2, 10, e10.getId(), true, false); 
        //添加第三層節點  
        Element e12 = new Element("深南大道", Element.TOP_LEVEL + 3, 11, e11.getId(), true, false); 
        //添加第四層節點  
        Element e13 = new Element("10000號", Element.TOP_LEVEL + 4, 12, e12.getId(), false, false); 
         
        //添加初始樹元素  
        elements.add(e1); 
        elements.add(e9); 
        //創建數據源  
        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); 
    } 
 
    @Override 
    public 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; 
    } 
 
} 

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 {
 /** 樹中的元素集合 */
 private ArrayList<Element> elements;
 /** 數據源元素集合 */
 private ArrayList<Element> elementsData;
 
 @Override
 protected 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>();
  
  //添加節點  -- 節點名稱，節點level，節點id，父節點id，是否有子節點，是否展開
  
  //添加最外層節點
  Element e1 = new Element("山東省", Element.TOP_LEVEL, 0, Element.NO_PARENT, true, false);
  
  //添加第一層節點
  Element e2 = new Element("青島市", Element.TOP_LEVEL + 1, 1, e1.getId(), true, false);
  //添加第二層節點
  Element e3 = new Element("市南區", Element.TOP_LEVEL + 2, 2, e2.getId(), true, false);
  //添加第三層節點
  Element e4 = new Element("香港中路", Element.TOP_LEVEL + 3, 3, e3.getId(), false, false);
  
  //添加第一層節點
  Element e5 = new Element("煙台市", Element.TOP_LEVEL + 1, 4, e1.getId(), true, false);
  //添加第二層節點
  Element e6 = new Element("芝罘區", Element.TOP_LEVEL + 2, 5, e5.getId(), true, false);
  //添加第三層節點
  Element e7 = new Element("鳳凰台街道", Element.TOP_LEVEL + 3, 6, e6.getId(), false, false);
  
  //添加第一層節點
  Element e8 = new Element("威海市", Element.TOP_LEVEL + 1, 7, e1.getId(), false, false);
  
  //添加最外層節點
  Element e9 = new Element("廣東省", Element.TOP_LEVEL, 8, Element.NO_PARENT, true, false);
  //添加第一層節點
  Element e10 = new Element("深圳市", Element.TOP_LEVEL + 1, 9, e9.getId(), true, false);
  //添加第二層節點
  Element e11 = new Element("南山區", Element.TOP_LEVEL + 2, 10, e10.getId(), true, false);
  //添加第三層節點
  Element e12 = new Element("深南大道", Element.TOP_LEVEL + 3, 11, e11.getId(), true, false);
  //添加第四層節點
  Element e13 = new Element("10000號", Element.TOP_LEVEL + 4, 12, e12.getId(), false, false);
  
  //添加初始樹元素
  elements.add(e1);
  elements.add(e9);
  //創建數據源
  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);
 }

 @Override
 public 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:

[html]
?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> 

<?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:

[html]
<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>