Android中如何实现清空搜索框的文字

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:orientation="vertical" 
 android:paddingBottom="50dp" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent"> 
 <RelativeLayout android:id="@+id/top" 
  android:layout_width="fill_parent" 
  android:layout_alignParentTop="true" 
  android:paddingLeft="10dp" 
  android:paddingRight="10dp"   android:background="@drawable/top_background" 
  android:layout_height="wrap_content"> 
  <Button android:id="@+id/btnSearch" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:gravity="center" 
   android:layout_centerVertical="true" 
   android:layout_alignParentRight="true" 
   android:textSize="12sp" 
   android:textStyle="bold"   android:background="@drawable/search_btn_background" 
   android:text="搜索"/> 
  <RelativeLayout android:id="@+id/rlSearchFrameDelete" 
   android:layout_width="fill_parent" 
   android:layout_height="wrap_content" 
   android:layout_centerVertical="true" 
   android:gravity="center_vertical" 
android:layout_toLeftOf="@id/btnSearch"> 
    <EditText android:id="@+id/etSearch" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:singleLine="true" 
android:background="@drawable/search_frame"   android:layout_marginRight="10dp" 
     android:paddingLeft="32dp" 
     android:textSize="12sp" 
     android:hint="请输入文字..."/> 
    <ImageView android:id="@+id/ivDeleteText"     android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:layout_alignParentRight="true" 
     android:src="@drawable/delete" 
 android:layout_centerInParent="true" 
     android:paddingRight="20dp" 
     android:visibility="gone"/> 
  </RelativeLayout> 
 </RelativeLayout> 
</RelativeLayout> 

[java] view plain copy
public void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_main); 
  ivDeleteText = (ImageView) findViewById(R.id.ivDeleteText); 
  etSearch = (EditText) findViewById(R.id.etSearch); 
  ivDeleteText.setOnClickListener(new OnClickListener() { 
   public void onClick(View v) { 
    etSearch.setText(""); 
   } 
  }); 
  etSearch.addTextChangedListener(new TextWatcher() { 
   public void onTextChanged(CharSequence s, int start, int before, int count) { 
    // TODO Auto-generated method stub 
   } 
   public void beforeTextChanged(CharSequence s, int start, int count, 
     int after) { 
    // TODO Auto-generated method stub 
   } 
   public void afterTextChanged(Editable s) { 
    if (s.length() == 0) { 
     ivDeleteText.setVisibility(View.GONE); 
    } else { 
     ivDeleteText.setVisibility(View.VISIBLE); 
    } 
   } 
  });