<?xml version="1.0" encoding="utf-8"?> 
<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="com.znke.pulltorefresh_top.MainActivity"> 
 
 <!--<com.znke.pulltorefresh_top.tool.ToTopScrollView .../>--> 
 <ScrollView 
  android:id="@+id/scrollView" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  android:layout_below="@+id/tv_top" 
  android:scrollbars="none"> 
 
  <LinearLayout 
   android:layout_width="match_parent" 
   android:layout_height="wrap_content" 
   android:orientation="vertical"> 
 
   <TextView 
    android:layout_width="match_parent" 
    android:layout_height="50dp" 
    android:gravity="center" 
    android:text="111111111111" 
    android:textSize="20sp" /> 
 
   ........... 
 
   <View 
    android:layout_width="match_parent" 
    android:layout_height="2dp" 
    android:background="#AAAAAA" /> 
 
   <TextView 
    android:layout_width="match_parent" 
    android:layout_height="80dp" 
    android:gravity="center" 
    android:text="12000000000000" 
    android:textSize="20sp" /> 
  </LinearLayout> 
 </ScrollView> 
 
 <com.znke.pulltorefresh_top.tool.ToTopImageView 
  android:id="@+id/imageView_to_top" 
  android:layout_width="50dp" 
  android:layout_height="50dp" 
  android:layout_alignParentBottom="true" 
  android:layout_alignParentRight="true" 
  android:layout_marginBottom="5dp" 
  android:layout_marginRight="5dp" 
  android:background="@drawable/to_top" /> 
</RelativeLayout> 

mScrollView.setOnScrollChangeListener(); 

public class ToTopScrollView extends ScrollView { 
 private OnMyScrollListener onMyScrollListener; 
 
 public void setOnMyScrollListener(OnMyScrollListener onMyScrollListener) { 
  this.onMyScrollListener = onMyScrollListener; 
 } 
 
 ... 
 
 @Override 
 protected void onScrollChanged(int l, int t, int oldl, int oldt) { 
  super.onScrollChanged(l, t, oldl, oldt); 
  if(onMyScrollListener != null) 
   onMyScrollListener.onScrollChanged(l,t,oldl,oldt); 
 } 
 
 public interface OnMyScrollListener{ 
  void onScrollChanged(int x, int y, int oldx, int oldy); 
 } 
} 

mScrollView.setOnTouchListener() 

  @Override 
protected ScrollView createRefreshableView(Context context, AttributeSet attrs) { 
 ScrollView scrollView; 
 if (VERSION.SDK_INT >= VERSION_CODES.GINGERBREAD) { 
  scrollView = new InternalScrollViewSDK9(context, attrs); 
 } else { 
  scrollView = new ScrollView(context, attrs); 
 } 
 
 scrollView.setId(R.id.scrollview); 
 return scrollView; 
} 

final ScrollView scrollView = mScrollView.getRefreshableView(); 

/** 
  * 获取待监控的view对象 
  * 实时调起线程，监控是否scroll停止，来判断是否需要显示imageView 
  * @param targetView 需要监控的对象 
  */ 
 public void tellMe(View targetView) { 
  if (targetView == null) 
   throw new IllegalArgumentException("please set targetView who to scrollTo"); 
  if (this.targetView == null) 
   this.targetView = targetView; 
  if (!isStarting) { 
   new Thread(scanThread).start(); 
  } 
 } 

private class MyCallback implements Runnable { 
  @Override 
  public void run() { 
   /** 
    * 获取实时的卷动值，不要传递scroll值给我 
    */ 
   endScrollX = targetView.getScrollX(); 
   int scrollY = targetView.getScrollY(); 
   if (endScrollY != scrollY) { 
    endScrollY = scrollY; 
   } else { 
    if (endScrollY >= limitHeight) { 
     if (!thisStateVisible) 
      visible(); 
    } else { 
     if (thisStateVisible) 
      gone(); 
    } 
    /** 
     * 已判定，卷动停止，显示或隐藏当前view已完成 
     * 退出监控scroll线程 
     */ 
    clearCallBacks(); 
   } 
  } 
 } 

private PullToRefreshScrollView mScrollView; 
 private ToTopImageView imageView_to_top; 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_pull_to_refresh_scroll_view); 
 
  imageView_to_top = (ToTopImageView) findViewById(R.id.imageView_to_top); 
  imageView_to_top.setLimitHeight(800); 
  mScrollView = (PullToRefreshScrollView) findViewById(R.id.scrollView); 
  final ScrollView scrollView = mScrollView.getRefreshableView(); 
  //mScrollView.setOnTouchListener(); 无效 
  scrollView.setOnTouchListener(new View.OnTouchListener() { 
   @Override 
   public boolean onTouch(View v, MotionEvent event) { 
    switch (event.getAction()){ 
     case MotionEvent.ACTION_MOVE: 
      imageView_to_top.tellMe(scrollView); 
      break; 
    } 
    return false; 
   } 
  }); 
 } 
 
 @Override 
 protected void onDestroy() { 
  imageView_to_top.clearCallBacks(); 
  super.onDestroy(); 
 } 

<com.znke.pulltorefresh_top.tool.ToTopImageView 
  android:id="@+id/imageView_to_top" 
  android:layout_width="50dp" 
  android:layout_height="50dp" 
  android:layout_alignParentBottom="true" 
  android:layout_alignParentRight="true" 
  android:layout_marginBottom="5dp" 
  android:layout_marginRight="5dp" 
  android:background="@drawable/to_top" />