tv_title.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener()
    {
      @Override
      public void onGlobalLayout()
      {
        mTitleTopAndHeight = tv_title.getTop();

        tv_title.getViewTreeObserver().removeGlobalOnLayoutListener(this);
      }
    });

   tv_title.post(new Runnable()
    {
      @Override
      public void run()
      {
        mTitleTopAndHeight = tv_title.getTop();
      }
    });

public class MyScrollView extends ScrollView
{
  private OnScrollListener mOnScrollListener;

  /**
   * 是否用户手指触摸滑动
   */
  private boolean mIsTouch = false;

  public MyScrollView(Context context)
  {
    this(context, null);
  }

  public MyScrollView(Context context, AttributeSet attrs)
  {
    this(context, attrs, 0);
  }

  public MyScrollView(Context context, AttributeSet attrs, int defStyleAttr)
  {
    super(context, attrs, defStyleAttr);
  }

  @Override
  protected void onScrollChanged(int l, int t, int oldl, int oldt)
  {
    super.onScrollChanged(l, t, oldl, oldt);

    if (mOnScrollListener != null)
    {
      mOnScrollListener.onScroll(t, mIsTouch ? OnScrollListener.SCROLL_STATE_TOUCH_SCROLL : OnScrollListener.SCROLL_STATE_FLING);
    }
  }

  @Override
  public boolean onTouchEvent(MotionEvent ev)
  {
    switch (ev.getAction())
    {
      case MotionEvent.ACTION_MOVE:
        mIsTouch = true;

        break;
      case MotionEvent.ACTION_UP:
      case MotionEvent.ACTION_CANCEL:
        mIsTouch = false;

        break;
    }

    return super.onTouchEvent(ev);
  }

  public void setOnScrollListener(OnScrollListener onScrollListener)
  {
    mOnScrollListener = onScrollListener;
  }

  public interface OnScrollListener
  {
    /**
     * 用户手指拖动滚动
     */
    int SCROLL_STATE_TOUCH_SCROLL = 0x0;

    /**
     * 惯性滑行滚动
     */
    int SCROLL_STATE_FLING = 0x1;

    /**
     * 滚动时的回调
     *
     * @param scrollY   Y方向滚动的距离
     * @param scroll_state 当前滚动状态：自由滚动或者手势拖动滚动
     */
    void onScroll(int scrollY, int scroll_state);
  }
}

  mScrollView.setOnScrollListener(new MyScrollView.OnScrollListener()
    {
      @Override
      public void onScroll(int scrollY, int state)
      {
        Log.d("onScroll: ", scrollY + "" + "----------- state:" + state);

        if (scrollY <= mTitleTopAndHeight)
        {
          tv_float.setVisibility(View.INVISIBLE);
        } else
        {
          tv_float.setVisibility(View.VISIBLE);
        }
      }
    });

    tv_float.setOnTouchListener(new View.OnTouchListener()
    {
      @Override
      public boolean onTouch(View v, MotionEvent event)
      {
        mScrollView.onTouchEvent(event);
        return false;
      }
    });

<?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"
  >

  <com.example.qike.scrolltitle.MyScrollView
    android:id="@+id/sv_main"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical">

      <TextView
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:gravity="center"
        android:text="商品图片"/>

      <TextView
        android:id="@+id/tv_title"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:background="#a3c"
        android:gravity="center"
        android:text="标题view"/>

      <TextView
        android:layout_width="match_parent"
        android:layout_height="600dp"
        android:background="#a2bb"
        android:gravity="center"
        android:text="详情页面"/>
    </LinearLayout>
  </com.example.qike.scrolltitle.MyScrollView>

  <TextView
    android:id="@+id/tv_float"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:background="#a3c"
    android:gravity="center"
    android:text="标题view"
    android:visibility="invisible"/>

</RelativeLayout>

 mScrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener()
    {
      @Override
      public void onScrollChanged()
      {
        int scrollY = mScrollView.getScrollY();
        if (scrollY <= mTitleTopAndHeight)
        {
          tv_float.setVisibility(View.INVISIBLE);
        } else
        {
          tv_float.setVisibility(View.VISIBLE);
        }
      }
    });