<?xml version="1.0" encoding="UTF-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:orientation="horizontal" 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" > 
 
  <ImageView 
    android:id="@+id/buy_layout" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:background="@drawable/buy" /> 
 
</LinearLayout> 

<LinearLayout 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" 
  android:orientation="vertical" > 
 
   <ImageView 
    android:id="@+id/imageView1" 
    android:scaleType="centerCrop" 
    android:layout_width="match_parent" 
    android:layout_height="45dip" 
    android:src="@drawable/navigation_bar" /> 
     
 
  <com.example.meituandemo.MyScrollView 
    android:id="@+id/scrollView" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" > 
 
    <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:orientation="vertical" > 
 
      <ImageView 
        android:id="@+id/iamge" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:background="@drawable/pic" 
        android:scaleType="centerCrop" /> 
 
      <include 
        android:id="@+id/buy" 
        layout="@layout/buy_layout" /> 
 
      <ImageView 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:background="@drawable/one" 
        android:scaleType="centerCrop" /> 
 
      <ImageView 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:background="@drawable/one" 
        android:scaleType="centerCrop" /> 
 
      <ImageView 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:background="@drawable/one" 
        android:scaleType="centerCrop" /> 
    </LinearLayout> 
  </com.example.meituandemo.MyScrollView> 
 
</LinearLayout> 

package com.example.meituandemo; 
 
import android.content.Context; 
import android.os.Handler; 
import android.util.AttributeSet; 
import android.view.MotionEvent; 
import android.widget.ScrollView; 
/** 
 * 博客地址:http://blog.csdn.net/xiaanming 
 * 
 * @author xiaanming 
 * 
 */ 
public class MyScrollView extends ScrollView { 
  private OnScrollListener onScrollListener; 
  /** 
   * 主要是用在用戶手指離開MyScrollView，MyScrollView還在繼續(xù)滑動，我們用來保存Y的距離，然后做比較 
   */ 
  private int lastScrollY; 
   
  public MyScrollView(Context context) { 
    this(context, null); 
  } 
   
  public MyScrollView(Context context, AttributeSet attrs) { 
    this(context, attrs, 0); 
  } 
 
  public MyScrollView(Context context, AttributeSet attrs, int defStyle) { 
    super(context, attrs, defStyle); 
  } 
   
  /** 
   * 設(shè)置滾動接口 
   * @param onScrollListener 
   */ 
  public void setOnScrollListener(OnScrollListener onScrollListener) { 
    this.onScrollListener = onScrollListener; 
  } 
 
 
  /** 
   * 用于用戶手指離開MyScrollView的時候獲取MyScrollView滾動的Y距離，然后回調(diào)給onScroll方法中 
   */ 
  private Handler handler = new Handler() { 
 
    public void handleMessage(android.os.Message msg) { 
      int scrollY = MyScrollView.this.getScrollY(); 
       
      //此時的距離和記錄下的距離不相等，在隔5毫秒給handler發(fā)送消息 
      if(lastScrollY != scrollY){ 
        lastScrollY = scrollY; 
        handler.sendMessageDelayed(handler.obtainMessage(), 5);  
      } 
      if(onScrollListener != null){ 
        onScrollListener.onScroll(scrollY); 
      } 
       
    }; 
 
  };  
 
  /** 
   * 重寫onTouchEvent， 當(dāng)用戶的手在MyScrollView上面的時候， 
   * 直接將MyScrollView滑動的Y方向距離回調(diào)給onScroll方法中，當(dāng)用戶抬起手的時候， 
   * MyScrollView可能還在滑動，所以當(dāng)用戶抬起手我們隔5毫秒給handler發(fā)送消息，在handler處理 
   * MyScrollView滑動的距離 
   */ 
  @Override 
  public boolean onTouchEvent(MotionEvent ev) { 
    if(onScrollListener != null){ 
      onScrollListener.onScroll(lastScrollY = this.getScrollY()); 
    } 
    switch(ev.getAction()){ 
    case MotionEvent.ACTION_UP: 
       handler.sendMessageDelayed(handler.obtainMessage(), 5);  
      break; 
    } 
    return super.onTouchEvent(ev); 
  } 
 
 
  /** 
   * 
   * 滾動的回調(diào)接口 
   * 
   * @author xiaanming 
   * 
   */ 
  public interface OnScrollListener{ 
    /** 
     * 回調(diào)方法， 返回MyScrollView滑動的Y方向距離 
     * @param scrollY 
     *       、 
     */ 
    public void onScroll(int scrollY); 
  } 
   
   
 
} 

package com.example.meituandemo; 
 
import android.app.Activity; 
import android.content.Context; 
import android.graphics.PixelFormat; 
import android.os.Bundle; 
import android.view.Gravity; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.WindowManager; 
import android.view.WindowManager.LayoutParams; 
import android.widget.LinearLayout; 
import com.example.meituandemo.MyScrollView.OnScrollListener; 
/** 
 * 博客地址:http://blog.csdn.net/xiaanming 
 * 
 * @author xiaanming 
 * 
 */ 
public class MainActivity extends Activity implements OnScrollListener{ 
  private MyScrollView myScrollView; 
  private LinearLayout mBuyLayout; 
  private WindowManager mWindowManager; 
  /** 
   * 手機(jī)屏幕寬度 
   */ 
  private int screenWidth; 
  /** 
   * 懸浮框View 
   */ 
  private static View suspendView; 
  /** 
   * 懸浮框的參數(shù) 
   */ 
  private static WindowManager.LayoutParams suspendLayoutParams; 
  /** 
   * 購買布局的高度 
   */ 
  private int buyLayoutHeight; 
  /** 
   * myScrollView與其父類布局的頂部距離 
   */ 
  private int myScrollViewTop; 
 
  /** 
   * 購買布局與其父類布局的頂部距離 
   */ 
  private int buyLayoutTop; 
   
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
     
    myScrollView = (MyScrollView) findViewById(R.id.scrollView); 
    mBuyLayout = (LinearLayout) findViewById(R.id.buy); 
     
    myScrollView.setOnScrollListener(this); 
    mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE); 
    screenWidth = mWindowManager.getDefaultDisplay().getWidth();  
  } 
 
  /** 
   * 窗口有焦點(diǎn)的時候，即所有的布局繪制完畢的時候，我們來獲取購買布局的高度和myScrollView距離父類布局的頂部位置 
   */ 
  @Override  
  public void onWindowFocusChanged(boolean hasFocus) {  
    super.onWindowFocusChanged(hasFocus);  
    if(hasFocus){ 
      buyLayoutHeight = mBuyLayout.getHeight(); 
      buyLayoutTop = mBuyLayout.getTop(); 
       
      myScrollViewTop = myScrollView.getTop(); 
    } 
  }  
 
 
 
  /** 
   * 滾動的回調(diào)方法，當(dāng)滾動的Y距離大于或者等于 購買布局距離父類布局頂部的位置，就顯示購買的懸浮框 
   * 當(dāng)滾動的Y的距離小于 購買布局距離父類布局頂部的位置加上購買布局的高度就移除購買的懸浮框 
   * 
   */ 
  @Override 
  public void onScroll(int scrollY) { 
    if(scrollY >= buyLayoutTop){ 
      if(suspendView == null){ 
        showSuspend(); 
      } 
    }else if(scrollY <= buyLayoutTop + buyLayoutHeight){ 
      if(suspendView != null){ 
        removeSuspend(); 
      } 
    } 
  } 
 
 
  /** 
   * 顯示購買的懸浮框 
   */ 
  private void showSuspend(){ 
    if(suspendView == null){ 
      suspendView = LayoutInflater.from(this).inflate(R.layout.buy_layout, null); 
      if(suspendLayoutParams == null){ 
        suspendLayoutParams = new LayoutParams(); 
        suspendLayoutParams.type = LayoutParams.TYPE_PHONE; //懸浮窗的類型，一般設(shè)為2002，表示在所有應(yīng)用程序之上，但在狀態(tài)欄之下  
        suspendLayoutParams.format = PixelFormat.RGBA_8888;  
        suspendLayoutParams.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL  
             | LayoutParams.FLAG_NOT_FOCUSABLE; //懸浮窗的行為，比如說不可聚焦，非模態(tài)對話框等等  
        suspendLayoutParams.gravity = Gravity.TOP; //懸浮窗的對齊方式 
        suspendLayoutParams.width = screenWidth; 
        suspendLayoutParams.height = buyLayoutHeight;  
        suspendLayoutParams.x = 0; //懸浮窗X的位置 
        suspendLayoutParams.y = myScrollViewTop; ////懸浮窗Y的位置 
      } 
    } 
     
    mWindowManager.addView(suspendView, suspendLayoutParams); 
  } 
   
   
  /** 
   * 移除購買的懸浮框 
   */ 
  private void removeSuspend(){ 
    if(suspendView != null){ 
      mWindowManager.removeView(suspendView); 
      suspendView = null; 
    } 
  } 
 
}