例如淘寶，京東之類的點擊購買之后，就會出現一個PopupWindow的窗口從下面彈出來，以便顧客更好的體驗和方便顧客的操作性。

![(P%EK9J)U[9%(G$ES6`T}W.png

顯示popupWindow 
private void showPopwindow() {    
     // 1 利用layoutInflater獲得View    
    LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);    
    View view = inflater.inflate(R.layout.popupwindow_add_product, null);    
    // 2下面是兩種方法得到寬度和高度 getWindow().getDecorView().getWidth()
     final PopupWindow window = new PopupWindow(view,WindowManager.LayoutParams.MATCH_PARENT,WindowManager.LayoutParams.WRAP_CONTENT);
     // 3 參數設置// 設置popWindow彈出窗體可點擊，這句話必須添加，并且是true
window.setFocusable(true);
    // 實例化一個ColorDrawable顏色為半透明
   ColorDrawable dw = new ColorDrawable(0xFFFFFFFF);
   window.setBackgroundDrawable(dw);
   // 設置popWindow的顯示和消失動畫
    window.setAnimationStyle(R.style.mypopwindow_anim_style);
   // 4 控件處理
   ImageView iv_goodinfo_photo = (ImageView) view.findViewById(R.id.iv_goodinfo_photo);
   TextView tv_goodinfo_name = (TextView) view.findViewById(R.id.tv_goodinfo_name);
   TextView tv_goodinfo_price = (TextView) view.findViewById(R.id.tv_goodinfo_price);
   NumberAddSubView nas_goodinfo_num = (NumberAddSubView) view.findViewById(R.id.nas_goodinfo_num);
   Button bt_goodinfo_cancel = (Button) view.findViewById(R.id.bt_goodinfo_cancel);
   Button bt_goodinfo_confim = (Button) view.findViewById(R.id.bt_goodinfo_confim);
   // 加載圖片
   Glide.with(GoodsInfoActivity.this).load(Constants.Base_URl_IMAGE + goods_bean.getFigure()).into(iv_goodinfo_photo);
   // 名稱
   tv_goodinfo_name.setText(goods_bean.getName());
   // 顯示價格
   tv_goodinfo_price.setText(goods_bean.getCover_price());
   // 設置最大值和當前值
    nas_goodinfo_num.setMaxValue(5);
    nas_goodinfo_num.setValue(goods_bean.getNumber());
    //這是自定義view中接口的回調方法，以便能操作view視圖
    nas_goodinfo_num.setOnNumberChangeListener(new  NumberAddSubView.OnNumberChangeListener() { 
          @Override    public void addNumber(View view, int value) {      
          int number = goods_bean.getNumber();  
          goods_bean.setNumber(number + 1);     
          if (number + 1 >= 5) {    
          Toast.makeText(GoodsInfoActivity.this, "該商品最多購買5個",Toast.LENGTH_SHORT).show();    
          goods_bean.setNumber(5);       
        }  
  }   
          @Override    public void subNumner(View view, int value) {       
               int number = goods_bean.getNumber();   
               goods_bean.setNumber(number - 1);     
               if (number <= 1) {          
        Toast.makeText(GoodsInfoActivity.this, "該商品最少購買1個", Toast.LENGTH_SHORT).show();   
               goods_bean.setNumber(1);      
      }  
  }
});
     // 5 在底部顯示
       window.showAtLocation(GoodsInfoActivity.this.findViewById(R.id.ll_goods_root),       
Gravity.BOTTOM, 0, VirtualkeyboardHeight.getBottomStatusHeight(GoodsInfoActivity.this));