滾動問題與位圖圖像領域，黑莓

Question

有一個標籤字段，它下面有一個位圖字段和下方有一個列表字段

當我向下滾動所有重新繪製是好的，但當我從列表字段向上滾動到位圖字段

然後我的圖像不會重新繪製，直到我到達最頂部的標籤字段。

我無法弄清楚爲什麼會發生

標籤字段設置爲focussable因爲某些原因...

使得位圖字段focussable不也解決了問題

代碼：

LabelField lbl = new LabelField("Hello",Field.focussable) 

detail_img = Bitmap.getBitmapResource("container.png"); 
detail_img_field = new BitmapField(detail_img); 

reviewlist = new Review_List(my_vector); //Review_List is a class that fills value in list field 

reviewlistManager = new VerticalFieldManager(Manager.VERTICAL_SCROLL |Manager.VERTICAL_SCROLLBAR) 
{    

       protected void paint(net.rim.device.api.ui.Graphics graphics) 
        { 
         super.paint(graphics); 
        } 

         protected boolean keyDown(int keycode, int status) 
         { 
          my_Screen.this.invalidate(); 
          return super.keyDown(keycode, status); 
         } 
         protected boolean keyUp(int keycode, int time) 
         { 
          my_Screen.this.invalidate(); 
          return super.keyUp(keycode, time); 
         } 

         protected boolean navigationMovement(int dx, int dy, int status, int time) 
         { 
          my_Screen.this.invalidate(); 
          return super.navigationMovement(dx, dy, status, time); 
         } 

         protected int moveFocus(int amount, int status, int time) 
         { 
          my_Screen.this.invalidate(); 
          return super.moveFocus(amount, status, time); 
         } 
         protected void onFocus(int direction) 
         { 
          my_Screen.this.invalidate(); 
          super.onFocus(direction); 
         } 
         protected void onUnfocus() 
         { 
          my_Screen.this.invalidate(); 
          super.onUnfocus(); 
         } 

       }; 

reviewlistManager.add(reviewlist); 
backgroundMannager.add(reviewlistManager); 
add(backgroundMannager); 

Answer 1

yuppieeeeee

我得到的答案

我剛放置的位圖領域的VerticalFieldManager內，用垂直滾動啓用ñ我的問題得到有效解決......

代碼：

rest_manager = new VerticalFieldManager(Manager.VERTICAL_SCROLL) 
      { 
      protected void paint(net.rim.device.api.ui.Graphics graphics) 
      { 
        int y = this.getVerticalScroll();          
            graphics.drawBitmap(0, y, rank_img.getWidth()+10, 
rank_img.getHeight(), rank_img, 0, 0); 

            super.paint(graphics); 
           } 
        } 

Answer 2

這是模擬器還是真實設備？有時模擬器會出現渲染問題（比如不重繪應該有的區域），而真實設備則不會。