來自另一個JFrame的JTable值

Question

我有JTable ，我想從另一個框架的特定單元格設置值。 當我嘗試執行此操作時，出現空指針異常。 我更改了修飾符並刪除了異常，但仍然無法設置該值。

請大家幫忙

public ChequeVoucher(int id,int row){
       try {
           String str = get_bank_name(id);
           System.out.println(str); 

           table.getModel().setValueAt(str,row,5);
           table.getModel().setValueAt(id,row,4);
       } catch (SQLException f) {
       }
       setBank(id,row); 
    }

public void setBank(int id,int row){
    try {
            String str = get_bank_name(id);
            table.getModel().setValueAt(str,row,5);
        } catch (SQLException f) {
        }
    }

chequevoucher是我的構造函數，這段代碼很不錯，直到

 table.getModel().setValueAt(str,row,5);

我從中獲取值的JFrame是

   table.addMouseListener(new MouseAdapter() {
       public void mouseClicked(MouseEvent e) {
         int row = table.getSelectedRow();
         int col = table.getSelectedColumn();
         String str_id = (String)GetID(row,0); 
         int id = Integer.parseInt(str_id);
         ChequeVoucher CV = new ChequeVoucher(id,row); 
         setVisible(false);
        }
     });

訪問修飾符不是靜態的，因此出現以下錯誤堆棧

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException 
at client.ChequeVoucher.(ChequeVoucher.java:215) 
at client.popupBanks$3.mouseClicked(popupBanks.java:130) 
at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:253) 
at java.awt.Component.processMouseEvent(Component.java:6292) 
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267) 
at java.awt.Component.processEvent(Component.java:6054) 
at java.awt.Container.processEvent(Container.java:2041) 
at java.awt.Component.dispatchEventImpl(Component.java:4652) 
at java.awt.Container.dispatchEventImpl(Container.java:2099) 
at java.awt.Component.dispatchEvent(Component.java:4482) 
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577) 
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4247) 
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168) 
at java.awt.Container.dispatchEventImpl(Container.java:2085) 
at java.awt.Window.dispatchEventImpl(Window.java:2478) 
at java.awt.Component.dispatchEvent(Component.java:4482) 
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:644) 
at java.awt.EventQueue.access$000(EventQueue.java:85) 
at java.awt.EventQueue$1.run(EventQueue.java:603) 
at java.awt.EventQueue$1.run(EventQueue.java:601) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87) 
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98) 
at java.awt.EventQueue$2.run(EventQueue.java:617) 
at java.awt.EventQueue$2.run(EventQueue.java:615) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87) 
at java.awt.EventQueue.dispatchEvent(EventQueue.java:614) 
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) 
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) 
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) 
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) 
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) 
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

當我將修飾符設為靜態時，我沒有異常，但是什么也沒有發生，而且我再也JTable了

 case KeyEvent.VK_F5:
     switch(col){
         case 4:
         //show the banks 
         popupBanks pB = new popupBanks(row); 
         pB.setVisible(true);

         break;
  }

對不起，以前的帖子不清楚

Answer 1

您調用的ChequeVoucher方法絕對是一個構造函數，並且在這一點上，您的表為null，除非您用其他方式指定其值。 您可以在構造函數中添加表，以解決該問題。 最好的解決方案是使用JTable作為構造函數參數創建ChequeVoucher並使用方法進行其他操作。