Java - 如何防止WindowClosing實際關閉窗口

Question

我似乎對大多數人都有相反的問題。我要看看下面的非常標準的代碼，如果用戶想要關閉該窗口之前做一些節省：

frame.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE); 
    frame.addWindowListener(new WindowAdapter() { 
    public void windowClosing(WindowEvent ev) { 
     boolean close = true; 
     // check some files, asking if the user wants to save 
     // YES and NO handle OK, but if the user hits Cancel on any file, 
     // I want to abort the close process  
     // So if any of them hit Cancel, I set "close" to false 
     if (close) { 
      frame.dispose(); 
      System.exit(0); 
     } 
     }    
}); 

無論我怎麼努力，當我走出來的windowClosing的窗口始終關閉。將WindowAdapter更改爲WindowListener沒有任何區別。奇怪的是，文檔中明確提到「如果程序在處理這個事件時沒有明確隱藏或者處理窗口，那麼窗口關閉操作將被取消」，但是這對我來說並不是那樣。有沒有其他的方式來處理框架上的x？ TIA

Answer 1

我只是嘗試這樣做最小的測試案例：

import java.awt.event.WindowAdapter; 
import java.awt.event.WindowEvent; 

import javax.swing.JFrame; 
import javax.swing.WindowConstants; 

public class test { 

    public static void main(String[] args) { 
     final JFrame frame = new JFrame("Test"); 
     frame.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE); 
     frame.addWindowListener(new WindowAdapter() { 
      public void windowClosing(WindowEvent ev) { 
       //frame.dispose(); 
      } 
     }); 
     frame.setVisible(true); 

    } 

} 

如果我保持通話處置評論，並點擊關閉按鈕，窗口不會退出。取消註釋並點擊關閉按鈕，窗口關閉。

我不得不猜測在你的邏輯中設置你的「關閉」變量有問題。嘗試雙重檢查。

Answer 2

這是關鍵，methinks：frame.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);使我在製作的測試用例中有所不同。

Answer 3

不知道從哪裏是你的問題，

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 

public class ClosingFrame extends JFrame { 

    private JMenuBar MenuBar = new JMenuBar(); 
    private JFrame frame = new JFrame(); 
    private static final long serialVersionUID = 1L; 
    private JMenu File = new JMenu("File"); 
    private JMenuItem Exit = new JMenuItem("Exit"); 

    public ClosingFrame() { 
     File.add(Exit); 
     MenuBar.add(File); 
     Exit.addActionListener(new ExitListener()); 
     WindowListener exitListener = new WindowAdapter() { 

      @Override 
      public void windowClosing(WindowEvent e) { 
       int confirm = JOptionPane.showOptionDialog(frame, 
         "Are You Sure to Close this Application?", 
         "Exit Confirmation", JOptionPane.YES_NO_OPTION, 
         JOptionPane.QUESTION_MESSAGE, null, null, null); 
       if (confirm == JOptionPane.YES_OPTION) { 
        System.exit(1); 
       } 
      } 
     }; 
     frame.addWindowListener(exitListener); 
     frame.setDefaultCloseOperation(EXIT_ON_CLOSE); 
     frame.setJMenuBar(MenuBar); 
     frame.setPreferredSize(new Dimension(400, 300)); 
     frame.setLocation(100, 100); 
     frame.pack(); 
     frame.setVisible(true); 
    } 

    private class ExitListener implements ActionListener { 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      int confirm = JOptionPane.showOptionDialog(frame, 
        "Are You Sure to Close this Application?", 
        "Exit Confirmation", JOptionPane.YES_NO_OPTION, 
        JOptionPane.QUESTION_MESSAGE, null, null, null); 
      if (confirm == JOptionPane.YES_OPTION) { 
       System.exit(1); 
      } 
     } 
    } 

    public static void main(String[] args) { 
     SwingUtilities.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       ClosingFrame cf = new ClosingFrame(); 
      } 
     }); 
    } 
} 

Answer 4

對於這件事的處理做：
如果用戶選擇是，然後使用setDefaultCloseOperation(DISPOSE_ON_CLOSE);的是if else

大括號內如果取消然後使用setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);

考慮實例：

int safe = JOptionPane.showConfirmDialog(null, "titleDetails!", "title!!", JOptionPane.YES_NO_CANCEL_OPTION); 

if(safe == JOptionPane.YES_OPTION){ 
    setDefaultCloseOperation(DISPOSE_ON_CLOSE);//yes 

} else if (safe == JOptionPane.CANCEL_OPTION) { 
    setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);//cancel 
} else { 
    setDefaultCloseOperation(DISPOSE_ON_CLOSE);//no 
} 

Answer 5

不知道你的問題在哪裏，但這對我有用！

frame.addWindowListener（新WindowAdapter的（）{

 public void windowClosing(WindowEvent evt){ 
         int res=JOptionPane.showConfirmDialog(null, 
           "Do you want to exit.?"); 
         if(res==JOptionPane.YES_OPTION){ 
           Cal.this.dispose(); 
         } 
     }        
    }); 

Answer 6

爲了解決我想這篇文章的第一個答案。 作爲單獨的應用程序它的工作原理相同的問題，但不是在我的情況。 也許不同的是在JFrame中（回答）和FrameView（我的情況）。

public class MyApp extends SingleFrameApplication { // application class of my project 
    ... 
    protected static MyView mainForm; // main form of application 
    ... 
} 
public class MyView extends FrameView { 
    ... 
    //Adding this listener solves the problem. 
    MyApp.getInstance().addExitListener(new ExitListener() { 

     @Override 
     public boolean canExit(EventObject event) { 
     boolean res = false; 
     int reply = JOptionPane.showConfirmDialog(null, 
       "Are You sure?", "", JOptionPane.YES_NO_OPTION); 
     if (reply == JOptionPane.YES_OPTION) { 
      res = true; 
     } 
     return res; 
     } 
     @Override 
     public void willExit(EventObject event) { 
     } 
    }); 
    ... 
} 

Answer 7

setDefaultCloseOperation（）方法幫助的問題。https://chortle.ccsu.edu/java5/Notes/chap56/ch56_9.html

查看此連結