I have a JFileChooser in a JFrame. I've added an ActionListener to the JFileChooser so that the "Cancel" button works when clicked. I can also tab to the "Cancel" button, but when I then hit the "Enter" key, nothing happens (i.e., the ActionListener isn't called with the event command JFileChooser.CANCEL_SELECTION). What must I do with the JFileChooser so that hitting the "Enter" key when on the "Cancel" button is equivalent to clicking on the "Cancel" button?

這是我看到的(錯誤)行為的一個簡單示例:

Here's a simple example of the (mis)behavior I'm seeing:

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFileChooser;
import javax.swing.JFrame;

public final class TestApp {
    public static void main(final String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                try {
                    final JFileChooser chooser = new JFileChooser();
                    chooser.addActionListener(new ActionListener() {
                        public void actionPerformed(final ActionEvent e) {
                            System.exit(0);
                        }
                    });
                    final JFrame frame = new JFrame();
                    frame.add(chooser);
                    frame.pack();
                    frame.setVisible(true);
                }
                catch (final Throwable t) {
                    t.printStackTrace();
                }
            }
        });
    }
}

要查看(錯誤)行為，請執行程序，使用 Tab 鍵選擇取消"，然后按Enter"鍵.該程序不會在我的平臺上終止——盡管當我單擊取消"按鈕時它會終止.

To see the (mis)behavior, execute the program, tab to "Cancel", and then hit the "Enter" key. The program doesn't terminate on my platform -- although it does when I click on the "Cancel" button.

擴展 JFileChooser 和覆蓋 cancelSelection() 也不起作用(顯然，當在取消"按鈕).

Extending JFileChooser and overriding cancelSelection() also doesn't work (apparently, that function isn't called when the "Enter" key is hit while on the "Cancel" button).

(錯誤)行為發生在我的 Fedora 10 x86_64 系統上，使用 Java 5、6 和 7.

The (mis)behavior occurs on my Fedora 10 x86_64 system with Java 5, 6, and 7.

ADDENDUM:以下將 KeyEventPostProcessor 添加到當前 KeyboardFocusManager 并且似乎可以執行我想要的操作:

ADDENDUM: The following adds a KeyEventPostProcessor to the current KeyboardFocusManager and appears to do what I want:

import java.awt.Component;
import java.awt.KeyEventPostProcessor;
import java.awt.KeyboardFocusManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;

public final class TestApp {
    public static void main(final String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                try {
                    final JFileChooser chooser = new JFileChooser();
                    chooser.addActionListener(new ActionListener() {
                        public void actionPerformed(final ActionEvent e) {
                            System.out.println(e.paramString());
                            System.exit(0);
                        }
                    });
                    final KeyboardFocusManager kfm = KeyboardFocusManager
                            .getCurrentKeyboardFocusManager();
                    kfm.addKeyEventPostProcessor(new KeyEventPostProcessor() {
                        @Override
                        public boolean postProcessKeyEvent(final KeyEvent e) {
                            if (e.getID() == KeyEvent.KEY_RELEASED
                                    && e.getKeyCode() == KeyEvent.VK_ENTER) {
                                final Component comp = e.getComponent();
                                if (chooser.isAncestorOf(comp)) {
                                    if (!(comp instanceof JButton)) {
                                        chooser.approveSelection();
                                    }
                                    else {
                                        final JButton button = (JButton) comp;
                                        if ("Cancel".equals(button.getText())) {
                                            chooser.cancelSelection();
                                        }
                                        else {
                                            chooser.approveSelection();
                                        }
                                    }
                                }
                            }
                            return false;
                        }
                    });
                    final JFrame frame = new JFrame();
                    frame.add(chooser);
                    frame.pack();
                    frame.setVisible(true);
                }
                catch (final Throwable t) {
                    t.printStackTrace();
                }
            }
        });
    }
}

然而，這似乎需要做很多工作，只是為了能夠區分按下取消"按鈕上的回車鍵和其他任何地方.

It seems like a lot of work, however, just to be able to distinguish between hitting the enter key on the "Cancel" button versus anywhere else.

你覺得它有什么問題嗎?

Do you see any problems with it?

發現的解決方案:將 GUI 外觀設置為我的系統 (Linux) 的本機外觀和感覺可以滿足我的需求，而無需其他任何東西.這是我所不知道的，也是我一直在尋找的.解決方案是有以下

DISCOVERED SOLUTION: Setting the GUI Look and Feel to the native one for my system (Linux) does what I want without the need for anything else. This is what I was ignorant of and what I was looking for. The solution is to have the following

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

作為 main() 方法的第一個可執行語句.然后可以省去所有焦點偵聽器、關鍵事件處理器等.

as the first executable statement of the main() method. One can then dispense with all focus listeners, key event processors, etc.

我已將 100 分獎勵給最有幫助的受訪者.

I've awarded the 100 points to the most helpful respondent.

推薦答案

程序不會在我的平臺上終止.

The program doesn't terminate on my platform.