使用 Tab 键从 JTextArea 移动焦点 [英] Moving focus from JTextArea using tab key

问题描述

如前所述，我想更改 JTextArea 中的默认 TAB 行为(使其像 JTextField 或类似组件一样)

As stated, I want to change the default TAB behaviour within a JTextArea (so that it acts like a JTextField or similar component)

这是事件操作

private void diagInputKeyPressed(java.awt.event.KeyEvent evt) {
    if(evt.KEY_PRESSED == java.awt.event.KeyEvent.VK_TAB) {
        actionInput.transferFocus();
    }
}

这里是听众

diagInput.addKeyListener(new java.awt.event.KeyAdapter() {
    public void keyPressed(java.awt.event.KeyEvent evt) {
        diagInputKeyPressed(evt);
    }
});

我也尝试过 evt.KEY_TYPED 并没有任何乐趣.

I've tried evt.KEY_TYPED as well with no joy.

有什么想法吗?

快速我也试过 requestFocus() 代替 transferFocus()

quick edit: I've also tried requestFocus() in place of transferFocus()

推荐答案

根据 这个类:

/**
 * Some components treat tabulator (TAB key) in their own way.
 * Sometimes the tabulator is supposed to simply transfer the focus
 * to the next focusable component.
 * <br/>
 * Here s how to use this class to override the "component's default"
 * behavior:
 * <pre>
 * JTextArea  area  = new JTextArea(..);
 * <b>TransferFocus.patch( area );</b>
 * </pre>
 * This should do the trick. 
 * This time the KeyStrokes are used.
 * More elegant solution than TabTransfersFocus().
 * 
 * @author kaimu
 * @since 2006-05-14
 * @version 1.0
 */
public class TransferFocus {

    /**
     * Patch the behaviour of a component. 
     * TAB transfers focus to the next focusable component,
     * SHIFT+TAB transfers focus to the previous focusable component.
     * 
     * @param c The component to be patched.
     */
    public static void patch(Component c) {
        Set<KeyStroke> 
        strokes = new HashSet<KeyStroke>(Arrays.asList(KeyStroke.getKeyStroke("pressed TAB")));
        c.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, strokes);
        strokes = new HashSet<KeyStroke>(Arrays.asList(KeyStroke.getKeyStroke("shift pressed TAB")));
        c.setFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, strokes);
    }
}

请注意，patch() 可以更短，根据 Joshua Goldberg在评论中，因为目标是获得返回由 JTextArea 覆盖的默认行为:

Note that patch() can be even shorter, according to Joshua Goldberg in the comments, since the goal is to get back default behaviors overridden by JTextArea:

component.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERS‌​AL_KEYS, null);
component.setFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERS‌​AL_KEYS, null);

这用于问题如何修改 JTextArea 中 Tab 键的行为?"

This is used in question "How can I modify the behavior of the tab key in a JTextArea?"

之前的实现确实涉及一个Listener 和一个 transferFocus():

The previous implementation involved indeed a Listener, and the a transferFocus():

   /**
     * Override the behaviour so that TAB key transfers the focus
     * to the next focusable component.
     */
    @Override
    public void keyPressed(KeyEvent e) {
        if(e.getKeyCode() == KeyEvent.VK_TAB) {
            System.out.println(e.getModifiers());
            if(e.getModifiers() > 0) a.transferFocusBackward();
            else a.transferFocus(); 
            e.consume();
        }
    }

e.consume(); 可能是你错过的，让它在你的情况下工作.

e.consume(); might have been what you missed to make it work in your case.

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