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使用tab键从JTextArea移动焦点

netbeans swing java

Tag · 技术社区 · 16 年前

如前所述,我想在 JTextArea (这样它的行为就像 JTextField 或类似组件)

这是活动动作

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

这是听众

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

我也试过evt.KEY_TYPED,但毫无乐趣。

有什么想法吗?

快速编辑:我也试过 requestFocus() 代替 transferFocus()

1 回复 | 直到 13 年前

Community Mohan Dere 8 年前

根据 this class :

/**
 * 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);
    }
}

注意 patch() 可以更短,根据 Joshua Goldberg 在……里面 the comments ,因为目标是恢复被覆盖的默认行为 JTextArea :

component.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSââAL_KEYS, null);
component.setFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSââAL_KEYS, null);

这是有疑问的“ How can I modify the behavior of the tab key in a JTextArea ? "

这个 previous implementation 确实涉及a Listener 和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(); 这可能是你错过的,让它在你的情况下发挥作用。