Question

我一直在尝试使用箭头键作为我的应用程序的一部分。按照最佳实践，我坚持使用键绑定。我发现arow键不会产生键入事件，所以我使用了这个answer。

但是，我的应用程序有许多组件，我发现如果我的JFrame中有一个JToolbar，则前一个链接中的方法不再有效。为什么这样，我如何使用JToolbar并使用键绑定？

这是SSCCE

public class ArrowTest extends JFrame {

    public static void main(final String[] args){
        final ArrowTest at = new ArrowTest();
        at.setSize(100,200);

        final JPanel jp = new JPanel();
        jp.setBackground(Color.BLUE);
        at.getContentPane().add(jp);
        final JToolBar toolbar = new JToolBar();
        toolbar.add(new JButton());
        //at.add(toolbar);
        at.setVisible(true);
    }

    public ArrowTest() {
        super();    
        this.getContentPane().setLayout(new GridBagLayout());    
        this.getContentPane().setBackground(Color.BLACK);    
        this.setKeyBindings();
    }

    public void setKeyBindings() {

        final int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;    
        final ActionMap actionMap = this.getRootPane().getActionMap();
        final InputMap inputMap = this.getRootPane().getInputMap(condition);

        for (final Direction direction : Direction.values()) {
            inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_V,0), direction.getText());
            inputMap.put(direction.getKeyStroke(), direction.getText());
            actionMap.put(direction.getText(), new MyArrowBinding(direction.getText()));
        }

    }

    enum Direction {
        UP("Up", KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0)),
        DOWN("Down", KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0)),
        LEFT("Left", KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0)),
        RIGHT("Right", KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0));

        Direction(final String text, final KeyStroke keyStroke) {
            this.text = text;
            this.keyStroke = keyStroke;
        }
        private String text;
        private KeyStroke keyStroke;

        public String getText() {
            return text;
        }

        public KeyStroke getKeyStroke() {
            return keyStroke;
        }

        @Override
        public String toString() {
            return text;
        }
    }

    private class MyArrowBinding extends AbstractAction {

        private static final long serialVersionUID = -6904517741228319299L;

        public MyArrowBinding(final String text) {
            super(text);
            putValue(ACTION_COMMAND_KEY, text);
        }

        @Override
        public void actionPerformed(final ActionEvent e) {
            final String actionCommand = e.getActionCommand();
            System.out.println("Key Binding: " + actionCommand);
        }
    }    
}

Answer 1

默认情况下，JToolBar会为KeyStroke的向上/向下/向左/向右注册一个动作，而您添加到JToolBar的{{1}}会自动抓取焦点，因此您不会绑定到rootpane时会看到任何内容（工具栏会在你之前捕获事件）。

一种解决方案是让JFrame和JToolBar无法集中，让您的JButton可以集中精力（实际上您可以离开JPanel和{{1请求专注于您的面板，但这也意味着您必须处理面板的焦点管理）：

JToolBar

我也通过拨打JButton

来取代您对

import java.awt.Color;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;

import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.KeyStroke;

public class ArrowTest extends JFrame {

    public static void main(final String[] args) {
        final ArrowTest at = new ArrowTest();
        at.setSize(100, 200);

        final JPanel jp = new JPanel();
        jp.setBackground(Color.BLUE);
        jp.setFocusable(true);
        at.getContentPane().add(jp);
        final JToolBar toolbar = new JToolBar();
        JButton comp = new JButton();
        toolbar.add(comp);
        at.add(toolbar);
        at.setVisible(true);
    }

    public ArrowTest() {
        super();
        this.getContentPane().setLayout(new GridBagLayout());
        this.getContentPane().setBackground(Color.BLACK);
        this.setKeyBindings();
    }

    public void setKeyBindings() {
        for (final Direction direction : Direction.values()) {
            MyArrowBinding binding = new MyArrowBinding(direction.getText());
            getRootPane().registerKeyboardAction(binding, direction.getText(), direction.getKeyStroke(),
                    JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        }
    }

    enum Direction {
        UP("Up", KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0)), DOWN("Down", KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0)), LEFT("Left",
                KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0)), RIGHT("Right", KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0));

        Direction(final String text, final KeyStroke keyStroke) {
            this.text = text;
            this.keyStroke = keyStroke;
        }

        private String text;
        private KeyStroke keyStroke;

        public String getText() {
            return text;
        }

        public KeyStroke getKeyStroke() {
            return keyStroke;
        }

        @Override
        public String toString() {
            return text;
        }
    }

    private class MyArrowBinding extends AbstractAction {

        private static final long serialVersionUID = -6904517741228319299L;

        public MyArrowBinding(final String text) {
            super(text);
            putValue(ACTION_COMMAND_KEY, text);
        }

        @Override
        public void actionPerformed(final ActionEvent e) {
            final String actionCommand = e.getActionCommand();
            System.out.println("Key Binding: " + actionCommand);
        }
    }
}

的来电

Answer 2

按照answer中的建议，我使用

解决了这个问题

public void setKeyBindings() {

    final int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;    
    final ActionMap actionMap = this.getRootPane().getActionMap();
    final InputMap inputMap = this.getRootPane().getInputMap(condition);

    for (final Direction direction : Direction.values()) {
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_V,0), direction.getText());
        inputMap.put(direction.getKeyStroke(), direction.getText());
        actionMap.put(direction.getText(), new MyArrowBinding(direction.getText()));
    }

    condition = JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT;

    actionMap = toolbar.getActionMap();
    inputMap = toolbar.getInputMap(condition);


    for (final Direction direction : Direction.values()) {
        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_V,0), direction.getText());
        inputMap.put(direction.getKeyStroke(), direction.getText());
        actionMap.put(direction.getText(), new MyArrowBinding(direction.getText()));
    } 


}

为什么Jtoolbar会破坏我的keyBindings？

2 个答案: