我正在使用 Swing 用 Java 编写一个程序,并使用包含箭头键的 GUI。方向键与键盘上的方向键相对应。
当我按下键盘上的向上箭头键时,我希望 GUI 上的向上箭头键显示为被按下。在我释放箭头键之前,它应该显示它仍在被按下,并且当释放时它也应该释放。
到目前为止我的代码片段(仅适用于向上按钮),我认为这在显示被按下类别中是完全错误的:
...
if (e.getKeyCode() == KeyEvent.VK_UP) {
actionArrowUp();
JButton buttonUp = (JButton) mainTab.getComponent(4);
buttonUp.setSelected(true);
}
...
@Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_UP)
actionArrowUpRelease();
buttonUp.setSelected(true);
使用 keyBindings (正如 @trashgod 已经提到的)是the要走的路。获得与通过空格/输入激活按钮完全相同的视觉行为(当它获得焦点时)
- 实现委托给为按下/释放注册的按钮默认操作的操作
- 需要绑定到按键的按下和释放来模拟
- 将绑定安装到 WHEN_ANCESTOR 类型的 inputMap 中按钮的父级
In code:
// the delegating action
public static class SimulateButtonAction extends AbstractAction {
AbstractButton button;
public SimulateButtonAction(AbstractButton model, String fire) {
super(fire);
this.button = model;
}
@Override
public void actionPerformed(ActionEvent e) {
Action delegate = button.getActionMap().get(getName());
delegate.actionPerformed(new ActionEvent(button,
ActionEvent.ACTION_PERFORMED, getName()));
}
public String getName() {
return (String) getValue(Action.NAME);
}
}
// example usage
JComponent content = new JPanel(new GridLayout(0, 5));
Action log = new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("triggered: " + ((AbstractButton) e.getSource()).getText());
}
};
String pressed = "pressed";
String released = "released";
ActionMap actionMap = content.getActionMap();
InputMap inputMap = content.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
String[] arrows = {"UP", "DOWN", "LEFT", "RIGHT"};
for (int i = 0; i < arrows.length; i++) {
JButton button = new JButton(log);
button.setAction(log);
button.setText(arrows[i]);
content.add(button);
// simulate pressed
String pressedKey = pressed + arrows[i];
inputMap.put(KeyStroke.getKeyStroke(arrows[i]), pressedKey);
actionMap.put(pressedKey, new SimulateButtonAction(button, pressed));
String releasedKey = released + arrows[i];
inputMap.put(KeyStroke.getKeyStroke(released + " " +arrows[i]), releasedKey);
actionMap.put(releasedKey, new SimulateButtonAction(button, released));
}
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)