Java Keybindings

我需要绑定所有箭头键来执行相同的function，但每次都按下哪个键。 目前我只有在通过以下方式按下右箭头键时才有

DoneImg.getInputMap(JLabel.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "UpArrow"); Action MvRight = new AbstractAction() { public void actionPerformed(ActionEvent e) { //Do whatever here } }; DoneImg.getActionMap().put("RightArrow", MvRight); 

但我需要类似的东西

 DoneImg.getInputMap(JLabel.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), "RightArrow"); DoneImg.getInputMap(JLabel.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), "LeftArrow"); DoneImg.getInputMap(JLabel.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0), "DownArrow"); DoneImg.getInputMap(JLabel.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "UpArrow"); Action MvAll = new AbstractAction() { public void actionPerformed(ActionEvent e) { if (e.keypressed == "LeftArrow") {System.out.println("The left arrow was pressed!");} if (e.keypressed == "RightArrow") {System.out.println("The right arrow was pressed!");} //and so forth } }; DoneImg.getActionMap().put("RightArrow", MvAll); DoneImg.getActionMap().put("LeftArrow", MvAll); DoneImg.getActionMap().put("UpArrow", MvAll); DoneImg.getActionMap().put("DownArrow", MvAll); 

Answer 1

您所要求的实际上是反直觉的，并且违背了键绑定API的设计。

目的是为每个击键提供单个工作单元。 在我看来，这意味着你应该对每个箭头键分别采取行动。

它使得更容易遵循逻辑，进行更改，根据需要规避操作。

但我该说谁是对的：P

如果你看不到它的方法，一种方法很简单，就是为每个动作分配一个“命令”，然后你可以在触发actionPerformed时查询它。

 public TestKeyBindings02() { JPanel panel = new JPanel(); InputMap im = panel.getInputMap(JPanel.WHEN_IN_FOCUSED_WINDOW); ActionMap am = panel.getActionMap(); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), "RightArrow"); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), "LeftArrow"); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "UpArrow"); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0), "DownArrow"); am.put("RightArrow", new ArrowAction("RightArrow")); am.put("LeftArrow", new ArrowAction("LeftArrow")); am.put("UpArrow", new ArrowAction("UpArrow")); am.put("DownArrow", new ArrowAction("DownArrow")); } public class ArrowAction extends AbstractAction { private String cmd; public ArrowAction(String cmd) { this.cmd = cmd; } @Override public void actionPerformed(ActionEvent e) { if (cmd.equalsIgnoreCase("LeftArrow")) { System.out.println("The left arrow was pressed!"); } else if (cmd.equalsIgnoreCase("RightArrow")) { System.out.println("The right arrow was pressed!"); } else if (cmd.equalsIgnoreCase("UpArrow")) { System.out.println("The up arrow was pressed!"); } else if (cmd.equalsIgnoreCase("DownArrow")) { System.out.println("The down arrow was pressed!"); } } } 

Answer 2

您无权访问导致执行Action的KeyStroke。 因此，您需要创建4个动作并将参数传递给Action。 就像是：

 class SomeAction extends AbstractAction { public SomeAction(String name) { putValue(Action.NAME, name); putValue(ACTION_COMMAND_KEY, "Command: " + name); } public void actionPerformed(ActionEvent e) { System.out.println("Name: " + getValue(Action.NAME) ); System.out.println(e.getActionCommand()); } } 

您将Action添加到ActionMap，如：

 DoneImg.getActionMap().put("RightArrow", new SomeAction("RightArrow")); DoneImg.getActionMap().put("LeftArrow", new SomeAction("LeftArrow")); DoneImg.getActionMap().put("UpArrow", new SomeAction("UpArrow")); DoneImg.getActionMap().put("DownArrow", new SomeAction("DownArrow")); 

因此，您共享相同的基本function，但只需使用标识符标识每个Action。