Java開關與用戶輸入擊鍵

Question

我正在Java中做蛇遊戲，需要使用用戶擊鍵來控制移動的方向。這可能通過switch聲明嗎？我最初使用Scanner s = new Scanner(System.in)來允許用戶輸入'u'，'d'等來移動蛇，但我想用鍵盤箭頭代替。

這是我現在所擁有的：

public void controlSnake(){ 

Scanner s = new Scanner(System.in); 
String inputString = s.next(); 

    switch (inputString) { 
    case "u": 
    case "U": 
     snake.changeDirection(Point.NORTH); 
     break; 
    case "d": 
    case "D": 
     snake.changeDirection(Point.SOUTH); 
     break; 
    case "r": 
    case "R": 
     snake.changeDirection(Point.EAST); 
     break; 
    case "l": 
    case "L": 
     snake.changeDirection(Point.WEST); 
     break; 
    } 

} 

我要插入這樣的事情，但不知道如何：

 map1.put(KeyStroke.getKeyStroke("LEFT"), "moveLeft"); 

    getActionMap().put("moveLeft", new AbstractAction() { 
    private static final long serialVersionUID = 1L; 

    public void actionPerformed(ActionEvent e) { 
    snake.changeDirection(Point.WEST); 

    } 
    }); 

什麼是做到這一點的最好辦法？

Answer 1

我看到你在使用Swing。您可以使用KeyListener接口。像這樣的東西。

yourButton.addKeyListener(new KeyListener(){ 
     @Override 
      public void keyPressed(KeyEvent e) { 
       if(e.getKeyCode() == KeyEvent.VK_UP){ 
        snake.changeDirection(Point.NORTH); 
       } 
       if(e.getKeyCode() == KeyEvent.VK_DOWN){ 
        snake.changeDirection(Point.SOUTH); 
       } 
       //Likewise for left and right arrows 
      } 

      @Override 
      public void keyTyped(KeyEvent e) { 
       throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates. 
      } 

      @Override 
      public void keyReleased(KeyEvent e) { 
       throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates. 
      } 
    }); 

Answer 2

它可以從JDK 7使用switch語句與String：

Strings in switch Statements

，似乎你正在開發一個控制檯遊戲。如果您使用的鞦韆，您可以考慮使用InputMap連同ActionMap代替：

How to Use Key Bindings