我如何消耗斯卡拉反应

Question

假设有作为

this.reactions += { 
    case KeyReleased(src, key, mod, _) => { 
    // do some stuff 
    // but how to consume this KeyEvent?? 
    } 
} 

doint后“一些东西”我想占用该KeyEvent一个“反应”块这样的关键事件，但我不知道怎么办。展望上Component.scala来源我已经找到了如何在构造的keyReleased事件：

object keys extends Publisher { 
    peer.addKeyListener(new KeyListener { 
    def keyPressed(e: java.awt.event.KeyEvent) { publish(new KeyPressed(e)) } 
    def keyReleased(e: java.awt.event.KeyEvent) { publish(new KeyReleased(e)) } 
    def keyTyped(e: java.awt.event.KeyEvent) { publish(new KeyTyped(e)) } 
    }) 
} 

的java.awt.event.KeyEvent中被用作构造函数的参数，但调用keyReleased 案例类有这个签名

case class KeyReleased(val source: Component, key: Key.Value, val modifiers: Key.Modifiers, 
       location: Key.Location.Value) 
       (val peer: java.awt.event.KeyEvent) extends KeyEvent { 
def this(e: java.awt.event.KeyEvent) = 
this(UIElement.cachedWrapper[Component](e.getSource.asInstanceOf[JComponent]), 
    Key(e.getKeyCode), e.getModifiersEx, Key.Location(e.getKeyLocation))(e) 
} 

因此我无法访问KeyEvent参数。

Answer 1

您不必在case语句反应中解开KeyReleased事件。只需匹配事件本身就可以让你调用消耗。

reactions += { 
    case e: KeyReleased => { 
     println(e.source, e.key, e.modifiers) 
     e.consume 
    } 
}