scala/ScalaBook/chapter-06/dialog8.scala

import scala.swing._
import scala.swing.event._
object dialog extends SimpleGUIApplication {
  def top = new MainFrame {
    title = "Greetings"
    preferredSize = (250,180)
    val label = new Label {
      text = "Hello World!"
      font = new java.awt.Font("Verdana",
                                java.awt.Font.BOLD, 22)
    }
    contents = new GridBagPanel { mypanel =>
      var c = new Constraints
      c.gridwidth = java.awt.GridBagConstraints.REMAINDER
      add(label,c)
      add(Swing.VStrut(20), c)
      layout(new Button(Action("Close Window") {
        import Dialog._        
        var s = showConfirmation(mypanel, "Are you sure?", 
                                 "Close Window", 
                                 Options.OkCancel, 
                                 Message.Question,null)
        if ( s == Result.Ok )
          exit(0)
      }){ font = new java.awt.Font("Verdana",
                                    java.awt.Font.PLAIN, 14)}) = c
      background = java.awt.Color.yellow
      border = Swing.EmptyBorder(50, 50, 50, 50)
    }
  }
}