Scala Swing：如何使用鼠标平移图像？

Question

我一直在尝试在Scala中复制一些Java Swing工作。在下面的代码中this扩展了Scala Swings ScrollPane。

myPanel.reactions +={
    case MouseDragged(_,x,_) => {
      //val viewport = this.viewportView.get.asInstanceOf[JViewport]
      val viewport = this.contents.head.self.asInstanceOf[JComponent].getParent.asInstanceOf[JViewport]
      println(viewport.getViewPosition)
      val vp = viewport.getViewPosition
      var cp = x.getLocation
      vp.translate(point.x-cp.x,point.y-cp.y)
      //newLoc = new Point(vp.getX)
      val jComp = contents.head.asInstanceOf[JComponent]
      jComp.scrollRectToVisible(new Rectangle(vp,viewport.getSize: Dimension))
    }
    case MousePressed(_,x,_,_,_) => point = x.getLocation
    case MouseClicked(_,_,_,_,_) => println("click")
}

我无法在相关问题的Java代码中看到如何访问Viewport对象。如何在Scala Swing中实现它？

Answer 1

  myPanel.reactions +={
    case MouseDragged(myPanel,x,_) => {
      val cp = x.getLocation
      this.horizontalScrollBar.value += point.x-cp.x
      this.verticalScrollBar.value += point.y-cp.y
      point = cp
    }
    case MousePressed(_,x,_,_,_) => point = x.getLocation
  }