swing - Scala Swing 中的听众和 react

Question

我在 Eclipse 中进行了相当多的搜索和一些试验和错误，但在使用 Swing 在 Scala 中编写 GUI 时，我对监听器和 react 的理解似乎存在差距。

每个监听器是否都会获得一个 react block ，或者我是否在可能生成事件的所有组件上注册监听器，并使用 case 语句对大型 react block 中的每个组件使用react？

听众和 react block 到底属于哪里。

这是我的 GUI 代码的缩写版本:

import scala.swing._
import scala.swing.event.ButtonClicked
import scala.swing.event.KeyTyped
import scala.swing.event.KeyPressed

object HumanGUI extends SimpleGUIApplication {

 val basicPane = new java.awt.Dimension(800, 200)
 val botPane = new java.awt.Dimension(400, 200)
 val felt = new java.awt.Color(35, 125, 35)

 def top = new MainFrame {

    title = "Blackjack GUI"

    val ConnectionPanel = new BoxPanel(Orientation.Vertical) {
      background = felt
      preferredSize = new java.awt.Dimension(155, 90)
      minimumSize = preferredSize
      maximumSize = preferredSize

      val ipAddressLabel = new Label("House IP:")
      ipAddressLabel.foreground = java.awt.Color.WHITE
      ipAddressLabel.horizontalTextPosition = scala.swing.Alignment.Left

      val portLabel = new Label("House port:")
      portLabel.foreground = java.awt.Color.WHITE
      portLabel.horizontalTextPosition = scala.swing.Alignment.Left

      val ipAddressTextField = new TextField
      val portTextField = new TextField

      contents += ipAddressLabel
      contents += ipAddressTextField
      contents += portLabel
      contents += portTextField
    }

    val DetailPanel = new BoxPanel(Orientation.Vertical) {
      background = felt
      preferredSize = new java.awt.Dimension(100, 160)
      minimumSize = preferredSize
      maximumSize = preferredSize

      val nameLabel = new Label("Your name:")
      nameLabel.foreground = java.awt.Color.WHITE
      nameLabel.horizontalTextPosition = scala.swing.Alignment.Left

      val bankrollLabel = new Label("Bankroll:")
      bankrollLabel.foreground = java.awt.Color.WHITE
      bankrollLabel.horizontalTextPosition = scala.swing.Alignment.Left

      val betLabel = new Label("Bet:")
      betLabel.foreground = java.awt.Color.WHITE
      betLabel.horizontalTextPosition = scala.swing.Alignment.Left

      val nameTextField = new TextField
      val bankrollTextField = new TextField
      val betTextField = new TextField

      val goButton = new Button("Go!")

      contents += nameLabel
      contents += nameTextField
      contents += bankrollLabel
      contents += bankrollTextField
      contents += betLabel
      contents += betTextField
      contents += goButton
    }

    val PlayPanel = new BoxPanel(Orientation.Vertical) {
      background = felt
      val hitButton = new Button("Hit")
      val stayButton = new Button("Stay")
      val doubleButton = new Button("Double")
      val quitButton = new Button("Quit")

      contents += hitButton
      contents += stayButton
      contents += doubleButton
      contents += quitButton
    }

    val playerPanel = new BoxPanel(Orientation.Horizontal) {
      background = felt
      border = new javax.swing.border.LineBorder(java.awt.Color.WHITE)
      preferredSize = basicPane
      minimumSize = basicPane
      maximumSize = basicPane
      opaque = true

      contents += ConnectionPanel
      contents += DetailPanel
      contents += PlayPanel
    }

    contents = new BoxPanel(Orientation.Vertical) {
      contents += playerPanel
    }
  }
}

所以问题是我应该把听众和 react block 放在哪里？
我想对 PlayPanel 中的按钮以及 ConnectionPanel 和 DetailPanel 中的文本字段使用react。
我是否将监听器和 react block 放置在尽可能靠近我感兴趣的元素的位置，或者是否将一大块监听器和 react block 放置在 MainFrame 部分的末尾？
这还重要吗？

编辑
我已经取得了显着的进步，并且掌握了许多我需要的东西，并且对我以前没有得到的概念有了更好的理解。

Odersky 的“Scala 编程”的这段摘录对我帮助最大。具体来说，此页面的示例:

http://www.artima.com/pins1ed/gui-programming.html

代码来自文本的第一版，所以我怀疑Scala 2.9是否有更好的方法，但它很清楚，简洁，总结了我的误解。

从这个简单的华氏到摄氏转换器的示例中，我了解到监听器和 react block 属于 MainFrame 的内容 block 之后。

所以我最终得到:

object HumanGUI extends SimpleSwingGUIApplication {
  def top = new MainFrame {
    title = "My Blackjack GUI"

    //The fields I want to work with are instantiated as object
    object ipAddressTextField extends TextField { columns = 15 }
    object portNumberTextField extends TextField {columns = 5 }

    //other panels, objects, etc would go here
    val OtherPanel = new BoxPanel(Orientation.Horizontal) {
       label = "Other Panel"
    }

    //and here we have the contents += block for the mainframe, other panels, etc from 
    //above would be added to the main frame here
    contents = new BoxPanel(Orientation.Vertical) {
      contents += ipAddressTextField
      contents += portNumberTextField
    }

    //here's the listen to, listening on the object created above, and it's enclosed in 
    //in backticks, a good explanation of that is found in the link below
    listenTo(`ipAddressTextField`)
    reactions += {
      case EditDone('ipAddressTextField`) =>
        //do something!
    }
  }

Need clarification on Scala literal identifiers (backticks)

所以看来我的问题的答案是listenTo和reactions block 属于MainFrame block ，但应该出现在它的contents += {//contents } block 之后。

Eclipse 中的额外试验和错误表明，虽然这个解决方案对我有用，但显然还有更多我不明白的地方。例如，虽然我无法让 KeyPress 事件的监听器工作，但如果我尝试在
中监听它们并对它们使用react val OtherPanel = new BoxPanel(Orientation.Horizo​​ntal) { }
上面代码的一部分，我能够注册一个按钮并像这样工作:

val OtherPanel = new BoxPanel(Orientation.Horizontal) {
  val betLabel = new Label("Bet:")
  val betTextField = new TextField
  val goButton = new Button("Go!")

  listenTo(goButton)
  reactions += {
    case ButtonClicked(b) =>
      betTextField.text = "Go!"
  }

  contents += betLabel
  contents += betTextField
  contents += goButton
}

为什么这有效，但我尝试做一些类似的事情

val OtherPanel = new BoxPanel(Orientation.Horizontal) {
  val betLabel = new Label("Bet:")
  val betTextField = new TextField
  val goButton = new Button("Go!")

listenTo(betTextField)
reactions += {
  case KeyTyped(betTextField, Enter, _, _) => {
    println("Caught enter")
  }

  contents += betLabel
  contents += betTextField
  contents += goButton
}

没有工作仍然让我困惑。我假设它应该有效，但我只是做错了事。也许将该方法与案例 EditDone 而不是案例 KeyTyped(,,,) 融合会起作用，但我现在有点太累了，无法跟进关于这一点。

我还没有接受答案，因为我希望看到这个的人能够澄清我仍然不明白的观点。如果这种情况没有发生，并且问题几天后仍未得到解答，我可能会接受 @som-snytt 的回答，因为他的代码非常有帮助。

Answer 1

Swing 具有教育意义，Scala-Swing 具有教育意义。特别是如果类(class)是“Swing 史:兴衰”。

我的第一个 Scala 程序也使用了 Swing。我忘记了细节，但我会分享我在源代码中看到的内容。

显然，我有一个名为 LightBox 的主 UI 组件，用于处理一些 UI 事件，还有一个协调的中介组件 LightBoxMediator。

有趣的部分是，使用蛋糕模式进行组合，并将业务逻辑(或游戏逻辑)交互转移到一个为 UI 适当“调解”的组件中。 LightBox 也发布事件。

所以你的问题的答案是:利用发布者框架，但区分 UI 事件和应用程序事件。 (这个小游戏也有基于角色的 Controller 。)

也许这足以说明关注点的分离:

/**
 * Draws the House of Mirrors.
 * The LightBox is just a list of rays (line segments) and gates (various objects).
 * The UI emits requests to move and rotate gates.
 */
class LightBox extends Panel {

  this.peer.addComponentListener(
    new ComponentAdapter {
      override def componentResized(e: ComponentEvent) {
        if (e.getID == ComponentEvent.COMPONENT_RESIZED && e.getComponent == LightBox.this.peer) {
          calculateScale()
        }
      }
    }
  )

  listenTo(mouse.clicks, mouse.moves, mouse.wheel, keys)

  reactions += {
    case KeyPressed(_, Key.N, _, _) => highlightNextMoveableGate()
    case KeyPressed(_, Key.P, _, _) => highlightPreviousMoveableGate()
    case e: MousePressed => startDrag(e)
    case e: MouseDragged => doDrag(e)
    case e: MouseReleased => endDrag(e)
    case e: MouseWheelMoved => wheeling(e)
    case _ => null // println ("Unreacted event")
  }

和中介

trait ViewComponents {
  this: ControllerComponents with ModelComponents =>

  val lightBoxMediator: LightBoxMediator
  val statusBarMediator: StatusBarMediator
  val statusIconMediator: StatusIconMediator
  val applicationMediator: ApplicationMediator

  /**
   * Handles update notifications from the application
   * and user input from the LightBox.
   */
  class LightBoxMediator(val ui: LightBox) extends Reactor with Observing {

    /** Attempt to track our selection across updates: the point is where the gate should end up. */
    private var selectionContinuity: (Option[Gate], Option[Point]) = (None, None)

    listenTo(ui, ui.keys, ui.mouse.clicks)

    reactions += {
      case KeyPressed(_, Key.Q, _, _) => sys.exit()
      case KeyPressed(_, Key.Space, _, _) => rotateSelectedGate()
      case KeyPressed(_, Key.Enter, _, _) => rotateOtherwiseSelectedGate()
      case KeyPressed(_, Key.Up, _, _) => moveUp()
      case KeyPressed(_, Key.Down, _, _) => moveDown()
      case KeyPressed(_, Key.Left, _, _) => moveLeft()
      case KeyPressed(_, Key.Right, _, _) => moveRight()
      case KeyPressed(_, Key.PageUp, _, _) => previousLevel()
      case KeyPressed(_, Key.PageDown, _, _) => nextLevel()
      case DragEvent(from, to) => handleDrag(from, to)
      case ClickEvent(where, button) => handleClick(where, button)
      //case x => println("Unreacted event " + x)
    }

    observe(controller.modelEvents) { e => e match {
        case LevelLoaded(v) => onLevelLoaded(v)
        case TraceResult(s) => onTrace(s)
        case unknown => println("Lightbox mediator ignored: "+ unknown)
      }
      true
    }

刚刚注意到其他问题。巧合的是，我正在清理旧代码，实际上是一个从 sfgate.com 抓取图像的小应用程序(当然，当他们更改网站时，它停止工作；但通常你现在可以右键单击保存)，我碰巧请注意以下有关重新订阅的评论。我依稀记得 UIElement 是一个 LazyPublisher 的事情，因为我记得那一巴掌。但如果我没有写下这条微不足道的评论，这些信息就会消失在古代历史中。

我认为有人想要支持 scala-swing 并且可能会处理头部问题。

package com.maqicode.sfg.jfc

import java.awt.Color
import java.awt.Color.{WHITE => White, RED => Red}
import java.net.{URI, URISyntaxException}
import javax.swing._

import swing.TextField
import swing.event.{EditDone, MouseEntered, ValueChanged}

import com.maqicode.sfg.BadGateURLException
import com.maqicode.sfg.GateUrlTranslator.translate

abstract class URIField extends TextField {

  reactions += {
    case e: EditDone => editDone(e)
    case other: ValueChanged => editing(other)
    case m: MouseEntered => onMouseEntered()
    case _ => null
  }
  // necessary to resubscribe this so that onFirstSubscribe registers ActionListener
  listenTo(this, mouse.moves)

  def onMouseEntered() {
    val t: Option[String] = ClipboardInput.contents
    if (t.isDefined && t.get != this.text) {
      this.text = t.get
      submitURL(t.get)
    }
  }

  def editing(e: ValueChanged) {
    clearError()
  }

  def editDone(e: EditDone) {
    submitURL(this.text)
  }

  def submitURL(s: String) {
    val u = s.trim
    if (!u.isEmpty)
      try {
        submitURI(translate(new URI(u)))
        clearError()
      } catch {
        case t: BadGateURLException => flagError()
        case t: URISyntaxException => flagError()
      }
  }

  def flagError() {
    colorCode(Red)
  }

  def clearError() {
    colorCode(White)
  }

  private def colorCode(c: Color) {
    if (this.background != c) this.background = c
  }

  def submitURI(uri: URI): Unit
}