Scala學習整理[第三十二章 GUI編程]

第三十二章 GUI編程

package SecondWithProgrammingInScala

import java.io.File

import scala.swing.{TextField, _}
import scala.swing.event.{ButtonClicked, EditDone}

/**
  * GUI 編程
  * 大致的使用和實際效果和JavaSwing沒啥區別
  * 之前使用過Swing和Vaadin(Java->Html/js) ,相比瀏覽器流派 ,Java客戶端適用性還是低一些的
  *
  *
  * 使用swing時候出現了版本問題
  * scala在2.10以後對模塊進行了比較大的劃分 ,不少包被拆分成了不同的模塊
  * 使用maven關聯要注意
  * 以scala-library爲核心 ,核心版本號2.12去關聯其他模塊包
  * 官方還提供了一個scala-lang-all ,包括了之前拆分出去的包
  *
  */
object ScalaSwingApp extends SimpleSwingApplication {
  /**
    * 和Java編寫方式不同 ,Java大多將參數通過構造函數傳遞進去
    * Button okBtn = new Button(text = ok)
    * scala而多是使用{}直接重載裏面的屬性(實質是匿名子類) ,更符合實際 ,不同功能的按鈕就是不同的類.
    * val okBtn = new Button{override text = ok}
    * :  new OkButton{override text = ok} extends Button
    */
  //設置程序主窗口
  override def top: Frame = new MainFrame {
    //窗口標題
    title = "Scala Swing App"
    //註冊組件
    val clickBtn = new Button {
      text = "Click me"
    }
    val clickBlueBtn = new Button {
      background = java.awt.Color.BLUE
      text = "Click me"
    }
    val tipL = new Label {
      text = "No button clicks registered"
    }
    //設置窗口內容(佈局){組件}
    contents = new BoxPanel(Orientation.Vertical) {
      //這裏的contents是指BoxPanel佈局的內容
      contents += clickBtn
      contents += clickBlueBtn
      contents += tipL
      border = Swing.EmptyBorder(30, 30, 10, 30)
    }
    //設置監聽
    listenTo(clickBtn, clickBlueBtn)
    //設置監聽回調函數
    var nClicks = 0
    reactions += {
      case ButtonClicked(btn) => {
        nClicks += 1
        if (btn == clickBlueBtn) tipL.text = "You just Click the Blue Button:" + nClicks
        else tipL.text = "Number of button Clicks:" + nClicks
      }
    }
  }
}

/**
  * 簡單計算器
  */
object Calculation extends SimpleSwingApplication {
  override def top: Frame = new MainFrame {
    title = "簡單計算器"

    //文本組件
    object Elem1 extends TextField {
      columns = 5
    }

    object Elem2 extends TextField {
      columns = 5
    }

    object Func extends TextField {
      columns = 2
    }

    object Result extends TextField {
      columns = 20
    }

    //提示組件
    val tips_defualt = "請輸入要計算的值[0-9]和運算符[+-*/]"
    val tipsL = new Label(tips_defualt)
    //設置佈局
    contents = new BoxPanel(Orientation.Vertical) {
      //設置提示
      contents += tipsL
      //設置輸入框
      contents += new BoxPanel(Orientation.Horizontal) {
        contents += Elem1
        contents += new Label("     ")
        contents += Func
        contents += new Label("     ")
        contents += Elem2
      }
      //設置結果
      contents += Result
      border = Swing.EmptyBorder(30, 30, 30, 30)
    }
    //設置動作
    var errors = 0
    listenTo(Elem1, Elem2, Func)

    reactions += {
      //輸入完成
      case EditDone(_) => calculate
    }

    //設置計算函數
    def calculate: Unit = {
      try {
        //復原提示
        tipsL.text = tips_defualt
        //檢查運算符並試圖轉換數值
        Func.text match {
          case "+" => Result.text = (Elem1.text.toInt + Elem2.text.toInt).toString
          case "-" => Result.text = (Elem1.text.toInt - Elem2.text.toInt).toString
          case "*" => Result.text = (Elem1.text.toInt * Elem2.text.toInt).toString
          case "/" => Result.text = (Elem1.text.toInt / Elem2.text.toInt).toString
          case _ => tipsL.text_=("運算符輸入錯誤 ,請重新輸入")
        }
      } catch {
        //數值轉換出錯
        case e: NumberFormatException => tipsL.text_=("數值輸出錯誤 ,請重新輸入")
        case e => tipsL.text_=(e.getMessage)
      }
    }
  }
}