Scala学习整理[第三十二章 GUI编程]<Programming In Scala>

第三十二章 GUI编程

package SecondWithProgrammingInScala

import java.io.File

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

/**
* GUI 编程
* 大致的使用和实际效果和JavaSwing没啥区别
* 之前使用过Swing和Vaadin(Java->Html/js) ,相比浏览器流派 ,Java客户端适用性还是低一些的
*
*
* 使用swing时候出现了版本问题
* scala在2.10以后对模块进行了比较大的划分 ,不少包被拆分成了不同的模块
* 使用maven关联要注意
* 以scala-library为核心 ,核心版本号2.12去关联其他模块包
* 官方还提供了一个scala-lang-all ,包括了之前拆分出去的包
*
*/
object ScalaSwingApp extends SimpleSwingApplication {
/**
* 和Java编写方式不同 ,Java大多将参数通过构造函数传递进去
* Button okBtn = new Button(text = ok)
* scala而多是使用{}直接重载里面的属性(实质是匿名子类) ,更符合实际 ,不同功能的按钮就是不同的类.
* val okBtn = new Button{override text = ok}
* :  new OkButton{override text = ok} extends Button
*/
//设置程序主窗口
override def top: Frame = new MainFrame {
//窗口标题
title = "Scala Swing App"
//注册组件
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"
}
//设置窗口内容(布局){组件}
contents = new BoxPanel(Orientation.Vertical) {
//这里的contents是指BoxPanel布局的内容
contents += clickBtn
contents += clickBlueBtn
contents += tipL
border = Swing.EmptyBorder(30, 30, 10, 30)
}
//设置监听
listenTo(clickBtn, clickBlueBtn)
//设置监听回调函数
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
}
}
}
}

/**
* 简单计算器
*/
object Calculation extends SimpleSwingApplication {
override def top: Frame = new MainFrame {
title = "简单计算器"

//文本组件
object Elem1 extends TextField {
columns = 5
}

object Elem2 extends TextField {
columns = 5
}

object Func extends TextField {
columns = 2
}

object Result extends TextField {
columns = 20
}

//提示组件
val tips_defualt = "请输入要计算的值[0-9]和运算符[+-*/]"
val tipsL = new Label(tips_defualt)
//设置布局
contents = new BoxPanel(Orientation.Vertical) {
//设置提示
contents += tipsL
//设置输入框
contents += new BoxPanel(Orientation.Horizontal) {
contents += Elem1
contents += new Label("     ")
contents += Func
contents += new Label("     ")
contents += Elem2
}
//设置结果
contents += Result
border = Swing.EmptyBorder(30, 30, 30, 30)
}
//设置动作
var errors = 0
listenTo(Elem1, Elem2, Func)

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

//设置计算函数
def calculate: Unit = {
try {
//复原提示
tipsL.text = tips_defualt
//检查运算符并试图转换数值
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_=("运算符输入错误 ,请重新输入")
}
} catch {
//数值转换出错
case e: NumberFormatException => tipsL.text_=("数值输出错误 ,请重新输入")
case e => tipsL.text_=(e.getMessage)
}
}
}
}