简单的scala.swing应用程序失败

Question

我正在使用scalas运行一个简单的scala.swing应用程序：

#!/usr/bin/env scalas

/***         
scalaVersion := "2.12.6"
libraryDependencies += "org.scala-lang.modules" %% "scala-swing" % "2.1.1"
*/         


import scala.swing._

object FirstSwingApp extends SimpleSwingApplication {
  def top = new MainFrame {
    title = "First Swing App"
    contents = new Button {
      text = "Click me"
    }
  }
}

这段代码会编译并运行(在OSX 10.14上)，但是没有可见的输出；进程在几秒钟后终止。我做错了什么？

Answer 1

从文档判断，https://www.scala-sbt.org/release/docs/Scripts.html - scalas不像java -jar ...那样工作，也就是说，它不会在某些object中运行您的main类。

它只是像执行REPL一样执行代码，所以如果您想执行代码，请自己运行它：

#!/usr/bin/env scalas

/***         
scalaVersion := "2.12.6"
libraryDependencies += "org.scala-lang.modules" %% "scala-swing" % "2.1.1"
*/         


import scala.swing._

// creates object but doesn't run anything
object FirstSwingApp extends SimpleSwingApplication {
  def top = new MainFrame {
    title = "First Swing App"
    contents = new Button {
      text = "Click me"
    }
  }
}

FirstSwingApp.main(new Array[String](0)) // run main manually, or whatever you prefer