类JComboBox采用类型参数

Question

I want to get value of instance of JComboBox in my listener:

object NoteListener extends ActionListener {
  def actionPerformed(e:ActionEvent):Unit = {
    println("Source: " + e.getSource.asInstanceOf[JComboBox].getValue)
  }
}

And I get this error:

[error] .../test.scala:30:  class JComboBox takes type parameters
[error] println("Source: " + e.getSource.asInstanceOf[JComboBox].getValue)

when I try to pass any parameter:

[error] .../test.scala:30: ']' expected but '(' found.
[error] println("Source: " + e.getSource.asInstanceOf[JComboBox(Array)].getValue)

Is it a bug, or my ignorance?

Answer 1

Your type parameters are incorrect:

e.getSource.asInstanceOf[JComboBox(Array)].getValue)

should be

e.getSource.asInstanceOf[JComboBox[Array]].getValue)

Note the [Array]. This is how you specify type parameters in Scala.

Answer 2

不确定，但这应为您提供JComboBox的实例

e.getSource.peer