Question

I whould like to create a scala Views helper for Android

Using this combination of trait and class

class ScalaView(view: View) {
  def onClick(action: View => Any) =
    view.setOnClickListener(new OnClickListener {
      def onClick(view: View) {
        action(view)
      }
    })
}

trait ScalaViewTrait {
  implicit def view2ScalaView(view: View) =
    new ScalaView(view)
}

I’m able to write onClick() like so

class MainActivity extends Activity with ScalaViewTrait {
//....
val textView = new TextView(this)
textView.onClick(v => v.asInstanceOf[TextView] setText ("asdas"))
}

My concern is that i want to avoid casting v to TextView

v will always be TextView if is applied to a TextView LinearLayout if applied to LinearLayout and so on.

Is there any way that v gets dynamic casted to whatever view is applied?

Just started with Scala and i need your help with this.

UPDATE

Solved see my answer below

Answer 1

I managed to do it.
Here is how

trait ScalaViewTrait {
  implicit def view2ScalaView[T <: View](view: T) =
    new ScalaView[T](view)
}

class ScalaView[T <: View](view: T) {
  def onClick(action: T => Any) =
    view.setOnClickListener(new OnClickListener {
      def onClick(view: View) {
        action(view.asInstanceOf[T])
      }
    })
}

And now i can write onClick like this

textView.onClick(v => v.setText("asdsa"))

v is actually a TextView when onClick is applied to a TextView

PS. Maybe i’ll write a bunch of helpers and publish them on GitHub. <3 Scala