Passing parameters to custom TreeItem constructor

Question

Relatively new to Scala and ScalaFX but I've worked with Java and JavaFX before. My question is if there is a way to pass parameters to a custom TreeItem?

Code looks like this:

I'd like to do this:

def makePictureHolder(picture: Picture): TreeItem[Picture] = {
    new TemporaryHolderTreeItem(picture)
  }

With this:

class TemporaryHolderTreeItem extends TreeItem[Picture] {

  private val gridPane = new GridPane
  private val progressBar = new ProgressBar {
    prefWidth = 250
  }
  private val columnConstraints = ObservableBuffer(
    new ColumnConstraints(500),
    new ColumnConstraints(250)
  )

  def this(picture: Picture) = this() {
    value = picture

    gridPane.addColumn(0, new Label(resourceBundle
      .getString("uploadHolderText") + " " + picture.path))

    gridPane.addColumn(1, progressBar)

    gridPane.columnConstraints = columnConstraints
    graphic = gridPane
  }
}

But I get this error message:

TemporaryHolderTreeItem.scala:24: com.nodefactory.diehard.gail.views.TemporaryHolderTreeItem does not take parameters
[error]   def this(picture: Picture) = this() {
[error]

I tried placing the parameter picture in the class argument list but that does not work either. Like this:

class TemporaryHolderTreeItem(picture: Picture) extends TreeItem[Picture](picture) {

  private val gridPane = new GridPane
  private val progressBar = new ProgressBar {
    prefWidth = 250
  }
  private val columnConstraints = ObservableBuffer(
    new ColumnConstraints(500),
    new ColumnConstraints(250)
  )

  def this() = this() {
    gridPane.addColumn(0, new Label(resourceBundle
      .getString("uploadHolderText") + " " + picture.path))

    gridPane.addColumn(1, progressBar)

    gridPane.columnConstraints = columnConstraints
    graphic = gridPane
  }
}

Same error message as above.

score 0 · Accepted Answer · answered Jul 20 '17 at 12:51

Solution: I forget that the default constructor in Scala is outside of the functions so I did not need def this() = this() {...}

Instead this worked:

    class TemporaryHolderTreeItem(picture: Picture) extends TreeItem[Picture](picture) {

  private val gridPane = new GridPane
  private val progressBar = new ProgressBar {
    prefWidth = 250
  }
  private val columnConstraints = ObservableBuffer(
    new ColumnConstraints(500),
    new ColumnConstraints(250)
  )

  gridPane.addColumn(0, new Label(resourceBundle
    .getString("uploadHolderText") + " " + picture.path))

  gridPane.addColumn(1, progressBar)

  gridPane.columnConstraints = columnConstraints
  graphic = gridPane

}

Passing parameters to custom TreeItem constructor

1 Answers1