I am very close to finish my to do list application but there is a slight error

Question

This is a to-do list application that i made as a beginner. However, there is an error that says missing parameter type in this line of code:

todoTable.selectionModel().selectedItem.onChange(
  (_, newValue) => showTodoDetails(Some(newValue))

)

I can't figure out what the problem is as I had no issue running with it earlier. And it also seems to be the only error that keeps me from finishing the to-do application program.

Below is the file that is having an error

package ch.makery.address.view

import ch.makery.address.model.Todo
import ch.makery.address.MainApp

import scalafx.scene.control.{Alert, Label, TableColumn, TableView}
import scalafxml.core.macros.sfxml
import scalafx.beans.property.StringProperty
import scala.util.{Failure, Success}
import scalafx.Includes._
import scalafx.event.ActionEvent
import scalafx.scene.control.Alert.AlertType

@sfxml
class TodoOverviewController(
  
    private val todoTable : TableView[Todo],
   
    private val titleColumn : TableColumn[Todo, String],

    private val titleLabel : Label,
  
    private val descriptionLabel : Label
    
    ) {
  // initialize Table View display contents model
  todoTable.items = MainApp.todoData
  // initialize columns's cell values
  titleColumn.cellValueFactory = {_.value.title}
  
  showTodoDetails(None);
  
  todoTable.selectionModel().selectedItem.onChange(
      (_, newValue) => showTodoDetails(Some(newValue))
  )
  
  private def showTodoDetails (todo : Option[Todo]) = {
    todo match {
      case Some(todo) =>
      // Fill the labels with info from the todo object.
      titleLabel.text <== todo.title
      descriptionLabel.text <== todo.description
      case None =>
        // todo is null, remove all the text.
      titleLabel.text = ""
      descriptionLabel.text = ""
    }    
  }
  def handleNewTodo(action : ActionEvent) = {
    val todo = new Todo("")
    val okClicked = MainApp.showTodoEditDialog(todo);
        if (okClicked) {
          todo.save() match {
            case Success(x) =>
              MainApp.todoData += todo
            case Failure(e) =>
              val alert = new Alert(Alert.AlertType.Warning) {
                initOwner(MainApp.stage)
                title = "Failed to Save"
                headerText = "Database Error"
                contentText = "Database problem filed to save changes"
              }.showAndWait()
          }
        }
  }
  def handleEditTodo(action : ActionEvent) = {
    val selectedTodo = todoTable.selectionModel().selectedItem.value
    if (selectedTodo != null) {
        val okClicked = MainApp.showTodoEditDialog(selectedTodo)

        if (okClicked) {
          selectedTodo.save() match {
            case Success(x) =>
              showTodoDetails(Some(selectedTodo))
            case Failure(e) =>
              val alert = new Alert(Alert.AlertType.Warning) {
                initOwner(MainApp.stage)
                title = "Failed to Save"
                headerText = "Database Error"
                contentText = "Database problem filed to save changes"
              }.showAndWait()
          }
        }

    } else {
        // Nothing selected.
        val alert = new Alert(Alert.AlertType.Warning){
          initOwner(MainApp.stage)
          title       = "No Selection"
          headerText  = "No Todo Selected"
          contentText = "Please select a todo in the table."
        }.showAndWait()
    }
  }
    def handleDeleteTodo(action : ActionEvent) = {
      val selectedIndex = todoTable.selectionModel().selectedIndex.value
      val selectedTodo = todoTable.selectionModel().selectedItem.value
      if (selectedIndex >= 0) {
        selectedTodo.save() match {
          case Success(x) =>
            todoTable.items().remove(selectedIndex);
          case Failure(e) =>
            val alert = new Alert(Alert.AlertType.Warning) {
              initOwner(MainApp.stage)
              title = "Failed to Save"
              headerText = "Database Error"
              contentText = "Database problem filed to save changes"
            }.showAndWait()
        }
      } else {
        // Nothing selected.
        val alert = new Alert(AlertType.Warning){
          initOwner(MainApp.stage)
          title       = "No Selection"
          headerText  = "No Todo Selected"
          contentText = "Please select a todo in the table."
        }.showAndWait()
      }
    }


  }

Answer 1

The function passed to onChange takes 3 arguments, not 2, you should have

    todoTable.selectionModel().selectedItem.onChange(
      (_, _, newValue) => showTodoDetails(Some(newValue))
    )