Scala example source code file (ComboBoxes.scala)

This example Scala source code file (ComboBoxes.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

awt, boolean, boolean, combobox, combobox, comboboxes, couldn't, date, gui, imageicon, imageicon, label, list, list, mmm, selectionchanged, swing, text, util

The Scala ComboBoxes.scala source code

package scala.swing
package test

import swing._
import event._
import java.util.Date
import java.awt.Color
import java.text.SimpleDateFormat
import javax.swing.{Icon, ImageIcon}

/**
 * Demonstrates how to use combo boxes and custom item renderers.
 * 
 * TODO: clean up layout
 */
object ComboBoxes extends SimpleSwingApplication {
  import ComboBox._
  lazy val ui = new FlowPanel {
   	contents += new ComboBox(List(1,2,3,4))
        
    val patterns = List("dd MMMMM yyyy",
                        "dd.MM.yy",
                        "MM/dd/yy",
                        "yyyy.MM.dd G 'at' hh:mm:ss z",
                        "EEE, MMM d, ''yy",
                        "h:mm a",
                        "H:mm:ss:SSS",
                        "K:mm a,z",
                        "yyyy.MMMMM.dd GGG hh:mm aaa")
    val dateBox = new ComboBox(patterns) { makeEditable() }
    contents += dateBox
    val field = new TextField(20) { editable = false }
    contents += field
    
    reactions += {
      case SelectionChanged(`dateBox`) => reformat()
    }
    listenTo(dateBox.selection)
    
    def reformat() {
      try {
        val today = new Date
        val formatter = new SimpleDateFormat(dateBox.selection.item)
        val dateString = formatter.format(today)
        field.foreground = Color.black
        field.text = dateString
      } catch {
        case e: IllegalArgumentException =>
          field.foreground = Color.red
          field.text = "Error: " + e.getMessage
      }
    }
    
    
    val icons = try { 
      List(new ImageIcon(resourceFromClassloader("images/margarita1.jpg")),
           new ImageIcon(resourceFromClassloader("images/margarita2.jpg")), 
           new ImageIcon(resourceFromClassloader("images/rose.jpg")),
           new ImageIcon(resourceFromClassloader("images/banana.jpg")))
    } catch {
      case _ => 
        println("Couldn't load images for combo box")
        List(Swing.EmptyIcon)
    }

    val iconBox = new ComboBox(icons) {
      renderer = new ListView.AbstractRenderer[Icon, Label](new Label) {
        def configure(list: ListView[_], isSelected: Boolean, focused: Boolean, icon: Icon, index: Int) {
  	      component.icon = icon
          component.xAlignment = Alignment.Center
          if(isSelected) {
            component.border = Swing.LineBorder(list.selectionBackground, 3)
          } else {
            component.border = Swing.EmptyBorder(3)
          }
        }
      }
    }
    contents += iconBox
  }
    
  def top = new MainFrame {
    title = "ComboBoxes Demo"
   	contents = ui
  }
}