CS 424524: Introduction to Java Programming

1
CS 424/524 Introduction to Java Programming

• Lecture 24
• Spring 2002
• Department of Computer Science
• University of Alabama
• Joel Jones

2
Overview

• Questions
• Handout MP
• Review GUI Development
• Developing Swing Applications
• Exercise for next time
• Reading for next time

3
Review Steps in Designing a GUI Application

• Iteratively
• Analyze the problem
• Design the model
• Design the graphical layout
• Write unit test for model
• Write unit test for GUI
• Write code for model
• Write code for GUI

Pair Up Why would you choose command-line?
text-file? GUI?
4
Simple HR Database

• Analyze the Problem
• Elicit requirements from Human Relations
  Department
• Want to send invitations to picnic
• Need to know how many veggie pizzas to order
• Need to plan games
• Want to give Years of Service awards

5
Simple HR Database (cont.)

• Analyze the Problem (cont.)
• Turn into simple data items
• first name
• last name
• sport
• of years
• Vegetarian?
• Design the model
• simple 2-d array of Objects

6
Simple HR Database (cont.)

• Design the GUI

7
Simple HR Database (cont.)

• Write unit test for model
• Our model (2-d array of Objects) has no behavior
• Therefore, no unit test or code to implement
• Write unit test for GUI
• Ignore for expediency
• Write code for GUI
• Use JTable
• But how does JTable work?

8
Using JTable

• See code printout (SimpleTableLayout)
• Simplest JTable constructor uses
• 2-d array of objects as model
• String array of column names
• This constructor is easy to use, but
• Everything is editable
• All data types treated the same
• Stupid Inappropriate model

9
Using JTable (cont.)

• The appearance of columns can be controlled
• TableColumn column getColumnModel().getColumn(i)
  
• column.setPreferredWidth(100)
• setAutoResizeMode()

10
Using JTable (cont.)

• Model for JTable must subclass AbstractTableModel
  abstract class
• But this isnt hard, the default one is code like
  that found in handout

11
Using JTable (cont.)

• Lets change behavior
• Dont let user edit first or last names
• Use check boxes for Vegetarian? column
• See TableDemo code in handout
• What if model can change not through the view
  (JTable)?
• firefoo methods of AbstractTableModel

12
Using JTable (cont.)

• What is going on with the checkbox?
• Default Cell Editor and Renderer
• The defaults are
• Boolean check box
• Number right-aligned box
• ImageIcon centered label
• Object label that displays objects string
  value
• How do use my own Cell Editor?
• table.setDefaultEditor(Class, DefaultCellEditor)

13
MP2 Demo
14
Further Reading

• Java Tutorial on JTable
• http//java.sun.com/docs/books/tutorial/uiswing/co
  mponents/table.html