QMCS 230: Today in Class

1
QMCS 230 Today in Class

• Administrative
• Office Hours Today CANCELED
• Project Schedule
• This Week Schedule
• About the Exam
• Graphical User Interface (GUI)
• See how far we get

2
This Week Schedule

• Lecture/Lab Tomorrow
• Lab Wednesday
• LABS DUE
• I will accept Lab 16 THIS WEEK
• Deduct from grade for being late
• Same with Lab 17 if not received tomorrow
• Lab 18 due NEXT Tuesday

3
Project Schedule

• Team and project THIS WEEK
• Tell me next Monday
• What youre doing who youre working with
• Design Memo by December 3
• What files/methods you will produce
• What inputs and outputs will look like
• Final Project Due last day of class

4
About the Exam

• Total points 114 100
• No real extra credit
• I reduced the point values of some problems
• Grades?
• Class median 89
• Percent (114 Missed) / 114
• Above 90 is an A, etc.

5
Working through the answers

• 1 People tended to forget throws
• A few wrote headers for something not main
• 2 It looks like a few people just guessed
• Prompting for the filename FileWriter/PrintWriter
  for input
• 3, 4 almost always right
• 5 Grammar
• 6-8 forget return type, arg types, arg names
• Extra argument for the return value
• 9 Semicolon double quotes void
• Mark 0 as undefined insist on arguments
• 10 array value passed to constructor
• 12 weird grammar
• 13 weird grammar not a constructor
• 14 void String type

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More answers

• 15 writing a constructor method
• Car type new Car() // type becomes the
  variable name
• 16-8 size on left hand side
• 17 double for size value
• 18 forgetting
• 19 Just needed 0-4
• 20 Starting with 0
• 21-23 using ArrayList operations
• 21 Backwards assignment (several)
• Bad syntax, like an add method
• 23 using or instead of .equals()

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GUIs what well do for graphics

• Arranging windows with interface controls
• Example the bookshelf lab or carpet lab
• Implement with fields to fill in and a compute
  button
• GUIs depend heavily on objects
• A historical thing
• Xerox PARC developed the modern GUI
• They used an OO language to do it

8
Examples of GUI Objects

• A Window (type JFrame)
• Dimensions
• A Title
• Visibility
• Close operation (what to do when closing)
• Window Contents, including
• Labels (type JLabel)
• Contains settable text
• Text Field (type JTextField)
• Contains a readable text field
• Buttons (type JButton)

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Example GUI Objects

• Can you spot JWindow, JTextField, JLabel,
  JButton...

10
Our Friend, JFrame

• What it has dimensions, visibility, a title,
  actions, contents, etc.

11
Creating our own window

• Windows are objects, lets create one
• Import javax.swing.
• JFrame Win new JFrame()
• Win.setTitle(R. Smiths Object Test Window)
• Win.setSize(350, 250)
• Win.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE
  )
• Win.setVisible(true)
• Lets try it

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To Create a Full GUI

• We create customized Window objects
• We take JFrame and customize it
• Customizing through inheritance
• When we inherit, we get the existing object
  features, fields, and methods
• We replace any we want, or add new ones
• We get a normal window plus what we need

13
Creating our own window object

• Its an independent object put in its own file
• Imports javax.swing.
• Class declaration extends JFrame
• Custom Constructor creates the window
• Title setTitle(R. Smiths Object Test Window)
• Size setSize(350, 250)
• Close Button setDefaultCloseOperation
  (JFrame.EXIT_ON_CLOSE)
• Visibility setVisible(true)
• Lets try it

14
GUI from the book KM converter

• Convert kilometers to miles

Text Field
Window Title
Label
Button
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Features

• Label describing what to do
• Text field for the amount to convert
• Button to run the conversion
• Option add a label to hold the answer
• For now, it wont do anything

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Implementation

• We create a special converter window type
• We create objects for each GUI element
• We attach the objects to the window object

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Lab 18 GUI for bookshelf calculation

• Features of the GUI
• A label describing how to use it
• Two text fields to collect the data
• A button to do the calculation
• Another label for outputs and error messages

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Thats it.

• Questions?
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