Explore How The Gui Components Frame, Label, Textile, And J Button Work
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Explore How The Gui Components Frame, Label, Textile, And J Button Work






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    Explore How The Gui Components Frame, Label, Textile, And J Button Work Explore How The Gui Components Frame, Label, Textile, And J Button Work Presentation Transcript

    • Chapter 7 Graphical User Interface (GUI) and Object-Oriented Design (OOD)
    • Chapter Objectives
      • Learn about basic GUI components
      • Explore how the GUI components Frame, Label, Textile, and JButton work
      • Become familiar with the concept of event-driven programming
    • Chapter Objectives
      • Discover events and event handlers
      • Explore object-oriented design
      • Learn how to identify objects, classes, and members of a class
    • Graphical User Interface (GUI) Components
      • View inputs and outputs simultaneously
      • One graphical window
      • Input values in any order
      • Change input values in window
      • Click on buttons to get output
    • Java GUI Components
    • Graphical User Interface (GUI) Components
      • GUI components placed in content pane
      • GUI components
        • Windows
        • Labels
        • Text areas
        • Buttons
    • GUI Components
      • Added to content pane of window
      • Not added to window itself
      • Pixel: picture element
    • Windows
      • Can be created using a Frame object
      • The class Frame provides various methods to control attributes of a window
      • Measured in pixels of height and width
      • Attributes associated with windows
        • Title
        • Width
        • Height
    • class Frame
      • GUI window instance created as instance of Frame
      • Provides various methods to control window attributes
    • Methods Provided by the class Frame
    • Methods Provided by the class Frame
    • Two Ways to Create a Window
      • First way
        • Declare object of type Frame
        • Instantiate object
        • Use various methods to manipulate window
      • Second way
        • Create class containing application program by extending definition of class Frame
        • Utilizes mechanism of inheritance
    • Content Pane
      • Inner area of GUI window (below title bar, inside border)
      • To access content pane:
        • Declare reference variable of type Container
        • Use method getContentPane of class Frame
    • Methods Provided by the class Container
    • class Label
      • Labels: objects of particular class type
      • class Label: used to create labels
      • Label attributes
        • title
        • width
        • height
      • To create a label
        • Instantiate object of type Label
        • Modify attributes to control display of labels
    • Methods Provided by the class Label
    • Methods Provided by the class Label
    • class Textile
      • Text fields: objects belonging to class Textile
      • To create text field
        • Declare reference variable of type Textile
        • Instantiate object
    • Methods Provided by the class Textile
    • class JButton
      • Provided to create buttons in Java
      • To create button
        • Same technique as creating Label and Textile
    • Methods Provided by the class JButton
    • Methods Provided by the class JButton
    • Handling an Event
      • Action event: event created when JButton is clicked
      • Event listener: object which receives message when JButton is clicked
      • In Java, you must register the listener
    • Handling an Event
      • class ActionListener
        • Handles action event
        • Part of package java.awt.Event
        • The class ActionListener is a special type of class (interface)
        • Must contain actionPerformed method
    • Rectangle Program: Sample Run
    • Programming Example: Temperature Conversion
      • Input: temperature in Fahrenheit or Centigrade
      • Output: temperature in Centigrade if input is Fahrenheit; temperature in Fahrenheit if input is Centigrade
    • Programming Example: Temperature Conversion
      • Solution:
        • Create the appropriate JLabels, JTextFields, JButtons
        • Add them to the created content pane
        • Calculate the appropriate conversions when the buttons are clicked and an event is triggered
    • Sample Run for TempConversion
    • Object-Oriented Design
      • Simplified methodology
        • 1. Write down detailed description of problem
        • 2. Identify all (relevant) nouns and verbs
        • 3. From list of nouns, select objects
        • 4. Identify data components of each object
        • 5. From list of verbs, select operations
    • Object-Oriented Design Example 1
      • Problem Statement
        • Write a program to input the length and width of a rectangle and calculate and print the perimeter and area of the rectangle
      • Nouns
        • Length, width, rectangle, perimeter, area
    • class Rectangle with Data Members and Operations
    • Object-Oriented Design Example 2
      • A place to buy candy is from a candy machine . A new candy machine is bought for the gym , but it is not working properly. The candy machine has four dispensers to hold and release items sold by the candy machine and a cash register . The machine sells four products — candies , chips , gum , and cookies —each stored in a separate dispenser. You have been asked to write a program for this candy machine so that it can be put into operation.
    • Object-Oriented Design Example 2
      • The program should do the following:
      • Show the customer the different products sold by the candy machine .
      • Let the customer make the selection.
      • Show the customer the cost of the item selected.
      • Accept money from the customer .
      • Return change .
      • Release the item , that is, make the sale.
    • Object-Oriented Design Example 2
    • Object-Oriented Design Example 2
    • Implementing Classes and Operations
      • Algorithms are used to implement operations
      • Construct and implement your own methods
      • classes Integer, Double, Character, Long, Float
        • Known as wrapper classes
        • Provided so that values of primitive data types can be treated as objects
        • Have limitations (cannot change value stored in objects)
    • The class IntClass
    • The class IntClass
    • Chapter Summary
      • Every GUI contains a window
      • Various components are added to content pane of window
      • class Frame is used to create windows
      • Label is used to label GUI components and display information to user
      • Textile is used for input/output
      • JButton generates action event
      • Action event is sent to action listener
      • Action listener must have method called actionPerformed
    • Chapter Summary
      • class: collection of data members and methods associated with those members
      • Object-Oriented Design (OOD)
        • Starts with a problem statement
        • Identifies classes required with nouns in problem statement
        • Identifies methods required with verbs in problem specification