1. CiS 260: App Dev I
Chapter 6:
GUI and OOD

2. GUI Components GUI stands for __________ user interface.
A single user interface is much better than individual input and output windows.
Here are some of the GUI components:
JFrame: window that holds other components
JTextField: area for either input or output
JLabel: text that indicates what the user should do
JButton: component that causes an action
Components are place in the content _____ of the window.
Clicking a button is an _________.

3. Classes and Objects
GUI components are instances (________) of classes.
A class is a category of things that have common attributes and behaviors.
In Java, the attributes and behaviors are called data members (fields) and _________.
A window object from the JFrame class has data members like _______, height, and width, and methods like _________.
In Java, a class is used to
define the fields and methods of a type of object
provide a method to create these objects

4. Inheritance and Constructors
___________ is the ability of one class to inherit the fields and methods of another class.
The keyword ________ is how you implement inheritance in Java.
public class RectangleProgram extends JFrame
The class that inherits is called the _________ and the class which provides the fields and methods is called the _________.
A ___________ is a method in a class that creates an object.
The name of a constructor is the same as the name of the _______.

5. Creating a Simple Window
//Java program to create a simple window.
import javax.swing.*;
public class RectangleProgramOne extends JFrame {
private static final int WIDTH = 400;
private static final int HEIGHT = 300;
public RectangleProgramOne()
setTitle("Area and Perimeter of a Rectangle");
setSize(WIDTH,HEIGHT);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true); }
public static void main( String[] args)
RectangleProgramOne rectProg = new RectangleProgramOne();

6. The Content Pane A content pane is the inner area of a window.
To get access to the content pane, you need to first create a __________ object:
Container pane = getContentPane();
The class Container is in the package _________.
To create a layout (5 rows, 2 columns) for the object pane
Pane.setLayout(new GridLayout(5,2));
You must set the layout before adding ___________.

7. JLabel The following statement declares four JLabel objects
private JLabel lengthL, widthL, areaL, perimeterL;
The following statement creates a JLabel object
lengthL = new JLabel("Enter the length: ", SwingConstants.RIGHT);
The following statement adds a label object to the content pane
pane.add(lengthL);

8. Creating a Window With Labels I
//Java program to create a window and place four labels.
import javax.swing.*;
import java.awt.*;
public class RectangleProgramTwo extends JFrame {
private static final int WIDTH = 400;
private static final int HEIGHT = 300;
private JLabel lengthL, widthL, areaL, perimeterL;
public RectangleProgramTwo()
setTitle("Area and Perimeter of a Rectangle");
lengthL = new JLabel("Enter the length: ",SwingConstants.RIGHT);
widthL = new JLabel("Enter the width: ",SwingConstants.RIGHT);
areaL = new JLabel("Area: ",SwingConstants.RIGHT);
perimeterL = new JLabel("Perimeter: ",SwingConstants.RIGHT);

9. Creating a Window With Labels II
Container pane = getContentPane();
pane.setLayout(new GridLayout(4,1));
pane.add(lengthL);
pane.add(widthL);
pane.add(areaL);
pane.add(perimeterL);
setSize(WIDTH, HEIGHT);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE); }
public static void main(String[] args) {
RectangleProgramTwo rectProg = new RectangleProgramTwo();

10. JTextField The following statement declares four JTextField objects
private JTextField lengthTF, widthTF, areaTF, perimeterTF;
The following statement creates a JTextField object
lengthTF = new JTextField(10);
The following statement adds a label object to the content pane
pane.add(lengthTF);

11. Window With Labels and Text Fields

12. JButton The following statements create two ________ objects
JButton calculateB, exitB;
calculateB = new JButton("Calculate");
exitB = new JButton("Exit");
The following statements add the button objects to the ________ pane
pane.add(calculateB);
pane.add(exitB);
The GridLayout now needs 5 rows, 2 columns
pane.setLayout(new GridLayout(5,2));
Placement of components in the grid is from left to right, then top to bottom.

13. Window w/ Labels, Text Fields, Buttons

14. Handling Events
When a button is clicked, an ActionEvent object is created, which calls the actionPerformed() method of an ActionListener object.
The class ActionListener is called an __________, a class that contains only method declarations, such as actionPerformed().
For each JButton, you must _________ a particular ActionListener object by creating a class to handle the action event.
You must then define the actionPerformed() method within the handler class that you created.

15. Steps To Deploy Button Handlers I
Within the application class, declare an action handler object for a button
CalculateButtonHandler calculateHandler;
After creating the JButton object, create the action handler object
calculateHandler = new CalculateButtonHandler();
Then register (associate) the button handler object with the button
calculateB.addActionListener(calculateHandler);

16. Steps To Deploy Button Handlers II
Create the class that handles the action event
private class CalculateButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent e) {
double width, length, area, perimeter;
length = Double.parseDouble(lengthTF.getText());
width = Double.parseDouble(widthTF.getText());
area = length * width;
perimeter = 2 * (length + width);
areaTF.setText("" + area);
perimeterTF.setText("" + perimeter); }

17. Completed Application (pp. 287-289)

18. More About OO Design (OOD)
Objects
are things that have attributes and __________
are instances of a particular class
A _______ is the definition of the attributes and behaviors of things that belong to it.
A class variable is the software implementation of a class attribute.
A class method is
a method that changes the value of a class variable
the software implementation of a class behavior
_____________ is the act of combining variables and methods in a software class.

19. A Simplified OOD Methodology
Write a detailed description of the problem
Calculate the area and perimeter of a rectangle
Identify all relevant nouns and _______.
Rectangle, area, perimeter
From the nouns, select _________.
Rectangle
Identify the significant attributes of the objects.
Length, width
From the verbs, select the __________.
Calculate area, calculate perimeter