GUI

Question 1

AWT

Answer 1

Abstract Window Toolkit

Question 2

Swing packages

Answer 2

improved version of AWT

Question 3

event driven programming

Answer 3

programming style based on a
signal-and-response approach.
● Flow of the program determined by events - user actions (mouse clicks, key presses).
● Dominant paradigm used in GUIs and many web applications.

Question 4

listener

Answer 4

listener object performs some action in response to the event
GUI components fire events to listeners

Question 5

event handler

Answer 5

Methods of the listener object that specify what happens when events are received.

Question 6

end GUI program

Answer 6

System.exit(0)

Question 7

action listeners

Answer 7

Buttons fire events known as action events, which are handled by listeners known as action listeners.
ActionListener is an interface:
public class className implements ActionListener
public void actionPerformed (ActionEvent e)

action listener receives the action event as the parameter e to its
actionPerformed method (automatically invoked)

When the user fires a button, an action event is sent to the action listener(s) for that button

Question 8

buttons

Answer 8

Buttons fire events known as action events, which are handled by
listeners known as action listeners
action event includes a String instance variable called the action command for the button or menu item.
String can be retrieved with e.getActionCommand( )

Question 9

action command

Answer 9

default value for action command string is the button text.
setActionCommand is used to change the action command for a
component (useful when multiple components have the same default
action command).

Question 10

components

Answer 10

basic elements of GUI. Each component represents a specific way for the user to interact with the GUI

Question 11

containers

Answer 11

holding space for GUI components. They can have components added to them.
Container class descendents - JFrame, Jpanel

Question 12

3 objects to make Swing GUI

Answer 12

1. Containers
2. Components
3. Layout manager to position the components in the container.

Question 13

layout manager

Answer 13

describe how multiple components are to be arranged
position components inside the container
BorderLayout (default)
* FlowLayout
* GridLayout
* To add a layout manager to a JFrame named window:
window.setLayout(new BorderLayout());

Question 14

border layout

Answer 14

has regions -
eg. BorderLayout.NORTH
window.add(label12, BorderLayout.CENTER) ;

Question 15

flow layout

Answer 15

It arranges components one after the other, going from left to
right, in the order in which they are added.
* If it runs out of space, it wraps to the next line

Question 16

grid layout

Answer 16

arranges components in a 2D grid with some number
of rows and columns.
setLayout(new GridLayout(rows, columns));
Each entry is the same size.
● Each component is stretched so that it fills its grid position.
● Items are placed in the grid from left to right, top to bottom

(rows, 0): specified number of rows, as many columns as required!

(rows, columns) : specified number of rows, as many columns as required!

new GridLayout(0, columns) :
specified number of columns , as many rows as required

Question 17

colours

Answer 17

object of the class Color from the java.awt
constants for basic colours
can be defined w/ diff RGB components
integers must be in range 0-255 inclusive
float values must be in range 0.0f -1.0f inclusive
JColorChooser.showDialog(frame, “title”, initColor);

Question 18

typography

Answer 18

The art of arranging letters and text to make it legible, clear, and visually appealing to the reader

Question 19

font

Answer 19

object of the Font class (from java.awt).
The constructor creates a font in a given style and size
Font font1 = new Font(“SansSerif”, Font.PLAIN, SIZE);
new Font(“SansSerif”, Font.BOLD|Font.ITALIC, SIZE);
w/text field- JTextFiled in ; in.setFont(new …)

Question 20

window listeners

Answer 20

handle window-related events
opening, closing, minimising, maximising, deactivating
activating
interface : public class ClassName implements WindowListener

Question 21

icons

Answer 21

small picture
object of the ImageIcon class
based on a digital picture file such as .gif or .jpg
used to convert a picture file to a Swing icon.
picture file must be in same directory as the class in which this code appears.

Question 22

insets

Answer 22

used to specify the size of the
margin in a button or menu item.
arguments given are in pixels

Question 23

scroll bars

Answer 23

dont have firm limit on the
number of lines or the number of characters per line
text is viewed through a view port that shows only part of the text at a time
JScrollPane
text area to be viewed is given as an argument
JTextArea area = new JTextArea(15, 30);
JScrollPane scrolled = new JScrollPane(area)

Question 24

Graphics

Answer 24

Every container and component that can be drawn on screen has an associated Graphics object.
object has data specifying the area of the screen covered by the component/container

Question 25

paint

Answer 25

method that draws the component or container on the screen. is already defined and is called automatically when the component is displayed on the screen takes in graphics object public void paint (Graphics g) arguments specify location, width, and height of the smallest rectangle that can enclose the oval.