Computer Science 11 - Unit 4 (GUI)

Constructor

Has same name as class,

is used to initialize variables, JFrame, objects, timers, etc

does NOT have a return type

Method

A method in Java is used to perform a specific task or action within a program.

Helps organize and debug code

it HAS a return type

Method header

access level, return type, method name, args/parameters being passed in

Overloading constructors

When you have the same name within same class but the args are different

What's being passed in is different

it allows a class to provide multiple ways of initializing objects, accommodating different scenarios and enhancing code flexibility

How to make a font object

Font f = new Font("Arial", Font.PLAIN, 18);

g2.setFont(f);

g2.setColor(Color.BLUE);

g2.drawString("Hello", 0, 0);

Setting up timer

*needs to be imported from SWING package

Timer t;

t = new Timer(1000, this);

t.start();

KeyListener: Methods

KeyTyped(KeyEvent e)

KeyPressed(KeyEvent e)

KeyReleased(KeyEvent e)

KeyListener: needed to SETUP keyboard input

setLayout(null);

addKeyListener(this):

setFocusable(true);

requestFocus();

KeyListener: how to detect a key (spacebar)

if (e.getKeySource() == KeyEvent.VK_SPACE)

MouseListener: The 5 methods

MouseClicked(MouseEvent e)

MousePressed(MouseEvent e)

MouseReleased(MouseEvent e)

MouseEntered(MouseEvent e)

MouseExited(MouseEvent e)

MouseMotionListener: The 2 Methods

MouseMoved(MouseEvent e)

MouseDragged(MouseEvent e)

Mouse/Motion Listener: needed to SETUP mouse input

addMouseListener(this); //ONLY IF USED)

addMouseMotionListener(this); //ONLY IF USED)

setFocusable(true);

requestFocus();

To center a JOptionPane

put "null" in the first parent component

Collision

when 2 image MASKS collide

uses "intersects" method & returns boolean

one of them has to be a rectangle mask to be true

Storing images in array

ImageIcon[] Images = new ImageIcon[1];

Images[0] = new ImageIcon("name1.png");

What is an object

An instance of a class

Used to represent entities in a program

Accessor methods

"get" methods

To return SOMETHING usually a class variable, back to us

Mutator methods

"set" methods

To change something about the class variable

how to set RGB color (for blue)

Color blue = new Color(0, 0, 255);

UML: acronym

Unified Modeling Language

UML Symbols:

"-" is private

"+" is public

"#" is protected

Graphics2D: Drawing masks

mask = new Rectangle2D.Double(playerX, playerY, img.getIconWidth(), img.getIconHeight())

Graphics2D: Drawing images

g2.drawImage(ImageIcon.getImage(), xPos, yPos, this);

The 5 JOptionPane Icons

ERROR_MESSAGE

INFORMATION_MESSAGE

WARNING_MESSAGE

QUESTION _MESSAGE

PLAIN_MESSAGE

Dragging an image

use "MouseDragged(MouseEvent e)" method

check if user clicks inside image then update the image's x and y position to the mouse's position as its being dragged.

How to determine mouse's position

mouseX = e.getX();

mouseY = e.getY();

customized images to JOptionPane (message, input, option):

JOptionPane.showMessageDialog(null, "Text", " Title", Message Type, ImageIcon);

JOptionPane.showInputDialog (null, "age:", "Dialog", JOptionPane. PLAIN_MESSAGE, ImageIcon, null, null));

JOptionPane.showOptionDialog (null, "Question", " Title", Message Type, 0, ImageIcon, null, null);

Get input from JOptionPane (string & number)

str = JOptionPane.showInputDialog(null, "Text", "Title", JOptionPane.PLAIN_MESSAGE));

age = Integer.parseInt((String) JOptionPane.showInputDialog (null, "age:", "Dialog", JOptionPane. PLAIN_MESSAGE));