I need to make a simple drawing application which is able to draw a line, a rectangle and a circle between 2 user-given points.
The exact application behavior should look like this:
User clicks on a button to enable certain shape drawing i.e. "Line",
Moves his mouse to a JPanel which makes the cursor change to a
crosshair
User clicks two times which draws two points (small circles) and the
selected shape is drawn between the two points
So far this is what I've came up with:
import java.awt.*;
import java.awt.event.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.border.LineBorder;
import javax.swing.AbstractAction;
import javax.swing.Action;
public class MainFrame
{
private boolean readyToDraw = false;
private int clickCount = 0;
private JFrame frame;
private JPanel drawPanel;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainFrame window = new MainFrame();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public MainFrame() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 800, 600);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JPanel buttonPanel = new JPanel();
buttonPanel.setBackground(Color.WHITE);
buttonPanel.setBorder(new LineBorder(new Color(0, 0, 0), 2, true));
buttonPanel.setBounds(10, 11, 100, 85);
frame.getContentPane().add(buttonPanel);
buttonPanel.setLayout(null);
JButton btnLine = new JButton("Line");
btnLine.setBackground(Color.LIGHT_GRAY);
btnLine.setBounds(4, 4, 92, 25);
btnLine.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// Execute when button is pressed
if (readyToDraw == true) {
System.out.println("Let's draw!");
}
else {
}
System.out.println("Line");
}
});
JButton btnRectangle = new JButton("Rectangle");
btnRectangle.setBackground(Color.LIGHT_GRAY);
btnRectangle.setBounds(4, 30, 92, 25);
btnRectangle.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// Execute when button is pressed
if (readyToDraw == true) {
System.out.println("Let's draw!");
}
else {
}
System.out.println("Rectangle");
}
});
JButton btnCircle = new JButton("Circle");
btnCircle.setBackground(Color.LIGHT_GRAY);
btnCircle.setBounds(4, 56, 92, 25);
btnCircle.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// Execute when button is pressed
if (readyToDraw == true) {
System.out.println("Let's draw!");
}
else {
}
System.out.println("Circle");
}
});
buttonPanel.add(btnLine);
buttonPanel.add(btnRectangle);
buttonPanel.add(btnCircle);
}
#SuppressWarnings("serial")
private class Paint extends JPanel implements MouseListener{
drawPanel = new JPanel();
drawPanel.setBackground(Color.WHITE);
drawPanel.setBounds(120, 11, 664, 550);
frame.getContentPane().add(drawPanel);
this.addMouseListener(new MouseListener());
#Override
public void mouseEntered(MouseEvent arg0) {
Cursor dotCursor = new Cursor(Cursor.CROSSHAIR_CURSOR);
drawPanel.setCursor(dotCursor);
}
#Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
public void mouseClicked(MouseEvent e) {
int x1 = 0;
int y1 = 0;
int x2 = 0;
int y2 = 0;
if (clickCount == 0) {
x1 = e.getX();
y1 = e.getY();
clickCount++;
} else if (clickCount == 1) {
x2 = e.getX();
y2 = e.getY();
clickCount++;
readyToDraw = true;
} else {
clickCount = 0;
readyToDraw = false;
}
System.out.println(x1 + " " + y1 + " " + clickCount + " " + x2 + " "
+ y2 + readyToDraw);
}
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
}
This contains some errors which I am unable to resolve. What I need is an explanation of how to make my application to be able to at least draw a line.
In your Paint class, you seem to trying to execute functionality outside of the context of a method or constructor...
private class Paint extends JPanel implements MouseListener {
// Undefined variable...
drawPanel = new JPanel();
// Executing functionality outside of a method or constructor
drawPanel.setBackground (Color.WHITE);
drawPanel.setBounds (
120, 11, 664, 550);
frame.getContentPane ()
.add(drawPanel);
this.addMouseListener(
new MouseListener());
So, you could do something like...
private class Paint extends JPanel implements MouseListener {
private JPanel drawPanel = new JPanel();
public Paint() {
drawPanel.setBackground(Color.WHITE);
drawPanel.setBounds(
120, 11, 664, 550);
frame.getContentPane()
.add(drawPanel);
this.addMouseListener(
new MouseListener());
}
But that will end up with an error on the this.addMouseListener call, because MouseListener is an interface and needs to be implemented before it can be used, but guess what, you can just do this.addMouseListener(this);
That takes care of compiler errors, but there are a bunch of logic errors...
You seem to create an instance of a JPanel, within a JPanel class (drawPanel in JPanel) and then add this child panel (drawPanel) to the frame directly!? That seems like a complete waste of time and, generally speaking, is simply bad design...
However, you then add a MouseListener to the Paint panel and then try and use it to update the drawPanel....????
Simply speaking, you don't need drawPanel, just get rid of it and use the Paint panel directly (but don't add it to the frame from within the constructor of Paint, Paint shouldn't care)
Avoid using null layouts, pixel perfect layouts are an illusion within modern ui design. There are too many factors which affect the individual size of components, none of which you can control. Swing was designed to work with layout managers at the core, discarding these will lead to no end of issues and problems that you will spend more and more time trying to rectify
Related
Im using JPanel and JFrame to create a program that can draw lines and circles. The problem is that my program only redraws the last object added.
I have tried moving around the repaint. For some reason, when I directly draw shapes onto the graphic in paintComponent(), they show up and refresh each frame. However, I have methods inside of paintComponent that pass the graphic variable to elsewhere methods that draw to the graphic object, these are the shapes that do not show up.
Painter Class
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Painter implements ActionListener, MouseListener, MouseMotionListener {
/**
*
*/
Color temp = Color.RED;
// 0 = line, 1 = circle
int object = 0;
PaintingPanel canvas;
Point startPoint = new Point();
Point endPoint = new Point();
Painter() {
//buttons
JButton circleBut = new JButton();
JButton lineBut = new JButton();
//frame
//close operation
//resizes
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
//holder holds the information
JPanel holder = new JPanel();
JPanel leftPanel = new JPanel();
holder.setLayout(new BorderLayout());
leftPanel.setLayout(new GridLayout(3, 1)); // 3 by 1 grid
JPanel northPanel = new JPanel();
northPanel.setLayout(new GridLayout(1, 2)); // 3 by 1 grid
frame.add(holder);
// circle and line buttons
circleBut.setText("Circle");
lineBut.setText("Line");
northPanel.add(circleBut);
northPanel.add(lineBut);
circleBut.setActionCommand("1");
lineBut.setActionCommand("0");
//
holder.add(northPanel, BorderLayout.NORTH);
// red
JButton redPaint = new JButton();
redPaint.setBackground(Color.RED);
redPaint.setOpaque(true);
redPaint.setBorderPainted(false);
leftPanel.add(redPaint);
redPaint.setActionCommand("red");
// green
JButton greenPaint = new JButton();
greenPaint.setBackground(Color.GREEN);
greenPaint.setOpaque(true);
greenPaint.setBorderPainted(false);
leftPanel.add(greenPaint);
greenPaint.setActionCommand("green");
// blue
JButton bluePaint = new JButton();
bluePaint.setBackground(Color.BLUE);
bluePaint.setOpaque(true);
bluePaint.setBorderPainted(false);
leftPanel.add(bluePaint);
bluePaint.setActionCommand("blue");
holder.add(leftPanel, BorderLayout.WEST);
// still need to add painting panel to the CENTER panel
canvas = new PaintingPanel();
holder.add(canvas, BorderLayout.CENTER);
circleBut.addActionListener(this);
lineBut.addActionListener(this);
redPaint.addActionListener(this);
greenPaint.addActionListener(this);
bluePaint.addActionListener(this);
canvas.addMouseListener(this);
//holder.addMouseMotionListener(this);
// still need to add chat panel to the SOUTH panel
frame.setContentPane(holder);
frame.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("red")) {
temp = Color.RED;
System.out.println("received r");
} else if (e.getActionCommand().equals("green")) {
temp = Color.GREEN;
System.out.println("received g");
} else if (e.getActionCommand().equals("blue")) {
temp = Color.BLUE;
System.out.println("received b");
} else if (e.getActionCommand().equals("0")) {
object = 0;
System.out.println("received 0");
} else if (e.getActionCommand().equals("1")) {
object = 1;
System.out.println("received 1");
}
}
#Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseClicked(MouseEvent e) {
}
#Override
public void mousePressed(MouseEvent e) {
startPoint.setLocation(e.getPoint());
}
#Override
public void mouseReleased(MouseEvent e) {
// and this one
endPoint.setLocation(e.getPoint());
if (object == 0) {
canvas.addPrimitive(new Line(startPoint, endPoint, temp));
}
if (object == 1){
canvas.addPrimitive(new Circle(startPoint, endPoint, temp));
}
canvas.repaint();
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
public static void main(String[] args) {
Painter game1 = new Painter();
}
}
PaintingPrimitives:
`
import java.awt.Graphics;
import java.awt.Color;
public abstract class PaintingPrimitive{
Color color;
PaintingPrimitive(Color color) {
this.color = color;
}
// This is an example of the Template Design Pattern
// this is all invariant code
public final void draw(Graphics g) {
g.setColor(color);
drawGeometry(g);
}
public void setColor(Color color) {
this.color = color;
}
protected abstract void drawGeometry(Graphics g);
}
Line Class:
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Color;
public class Line extends PaintingPrimitive{
Point startPoint = new Point();
Point endPoint = new Point();
public Line(Point start, Point end, Color c) {
super(c);
this.startPoint = start;
this.endPoint = end;
}
public void drawGeometry(Graphics g) {
System.out.println("graw geo called");
g.drawLine(startPoint.x, startPoint.y, endPoint.x, endPoint.y);
}
#Override
public String toString() {
return "Line";
}
}
Painting Panel:
import java.util.ArrayList;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.Color;
public class PaintingPanel extends JPanel {
ArrayList<PaintingPrimitive> primitives = new ArrayList<PaintingPrimitive>();
PaintingPanel() {
setBackground(Color.WHITE);
}
public void addPrimitive(PaintingPrimitive obj) {
primitives.add(obj);
this.repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// i'm confident that this is not painting to the right graphics
for (PaintingPrimitive shape : primitives) {
//g.dispose();
//this line works. this line is drawn each time its updated.
g.drawLine(0,0,100,100);
shape.draw(g);
}
}
}
`
Okay, that was weird, until it wasn't. Your problem basic centers around...
public void mousePressed(MouseEvent e) {
startPoint.setLocation(e.getPoint());
}
#Override
public void mouseReleased(MouseEvent e) {
// and this one
endPoint.setLocation(e.getPoint());
if (object == 0) {
canvas.addPrimitive(new Line(startPoint, endPoint, temp));
}
You create a single instance of startPoint and endPoint and simply update the location of each Point. You then pass these to each primitive you create. This means that each primitive is using the SAME instance of startPoint and endPoint. So, each time you call setLocation ALL the primitives are been updated.
Instead, do something more like...
#Override
public void mousePressed(MouseEvent e) {
startPoint = new Point(e.getPoint());
}
#Override
public void mouseReleased(MouseEvent e) {
// and this one
endPoint = new Point(e.getPoint());
And because I'm paranoid and don't trust any one, I'd probably also do...
public class Line extends PaintingPrimitive {
Point startPoint = new Point();
Point endPoint = new Point();
public Line(Point start, Point end, Color c) {
super(c);
this.startPoint = new Point(start);
this.endPoint = new Point(end);
}
Just to be sure
I am learning Java currently and have been given the assignmnet of finidhing off a program to create the game Conways's life (we started with some code provided to us and must add features etc to this).
I am currently stuck on a menu option for the game. I want it to start off at the menu screen, wherein buttons appear at the top for "Start", "Random", "Load", Save". I have written code so that the program displays these buttons, through a fillRect option in my paint method.
My question is, how do I use the mousePressed method to recognise the cells selected so that I can get an action to occur when they are selected. I been looking at this for a while but can't seem to get this working.
Any suggestion would be a massive help. I have shared my code below. It's a work in progress but I would really like to get this working before continuing on with the other functionality.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.*;
public class ConwaysLife extends JFrame implements Runnable, MouseListener {
// member data
private BufferStrategy strategy;
private Graphics offscreenBuffer;
private boolean gameState[][] = new boolean[40][40];
private boolean isGameInProgress = false;
// constructor
public ConwaysLife () {
//Display the window, centred on the screen
Dimension screensize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
int x = screensize.width/2 - 400;
int y = screensize.height/2 - 400;
setBounds(x, y, 800, 800);
setVisible(true);
this.setTitle("Conway's game of life");
// initialise double-buffering
createBufferStrategy(2);
strategy = getBufferStrategy();
offscreenBuffer = strategy.getDrawGraphics();
// register the Jframe itself to receive mouse events
addMouseListener(this);
// initialise the game state
for (x=0;x<40;x++) {
for (y=0;y<40;y++) {
gameState[x][y]=false;
}
}
// create and start our animation thread
Thread t = new Thread(this);
t.start();
}
// thread's entry point
public void run() {
while ( 1==1 ) {
// 1: sleep for 1/5 sec
try {
Thread.sleep(200);
} catch (InterruptedException e) { }
// 2: animate game objects [nothing yet!]
/*if (isGameInProgress == false) {
this.repaint();
}*/
// 3: force an application repaint
this.repaint();
}
}
// mouse events which must be implemented for MouseListener
public void mousePressed(MouseEvent e) {
while (!isGameInProgress) {
int x = e.getX()/20;
int y = e.getY()/20;
if(x >= 10 && x <= 80 && y >= 40 && y <= 65) {
isGameInProgress = !isGameInProgress;
this.repaint();
}
}
// determine which cell of the gameState array was clicked on
int x = e.getX()/20;
int y = e.getY()/20;
// toggle the state of the cell
gameState[x][y] = !gameState[x][y];
// request an extra repaint, to get immediate visual feedback
this.repaint();
}
public void mouseReleased(MouseEvent e) { }
public void mouseEntered(MouseEvent e) { }
public void mouseExited(MouseEvent e) { }
public void mouseClicked(MouseEvent e) { }
//
// application's paint method
public void paint(Graphics g) {
Font font = new Font("Veranda", Font.BOLD, 20);
g = offscreenBuffer; // draw to off screen buffer
// clear the canvas with a big black rectangle
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 800);
/*look to add a while game in progress loop here!!!*/
// draw menu options
if(!isGameInProgress) {
g.setColor(Color.green);
g.fillRect(10, 40, 70, 25);
g.fillRect(100, 40, 100, 25);
g.fillRect(300, 40, 170, 25);
g.setColor(Color.BLACK);
g.setFont(font);
g.drawString("Start", 15, 60);
g.drawString("Random", 105, 60);
g.drawString("Load", 305, 60);
g.drawString("Save", 395, 60);
}
// redraw all game objects
g.setColor(Color.WHITE);
for (int x=0;x<40;x++) {
for (int y=0;y<40;y++) {
if (gameState[x][y]) {
g.fillRect(x*20, y*20, 20, 20);
}
}
}
// flip the buffers
strategy.show();
}
// application entry point
public static void main(String[] args) {
ConwaysLife w = new ConwaysLife();
}
}
You're not going to like the answer, but it's the "correct" way to approach the problem.
What you need to understand is, Swing/AWT is using a "passive" rendering workflow and BufferStrategy is using a "active" rendering workflow, these are incompatible with each other.
As a general rule, you should not be overriding paint of top level containers like JFrame, this is going to end in no end of issues. Instead, you should be starting with something like JPanel and overriding it's paintComponent method instead.
Having said that, there's a "simpler" solution available to you. CardLayout. This will allow you to seperate the workflows of the menu from the game and resolve the issue between Swing/AWT and BufferStrategy
For example...
import java.awt.Canvas;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferStrategy;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
enum View {
MENU, GAME;
}
private CardLayout cardLayout = new CardLayout();
private GamePane gamePane;
public MainPane() {
setLayout(cardLayout);
gamePane = new GamePane();
add(new MenuPane(new MenuPane.Observer() {
#Override
public void startNewGame() {
showGame();
}
#Override
public void randomGame() {
}
#Override
public void loadGame() {
}
#Override
public void saveGame() {
}
}), View.MENU);
add(gamePane, View.GAME);
}
protected void add(Component compent, View view) {
add(compent, view.name());
}
protected void showGame() {
show(View.GAME);
gamePane.start();
}
protected void showMenu() {
gamePane.stop();
show(View.MENU);
}
protected void show(View view) {
cardLayout.show(this, view.name());
}
}
public class MenuPane extends JPanel {
public interface Observer {
public void startNewGame();
public void randomGame();
public void loadGame();
public void saveGame();
}
private Observer observer;
public MenuPane(Observer observer) {
this.observer = observer;
JButton startButton = new JButton("Start");
JButton randomButton = new JButton("Random");
JButton loadButton = new JButton("Load");
JButton saveButton = new JButton("Save");
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.ipadx = 10;
gbc.ipady = 10;
gbc.insets = new Insets(8, 8, 8, 8);
gbc.weightx = GridBagConstraints.REMAINDER;
add(startButton, gbc);
add(randomButton, gbc);
add(loadButton, gbc);
add(saveButton, gbc);
startButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.startNewGame();
}
});
randomButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.randomGame();
}
});
loadButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.loadGame();
}
});
saveButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.saveGame();
}
});
}
}
public class GamePane extends Canvas {
private Thread thread;
private volatile boolean isRunning = false;
public GamePane() {
setBackground(Color.BLACK);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void start() {
if (isRunning) {
return;
}
createBufferStrategy(3);
isRunning = true;
thread = new Thread(new Runnable() {
#Override
public void run() {
mainLoop();
}
});
thread.start();
}
protected void stop() {
if (!isRunning || thread == null) {
return;
}
isRunning = false;
try {
thread.join();
} catch (InterruptedException ex) {
}
thread = null;
}
protected void mainLoop() {
try {
while (isRunning) {
render();
Thread.sleep(16);
}
} catch (InterruptedException ex) {
}
}
protected void render() {
BufferStrategy strategy = getBufferStrategy();
if (strategy == null) {
return;
}
// Render single frame
do {
// The following loop ensures that the contents of the drawing buffer
// are consistent in case the underlying surface was recreated
do {
// Get a new graphics context every time through the loop
// to make sure the strategy is validated
Graphics graphics = strategy.getDrawGraphics();
FontMetrics fm = graphics.getFontMetrics();
String text = "All your game are belong to us";
int x = (getWidth() - fm.stringWidth(text)) / 2;
int y = (getHeight() - fm.getHeight()) / 2;
graphics.setColor(Color.WHITE);
graphics.drawString(text, x, y + fm.getAscent());
// Render to graphics
// ...
// Dispose the graphics
graphics.dispose();
// Repeat the rendering if the drawing buffer contents
// were restored
} while (strategy.contentsRestored());
// Display the buffer
strategy.show();
// Repeat the rendering if the drawing buffer was lost
} while (strategy.contentsLost());
}
}
}
I would strongly recommend that you take the time to read through:
Creating a GUI With Swing
A Visual Guide to Layout Managers
Performing Custom Painting
Painting in AWT and Swing
BufferStrategy and BufferCapabilities
JavaDocs for BufferStrategy which demonstrate how the API should be used.
A "fully" BufferStrategy based approach...
Now, if you can't use Swing, "for reasons", you can still achieve a simular concept using "delegation".
Basically this means "delegating" responsibility for performing some workflow to another. In this case, we want to delegate the rendering and the handling of the mouse events.
This allows you to have a dedicated workflow for the menu and a dedicated workflow for the game, without having to try and mix a lot of state.
Why do I keep on insisting on separating these two workflows? Simply, because it makes it MUCH easier to manage and reason about, but also because it supports the Single Responsibility Principle.
The follow example makes use of Renderable interface to define the core functionality that end "render" delegate will need to implement, in this case, it's pretty simple, we want to tell the renderer to "render" it's content on each paint pass and we want to (optionally) delegate mouse clicked events (this could be done via a second interface or even just the MouseListener interface directly, but I've made it a requirement of the Renderable interface for demonstration purposes.
The "basic" solution to your actual question is found through the use of Rectangle#contains(Point).
This basically inspects each "button" Rectangle to determine if the supplied MouseEvent occurs within it's bounds, if it does, we take action.
It is, however, a little more complicated then that, as we need to have the Rectangles built ahead of time, not difficult, but it's state which is actually reliant on the parent, as we need to know the area in which the renderer is been displayed, run the example, you'll see what I mean 😉
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
MainPane mainPane = new MainPane();
JFrame frame = new JFrame();
frame.add(mainPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
mainPane.start();
}
});
}
public interface Renderable {
public void render(Graphics2D g2d, Dimension size);
// We could just extend from MouseListener
// but I don't need all those event handlers
public void mouseClicked(MouseEvent e);
}
public class MainPane extends Canvas {
private Thread thread;
private volatile boolean isRunning = false;
private Renderable currentRenderer;
private MenuRenderer menuRenderer;
private GameRenderer gameRenderer;
public MainPane() {
setBackground(Color.BLACK);
gameRenderer = new GameRenderer();
menuRenderer = new MenuRenderer(new MenuRenderer.Observer() {
#Override
public void startNewGame() {
showGame();
}
#Override
public void randomGame() {
}
#Override
public void loadGame() {
}
#Override
public void saveGame() {
}
});
showMenu();
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
if (currentRenderer == null) {
return;
}
currentRenderer.mouseClicked(e);
}
});
}
protected void showMenu() {
// This may need to tell the game renderer to stop
// or pause
currentRenderer = menuRenderer;
}
protected void showGame() {
currentRenderer = gameRenderer;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void start() {
if (isRunning) {
return;
}
createBufferStrategy(3);
isRunning = true;
thread = new Thread(new Runnable() {
#Override
public void run() {
mainLoop();
}
});
thread.start();
}
protected void stop() {
if (!isRunning || thread == null) {
return;
}
isRunning = false;
try {
thread.join();
} catch (InterruptedException ex) {
}
thread = null;
}
protected void mainLoop() {
try {
while (isRunning) {
render();
Thread.sleep(16);
}
} catch (InterruptedException ex) {
}
}
protected void render() {
BufferStrategy strategy = getBufferStrategy();
if (strategy == null && currentRenderer != null) {
return;
}
// Render single frame
do {
// The following loop ensures that the contents of the drawing buffer
// are consistent in case the underlying surface was recreated
do {
// Get a new graphics context every time through the loop
// to make sure the strategy is validated
Graphics2D g2d = (Graphics2D) strategy.getDrawGraphics();
g2d.setBackground(Color.BLACK);
g2d.fillRect(0, 0, getWidth(), getHeight());
RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON
);
g2d.setRenderingHints(hints);
// Render to graphics
currentRenderer.render(g2d, getSize());
// Dispose the graphics
g2d.dispose();
// Repeat the rendering if the drawing buffer contents
// were restored
} while (strategy.contentsRestored());
// Display the buffer
strategy.show();
// Repeat the rendering if the drawing buffer was lost
} while (strategy.contentsLost());
}
}
public class GameRenderer implements Renderable {
#Override
public void render(Graphics2D g2d, Dimension size) {
FontMetrics fm = g2d.getFontMetrics();
String text = "All your game are belong to us";
int x = (size.width - fm.stringWidth(text)) / 2;
int y = (size.height - fm.getHeight()) / 2;
g2d.setColor(Color.WHITE);
g2d.drawString(text, x, y + fm.getAscent());
}
#Override
public void mouseClicked(MouseEvent e) {
}
}
public class MenuRenderer implements Renderable {
public interface Observer {
public void startNewGame();
public void randomGame();
public void loadGame();
public void saveGame();
}
private Observer observer;
private String[] menuOptions = new String[]{
"New Game",
"Random",
"Load Game",
"Save Game"
};
private Rectangle[] menuBounds;
private int internalPadding = 20;
private int horizontalGap = 16;
public MenuRenderer(Observer observer) {
this.observer = observer;
}
#Override
public void render(Graphics2D g2d, Dimension size) {
if (menuBounds == null) {
createMenus(g2d, size);
}
renderMenus(g2d);
}
protected void createMenus(Graphics2D g2d, Dimension size) {
FontMetrics fm = g2d.getFontMetrics();
int totalHeight = (((fm.getHeight() + internalPadding) + horizontalGap) * menuOptions.length) - horizontalGap;
int buttonHeight = fm.getHeight() + internalPadding;
menuBounds = new Rectangle[menuOptions.length];
int buttonWidth = 0;
for (int index = 0; index < menuOptions.length; index++) {
int width = fm.stringWidth(menuOptions[index]) + internalPadding;
buttonWidth = Math.max(width, buttonWidth);
}
int yPos = (size.height - totalHeight) / 2;
for (int index = 0; index < menuOptions.length; index++) {
int xPos = (size.width - buttonWidth) / 2;
Rectangle menuRectangle = new Rectangle(xPos, yPos, buttonWidth, buttonHeight);
menuBounds[index] = menuRectangle;
yPos += buttonHeight + (horizontalGap / 2);
}
}
protected void renderMenus(Graphics2D g2d) {
for (int index = 0; index < menuOptions.length; index++) {
String text = menuOptions[index];
Rectangle bounds = menuBounds[index];
renderMenu(g2d, text, bounds);
}
}
protected void renderMenu(Graphics2D g2d, String text, Rectangle bounds) {
FontMetrics fm = g2d.getFontMetrics();
int textWidth = fm.stringWidth(text);
int textXPos = (bounds.x + (internalPadding / 2)) + ((bounds.width - internalPadding - textWidth) / 2);
int textYPos = bounds.y + (internalPadding / 2);
RoundRectangle2D buttonBackground = new RoundRectangle2D.Double(bounds.x, bounds.y, bounds.width, bounds.height, 20, 20);
g2d.setColor(Color.BLUE.darker());
g2d.fill(buttonBackground);
g2d.setColor(Color.WHITE);
g2d.drawString(text, textXPos, textYPos + fm.getAscent());
}
#Override
public void mouseClicked(MouseEvent e) {
if (menuBounds == null) {
return;
}
for (int index = 0; index < menuOptions.length; index++) {
if (menuBounds[index].contains(e.getPoint())) {
switch (index) {
case 0:
observer.startNewGame();
break;
case 2:
observer.randomGame();
break;
case 3:
observer.loadGame();
break;
case 4:
observer.saveGame();
break;
}
}
}
}
}
}
I am a bit new to threading, so bear with me. All relevant classes will be below the text in one place for easier reference.
Backstory:
I created a simple pong-like game following this tutorial: http://www.edu4java.com/en/game/game1.html
Everything worked perfectly, then I made modifications to better understand how it all works. In the tutorial, there is a main method from which the animations are played continuously. According to the tutorial author, Thread.sleep(10) "...tells the processor that the thread which is being run must sleep for 10 ms, which allows the processor to execute other threads and in particular the AWT-EventQueue thread which calls the paint method."
Now, my question is this:
(Just for fun and to practice Java,) I have created a "launcher" for all the various small programs and games I make. I have yet to get the pong game to work inside the launcher. Without a main method inside the pong frame, the animation never runs. I left the main method in in the code below, so that it works. How would I go about launching the animation from somewhere other than main?
Here's the code:
The Frame and main method:
package pongGame;
import javax.swing.*;
public class PongMainGUI extends JFrame
{
private static final int WINDOW_WIDTH = 500;
private static final int WINDOW_HEIGHT = 800;
private static AnimationPanel panel;
public PongMainGUI()
{
//This line sets the title, and, since it calls the super constructor, it calls setTitle().
super("Pong!");
panel = new AnimationPanel(this);
//This method simply makes the screen appear in the center of whatever size screen you are using.
setLocationRelativeTo(null);
setSize(WINDOW_WIDTH,WINDOW_HEIGHT);
add(panel);
setVisible(true);
}
public static void main(String args[]) throws InterruptedException
{
new PongMainGUI();
while(true)
{
System.out.println("PongMainGUI");
panel.repaint();
panel.move();
Thread.sleep(10);
}
}
}
The Animation Panel:
package pongGame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.event.MouseInputListener;
#SuppressWarnings("serial")
public class AnimationPanel extends JPanel
{
PongMainGUI frame;
Ball ballClass;
Racquet racquetClass;
boolean bool = false;
public AnimationPanel(PongMainGUI frame)
{
this.frame = frame;
addMouseListener(new MouseListener()
{
#Override
public void mouseClicked(MouseEvent arg0)
{
}
#Override
public void mouseEntered(MouseEvent arg0)
{
}
#Override
public void mouseExited(MouseEvent arg0)
{
}
#Override
public void mousePressed(MouseEvent arg0)
{
}
#Override
public void mouseReleased(MouseEvent arg0)
{
}
});
addMouseMotionListener(new MouseMotionListener()
{
#Override
public void mouseDragged(MouseEvent e)
{
}
#Override
public void mouseMoved(MouseEvent e)
{
}
});
addKeyListener(new KeyListener()
{
#Override
public void keyPressed(KeyEvent e)
{
racquetClass.keyPressed(e);
}
#Override
public void keyReleased(KeyEvent e)
{
racquetClass.keyReleased(e);
}
#Override
public void keyTyped(KeyEvent e)
{
}
});
//This is needed to ensure that the keyboard will register properly and receive focus.
setFocusable(true);
ballClass = new Ball(this);
racquetClass = new Racquet(this);
}
public void move()
{
//ballClass.moveBall();
racquetClass.moveRacquet();
}
#Override
public void paint(Graphics g)
{
System.out.println("AnimationPanel paint method");
//This method clears the panel so it appears as if the circle is moving.
super.paint(g);
//Better version of Graphics.
Graphics2D g2d = (Graphics2D) g;
//This method turns antialiasing on, which cleans up the corners.
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
ballClass.paint(g2d);
racquetClass.paint(g2d);
}
public void gameOver()
{
System.out.println("Game over method");
JOptionPane.showMessageDialog(null, "Game Over", "Game Over", JOptionPane.YES_NO_OPTION);
System.exit(ABORT);
}
}
The Ball "sprite":
package pongGame;
import java.awt.Graphics2D;
import java.awt.Rectangle;
public class Ball
{
int xCoordinate = 0;
int yCoordinate = 0;
//1 = right movement, -1 = left
int xDirection = 1;
int yDirection = 1;
private final static byte ballWidth = 30;
private final static byte ballHeight = 30;
private AnimationPanel panel;
public Ball(AnimationPanel panel)
{
this.panel = panel;
}
public void paint(Graphics2D g2d)
{
//This creates the actual circle with a specified width and height.
//Because super.paint(g) is called at the start, a new circle is created each time.
g2d.fillOval(xCoordinate, yCoordinate, ballWidth, ballHeight);
System.out.println("Ball paint method");
moveBall();
}
//What this method does is add 1 to the x and y coordinates each time it's called. However, getWidth() and getHeight() are used to determine the current panel size, not the frame size.
//Then, whatever the width and/or height is is subtracted so the circle does not completely disappear from view.
public void moveBall()
{
if (xCoordinate + xDirection < 0)
{
xDirection = 1;
}
else if (xCoordinate + xDirection > panel.getWidth() - ballWidth)
{
xDirection = -1;
}
if (yCoordinate + yDirection < 0)
{
yDirection = 1;
}
else if (yCoordinate + yDirection > panel.getHeight() - ballHeight)
{
System.out.println("Ball moveBall method");
panel.gameOver();
}
if (collision() == true)
{
yDirection = -1;
yCoordinate = panel.racquetClass.getPaddleHeight() - ballHeight;
}
xCoordinate = xCoordinate + xDirection;
yCoordinate = yCoordinate + yDirection;
}
public Rectangle getBounds()
{
return new Rectangle(xCoordinate, yCoordinate, ballWidth, ballHeight);
}
private boolean collision()
{
return panel.racquetClass.getBounds().intersects(getBounds());
}
}
And finally, the Racquet "sprite":
package pongGame;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;
public class Racquet
{
private AnimationPanel panel;
private int xCoordinate = 0;
//0 = no movement, 1 is right, -1 is left.
private byte direction = 0;
//All of the following values are in pixels.
private final static byte PADDLE_OFFSET = 100;
private final static byte PADDLE_WIDTH = 120;
private final static byte PADDLE_HEIGHT = 10;
public Racquet(AnimationPanel panel)
{
this.panel = panel;
}
public void moveRacquet()
{
if (xCoordinate + direction > 0 && xCoordinate + direction < panel.getWidth()-60)
xCoordinate = xCoordinate + direction;
}
public void paint(Graphics2D g)
{
g.fillRect(xCoordinate, getPaddleHeight(), PADDLE_WIDTH, PADDLE_HEIGHT);
//move();
}
public void keyReleased(KeyEvent e)
{
direction = 0;
}
public void keyPressed(KeyEvent e)
{
if (e.getKeyCode() == KeyEvent.VK_LEFT)
direction = -1;
if (e.getKeyCode() == KeyEvent.VK_RIGHT)
direction = 1;
}
public Rectangle getBounds()
{
return new Rectangle(xCoordinate, getPaddleHeight(), PADDLE_WIDTH, PADDLE_HEIGHT);
}
public int getPaddleHeight()
{
return panel.getHeight() - PADDLE_OFFSET;
}
}
This may or may not help, but this is the code for the launcher I wanted to use to open the game:
This is the "main menu":
package GUI;
import javax.swing.*;
import painter.MainPainterGUI;
import java.awt.*;
import java.awt.event.*;
/**
* This class serves to create the launcher gui for the program.
* It extends JFrame.
* #author Jackson Murrell
*/
#SuppressWarnings("serial")
public class LauncherGUI extends JFrame implements ActionListener
{
//A couple constants that are used for sizing things.
private final short WINDOW_HEIGHT = 225;
private final short WINDOW_WIDTH = 550;
private final byte BLANK_SPACE = 25;
//Panels to use for adding in components.
JPanel textPanel, buttonPanel, mainPanel;
//Buttons for user input and selection.
JButton calculator, colorChooser, timer, exit, primeNumberTester, game, painter;
//A text label that will be used for giving the user
//instructions on the program.
JLabel textLabel;
//A constructor to create the GUI components when an object of this class is created.
public LauncherGUI()
{
//This call's the parent method's (JFrame) setTitle method.
super("Omni-program");
//These methods set various options for the JFrame.
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setLocationRelativeTo(null);
textPanel = new JPanel();
buttonPanel = new JPanel();
mainPanel = new JPanel();
calculator = new JButton("Calculator");
colorChooser = new JButton("Color Chooser");
timer = new JButton("Timer");
primeNumberTester = new JButton("Prime Number Tester");
game = new JButton("Games");
exit = new JButton("Exit Launcher and Programs");
painter = new JButton("Painter");
calculator.addActionListener(this);
colorChooser.addActionListener(this);
timer.addActionListener(this);
exit.addActionListener(this);
primeNumberTester.addActionListener(this);
game.addActionListener(this);
painter.addActionListener(this);
textLabel = new JLabel("Welcome to the launcher! Click the button for the mini-program you would like to run.", 0);
textPanel.add(Box.createVerticalStrut(BLANK_SPACE));
textPanel.add(textLabel);
buttonPanel.add(calculator);
buttonPanel.add(colorChooser);
buttonPanel.add(timer);
buttonPanel.add(primeNumberTester);
buttonPanel.add(game);
buttonPanel.add(painter);
buttonPanel.add(exit);
mainPanel.setLayout(new GridLayout(2,1));
mainPanel.add(textPanel);
mainPanel.add(buttonPanel);
//mainPanel.add(Box.createVerticalStrut(BLANK_SPACE));
add(mainPanel);
//pack();
//Having this line at the end instead of the top ensures that once everything is added it is all set to be visible.
setVisible(true);
}
//This method is required since ActionListener is implemented.
//It will be used to process user input.
#Override
public void actionPerformed(ActionEvent e)
{
if (e.getSource() == calculator)
{
new CalculatorGUI();
dispose();
}
else if (e.getSource() == colorChooser)
{
new ColorChooserGUI();
dispose();
}
else if(e.getSource() == timer)
{
new TimerGUI();
dispose();
}
else if (e.getSource() == primeNumberTester)
{
new PrimeNumberTesterGUI();
dispose();
}
else if(e.getSource() == exit)
{
System.exit(0);
}
else if(e.getSource() == painter)
{
new MainPainterGUI();
dispose();
}
else if(e.getSource() == game)
{
new GameLauncherGUI();
dispose();
}
}
}
Here's the actual game launcher:
package GUI;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import pongGame.PongMainGUI;
public class GameLauncherGUI extends JFrame implements ActionListener
{
//A couple constants that are used for sizing things.
private final short WINDOW_HEIGHT = 225;
private final short WINDOW_WIDTH = 550;
private JButton adventureGame, pong, back;
private JLabel label;
private JPanel mainPanel, buttonPanel, textPanel;
public GameLauncherGUI()
{
//This call's the parent method's (JFrame) setTitle method.
super("Omni-program");
//These methods set various options for the JFrame.
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setLocationRelativeTo(null);
adventureGame = new JButton("Adventure Game (Broken)");
adventureGame.addActionListener(this);
pong = new JButton("Pong");
pong.addActionListener(this);
back = new JButton("Back");
back.addActionListener(this);
label = new JLabel("Click the button below for the game you wish to play,\nor click back to go to the previous screen.");
mainPanel = new JPanel();
buttonPanel = new JPanel();
textPanel = new JPanel();
textPanel.add(label);
buttonPanel.add(adventureGame);
buttonPanel.add(pong);
buttonPanel.add(back);
mainPanel.add(textPanel);
mainPanel.add(buttonPanel);
add(mainPanel);
//Having this line at the end instead of the top ensures that once everything is added it is all set to be visible.
setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == back)
{
new LauncherGUI();
dispose();
}
else if(e.getSource() == pong)
{
new PongMainGUI();
dispose();
}
}
}
mainis a static method like others, so you can call it from your launcher:
PongMainGUI.main(null); // launch the pong game
However, note that, in order to avoid lots of trouble, Swing components must be created from the Event Dispatch Thread, as shown in this example. So you should wrap the content of your main method inside a Runnable and launch it with SwingUtilities.invokeLater().
However (again), by doing so, your Thread.sleep(10) will run on the EDT, blocking the GUI responsiveness again. Fortunately, Swing thought of that problem and created a utility called javax.swing.Timer that runs tasks periodically on the EDT (without blocking it):
public static void main(String args[])
{
SwingUtilities.invokeLater(new Runnable(){
public void run(){
new PongMainGUI();
Timer timer = new Timer(10, new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println("PongMainGUI");
panel.repaint();
panel.move();
}
});
timer.start();
}
});
}
This main() method will run safely in standalone, or from your launcher.
So this program that I wrote is supposed to draw a circle everytime click on the panel. For some reason I initially have a semicircle in the top right hand corner upon startup, and I can't get it to draw a circle. Can anyone see what's wrong with it? The circle should be 20 px in diameter, drawn with the clicked point at its center.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class QuizActionsInitial extends JFrame {
public JButton redButton = new JButton("red");
public JButton clearButton = new JButton("clear");
boolean isRed = false;
int x1,y1;
boolean clear = false;
CirclePanel myPanel;
public QuizActionsInitial() {
myPanel = new CirclePanel();
add(myPanel, BorderLayout.SOUTH);
JPanel southPanel = new JPanel(new FlowLayout());
clearButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
clear = true;
}
});
myPanel.addMouseListener(new CircleListener());
southPanel.add(redButton);
southPanel.add(clearButton);
add(southPanel, BorderLayout.NORTH);
pack();
setVisible(true);
} // end constructor
public class CirclePanel extends JPanel {
public CirclePanel() {
setPreferredSize(new Dimension(400,300));
setBorder(BorderFactory.createLineBorder(Color.BLUE, 2));
}
public void paintComponent(Graphics gc){
super.paintComponent(gc);
gc.fillOval(x1-10,y1-10,20,20);
}
} // end class CirclePanel
// end class CirclePanel
public class CircleListener extends MouseAdapter{
public void mouseClicked(MouseEvent e){
if (clear = false){
x1 = e.getX();
y1 = e.getY();
}
repaint();
clear = false;
}
}
public static void main(String args[]) {
new QuizActionsInitial();
} // end main
} // end class QuizActionsInitial
int x1,y1; initialise the values to 0, so you it will always draw an initial circle at -10x-10
Trying using a java.awt.Point class instead, and when it's null, don't paint anything...
//int x1,y1;
private Point point;
//...
public void paintComponent(Graphics gc){
super.paintComponent(gc);
if (point != null) {
gc.fillOval(point.x-10,point.y-10,20,20);
}
}
//...
public void mouseClicked(MouseEvent e){
if (!clear){
point = evt.getPoint();
}
clear = false;
repaint();
}
Oh, and if (clear = false){ is an assignment (making clear equal to false, so that the if statement will ALWAYS fail)
I have a screen with say 500 width and 400 height, and I have a vector with a bunch of shapes. let say the vector has 2 different shapes for example. I want the object to randomly pop up from the bottom of the screen reach a certain ascent and then fall back down (similar to game fruit ninja, where the fruits are my shapes).
In my main (view) I have a vector of shapes of which i instantiate the timers, add to array and place them in the buttom of the screen using the translate function. My timer takes in an action listener which basically changes the translate of the shape to move up till ascent and then down, but my problem is that all the shapes start at the same time regardless.
Something like this:
Shape f = new Shape(new Area(new Ellipse2D.Double(0, 50, 50, 50)));
f.translate(0, 400);
f.timer = new Timer( 10 , taskPerformer);
f.timer.start();
vector.add(f);
Shape f2 = new Shape(new Area(new Rectangle2D.Double(0, 50, 50, 50)));
f2.translate(200, 400);
f2.timer = new Timer( 10 , taskPerformer);
f2.timer.setInitialDelay(5000);
f2.timer.start();
vector.add(f2);
and my action listener:
Random generator = new Random();
ActionListener taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//...Perform a task...
for (Shape s : model.getShapes()) {
// Scale object using translate
// once reached ascent drop down
// translate to diffrenet part of the bottom of the screen
// delay its timer
}
update();
//basically repaints
}
};
I'm running into problems that all shapes follow the same timer, and begin to pop up at the same time (no delay) ...
Any suggestions on how to avoid this or if there is a different approach i should try
"I want the object to randomly pop up from the bottom of the screen reach a certain ascent and then fall back down"
See the runnable example below. What I do is pass a radomDelayedStart to the Shape. Every tick of the timer, the randomDelayedStart decreases til it reaches 0, that's when the flag to be drawn in raised. Most of the logic is in the Shape class methods, which are called in the Timers Actionlistener. Everything is done in one Timer. For the ascent, I just used a hard coded 50, but you can also pass a random ascent to the Shape. Let me know if you have any questions. I tried to made the code as clear as possible.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class RandomShape extends JPanel {
private static final int D_HEIGHT = 500;
private static final int D_WIDTH = 400;
private static final int INCREMENT = 8;
private List<Shape> shapes;
private List<Color> colors;
private Timer timer = null;
public RandomShape() {
colors = createColorList();
shapes = createShapeList();
timer = new Timer(30, new ActionListener() {
public void actionPerformed(ActionEvent e) {
for (Shape shape : shapes) {
shape.move();
shape.decreaseDelay();
repaint();
}
}
});
JButton start = new JButton("Start");
start.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
timer.start();
}
});
JButton reset = new JButton("Reset");
reset.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
shapes = createShapeList();
timer.restart();
}
});
JPanel panel = new JPanel();
panel.add(start);
panel.add(reset);
setLayout(new BorderLayout());
add(panel, BorderLayout.PAGE_START);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Shape shape : shapes) {
shape.drawShape(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_WIDTH, D_HEIGHT);
}
private List<Color> createColorList() {
List<Color> list = new ArrayList<>();
list.add(Color.BLUE);
list.add(Color.GREEN);
list.add(Color.ORANGE);
list.add(Color.MAGENTA);
list.add(Color.CYAN);
list.add(Color.PINK);
return list;
}
private List<Shape> createShapeList() {
List<Shape> list = new ArrayList<>();
Random random = new Random();
for (int i = 0; i < 20; i++) {
int randXLoc = random.nextInt(D_WIDTH);
int randomDelayedStart = random.nextInt(100);
int colorIndex = random.nextInt(colors.size());
Color color = colors.get(colorIndex);
list.add(new Shape(randXLoc, randomDelayedStart, color));
}
return list;
}
class Shape {
int randXLoc;
int y = D_HEIGHT;
int randomDelayedStart;
boolean draw = false;
boolean down = false;
Color color;
public Shape(int randXLoc, int randomDelayedStart, Color color) {
this.randXLoc = randXLoc;
this.randomDelayedStart = randomDelayedStart;
this.color = color;
}
public void drawShape(Graphics g) {
if (draw) {
g.setColor(color);
g.fillOval(randXLoc, y, 30, 30);
}
}
public void move() {
if (draw) {
if (y <= 50) {
down = true;
}
if (down) {
y += INCREMENT;
} else {
y -= INCREMENT;
}
}
}
public void decreaseDelay() {
if (randomDelayedStart <= 0) {
draw = true;
} else {
randomDelayedStart -= 1;
}
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.add(new RandomShape());
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}