Develop Reference

Removing flashiness/ shakiness from scrolling text

I have finally made a ticker that functions how I want it to, but the only problem now is that it seems kind of shaky and looks like it is being displayed on an old tv. How do I make it look smoother?
Here is my code:
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Scroll1 extends JPanel{
private int x;
private int x2;
private int y;
private int width;
private String text;
private Font f=(new Font("SansSerif", Font.PLAIN,24));
public Scroll1(int startX)
{
x=Integer.MIN_VALUE;
x2=Integer.MIN_VALUE;
y=150;
text= "We are pleased to announce that Actavis has completed the acquisition of Auden Mckenzie, a dynamic and fast growing company focused on the development, licensing and marketing of generic medicines and proprietary brands in the UK. ";
}
#Override
public void paintComponent(Graphics g)
{
g.setFont(f);
if ( x == Integer.MIN_VALUE ){
width=g.getFontMetrics().stringWidth(text);
x = 0;
}
if ( x2 == Integer.MIN_VALUE ){
x2 = g.getFontMetrics().stringWidth(text);
}
g.setColor(Color.white);
g.fillRect(this.getX(), this.getY(), (int)this.getBounds().getWidth(), (int)this.getBounds().getHeight());
g.setColor(Color.black);
g.drawString(text, x, y);
g.drawString(text, x2, y);
}
public void start() throws InterruptedException{
while(true){
while(x>= (-width)&&x2!=Integer.MIN_VALUE){
x--;
x2--;
y = getHeight()/2;
Thread.sleep(15);
this.
validate();
repaint();
if(x2<=-width)
{
x2=width;
}
}
if(x<-width&&x!=Integer.MIN_VALUE)
{
x=width;
}
}
}
public static void main(String[] args) {
JFrame frame = new JFrame("Scrolling Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Scroll1 scrolling = new Scroll1(-100);
frame.getContentPane().add(scrolling);
frame.setSize(400, 300);
frame.setVisible(true);
try {
scrolling.start();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

Call super.paintComponent before you perform custom painting
Prefer Swing Timer of a Thread, as Swing Timers are triggered within the EDT and you run less risk of having dirty reads between the paintComponent method and the Thread
paintComponent really shouldn't be making decisions about the rendering state, instead it should just paint the current state.
You don't need g.fillRect(this.getX(), this.getY(), (int) this.getBounds().getWidth(), (int) this.getBounds().getHeight());, just set the background color of the panel and allow the painting routines to do their jobs. Painting is done from 0x0, been the top/left corner of the component
There is an issue with your while loop in your start method which doesn't seem to allow it to run (at least in my testing)
Can you help me try to transfer it over to a swing timer or give me a good source to do so?
Can you pay me? ;)
First, getting it to be completely "stagger" free isn't going to be possible, as the process is reliant on the system's capability of keeping up to date with your requests. For example, you really don't need to it be running at > 60fps, seriously, 25fps or even 15fps would be more the suitable for what you are trying to do. You control the speed of the scroll by using the movement delta instead
The following example uses a Swing Timer, as did my previous example, but this example will also create a "continuous" loop, where if the amount of text been displayed is less then the width of the visible area, it will add a "new" message to trail it.
This example would be capable of display multiple different messages of varying lengths but I guess, that's a bonus
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Scroll1 extends JPanel {
private String text;
private Font f = (new Font("SansSerif", Font.PLAIN, 24));
private List<TickerTap> tickerTaps;
public Scroll1(int startX) {
text = "We are pleased to announce that Actavis has completed the acquisition of Auden Mckenzie, a dynamic and fast growing company focused on the development, licensing and marketing of generic medicines and proprietary brands in the UK.";
setFont(f);
setBackground(Color.WHITE);
tickerTaps = new ArrayList<>(4);
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
FontMetrics fm = getFontMetrics(getFont());
if (tickerTaps.isEmpty()) {
tickerTaps.add(new TickerTap(text, getWidth()));
}
TickerTap taps[] = tickerTaps.toArray(new TickerTap[tickerTaps.size()]);
int visibleWidth = 0;
for (TickerTap tap : taps) {
tap.move();
int messageWidth = fm.stringWidth(tap.getMessage());
if (tap.getxPos() <= -messageWidth) {
tickerTaps.remove(tap);
} else {
visibleWidth += tap.getxPos() + messageWidth;
}
}
while (visibleWidth < getWidth()) {
TickerTap last = tickerTaps.get(tickerTaps.size() - 1);
int xPos = last.getxPos() + fm.stringWidth(last.getMessage());
String message = " * " + text;
TickerTap next = new TickerTap(message, xPos);
visibleWidth += next.getxPos() + fm.stringWidth(next.getMessage());
tickerTaps.add(next);
}
repaint();
}
});
timer.start();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
for (TickerTap tap : tickerTaps) {
FontMetrics fm = g2d.getFontMetrics();
int y = ((getHeight() - fm.getHeight()) / 2) + fm.getAscent();
g2d.setColor(Color.black);
g2d.drawString(tap.getMessage(), tap.getxPos(), y);
}
}
public class TickerTap {
private String message;
private int xPos;
public TickerTap(String message, int xPos) {
this.message = message;
this.xPos = xPos;
}
public String getMessage() {
return message;
}
public int getxPos() {
return xPos;
}
public void move() {
xPos -= 2;
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Scrolling Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Scroll1 scrolling = new Scroll1(-100);
frame.getContentPane().add(scrolling);
frame.setSize(400, 300);
frame.setVisible(true);
}
});
}
}
Take a look at How to use Swing Timers for more details. Timer is actually really to understand if you simply think of it like a kind of loop

Welp Mad Programmer you are a boss, thanks for all the help. I running what you had and it didnt work, strange huh? Anyway here is what I got now that seems to be working a whole lot smoother but still a few glitches here and there:
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Scroll2 extends JPanel implements ActionListener{
private int x;
private int x2;
private int y;
private int width;
private String text;
private Font f=(new Font("SansSerif", Font.BOLD,34));
Timer t;
public Scroll2(int startX)
{
x=Integer.MIN_VALUE;
x2=Integer.MIN_VALUE;
y=150;
text= "We are pleased to announce that Actavis has completed the acquisition of Auden Mckenzie, a dynamic and fast growing company focused on the development, licensing and marketing of generic medicines and proprietary brands in the UK. ";
Timer refreshTimer = new javax.swing.Timer(10, this);
refreshTimer.start();
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.setFont(f);
if ( x == Integer.MIN_VALUE ){
width=g.getFontMetrics().stringWidth(text);
x = 0;
}
if ( x2 == Integer.MIN_VALUE ){
x2 = g.getFontMetrics().stringWidth(text);
}
g.setColor(Color.white);
g.fillRect(this.getX(), this.getY(), (int)this.getBounds().getWidth(), (int)this.getBounds().getHeight());
g.setColor(Color.black);
g.drawString(text, x, y);
g.drawString(text, x2, y);
}
public void refresh ()
{
if(x>=(-width)&&x2!=Integer.MIN_VALUE)
{
x--;
x2--;
y = getHeight()/2;
}
if(x2<=-width&&x!=Integer.MIN_VALUE)
{
x2=width;
}
if(x<-width&&x!=Integer.MIN_VALUE)
{
x=width;
}
repaint();
}
public static void main(String[] args) {
JFrame frame = new JFrame("Scrolling Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Scroll2 scrolling = new Scroll2(-100);
frame.getContentPane().add(scrolling);
frame.setSize(400, 300);
frame.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
this.refresh();
}
}

Creating animated text that loops on itself

I'm trying to make a news ticker type thing where a string is entered and inside of a JPanel the text is looped.
I know it moves currently at about 90 pixels a second and that there is about 16 pixels per char in this font. So what I am asking is how I can use this information to make it so that after a timer runs for a certain time, a new animated text is spawned, and how after the 1st animated text leaves the screen completely, how to delete it from the memory.
This is what I got so far, the code is borrowed heavily from here : Java Animate JLabel, So also if you see any unneeded code in there, let me know.
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.util.EnumMap;
import javax.swing.*;
#SuppressWarnings("serial")
public class AnimateExample extends JPanel {
private static final int TIMER_DELAY = 20;
private static final String KEY_DOWN = "key down";
public static final int TRANSLATE_SCALE =2;
private static final Font BG_STRING_FONT = new Font(Font.SANS_SERIF,
Font.BOLD, 32);
private EnumMap<Direction, Boolean> dirMap =
new EnumMap<AnimateExample.Direction, Boolean>(Direction.class);
private BufferedImage image = null;
private int posX = 100;
private int posY = 50;
Timer t;
public AnimateExample() {
for (Direction dir : Direction.values()) {
dirMap.put(dir, Boolean.TRUE);
}
t = new Timer(TIMER_DELAY, new TimerListener());
t.start();
ActionMap actionMap = getActionMap();
for (final Direction dir : Direction.values()) {
actionMap.put(dir.Left + KEY_DOWN, new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
dirMap.put(dir, true);
}
});
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g.setFont(BG_STRING_FONT);
g.setColor(Color.LIGHT_GRAY);
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
String s = "Hi, I'm trying to make a news ticker type thing where a string is entered and inside of a JPanel the text is looped.I know it moves currently at about 90 pixels a second and that there is about 16 pixels per char in this font. So what I am asking is how I can use this information to make it so that after a timer runs for a certain time, a new animated text is spawned, and how after the 1st animated text leaves the screen completely, how to delete it from the memory.";
g.drawString(s, posX, posY);
}
private class TimerListener implements ActionListener {
public void actionPerformed(java.awt.event.ActionEvent e) {
for (Direction dir : Direction.values()) {
if (dirMap.get(dir)) {
posX += dir.getX() * TRANSLATE_SCALE;
posY += dir.getY() * TRANSLATE_SCALE;
}
}
repaint();
if(posX<-500)
{
t.stop();
}
};
}
enum Direction {
Left( KeyEvent.VK_LEFT, -1, 0);
private int keyCode;
private int x;
private int y;
private Direction(int keyCode, int x, int y) {
this.keyCode = keyCode;
this.x = x;
this.y = y;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
private static void createAndShowGui() {
AnimateExample mainPanel = new AnimateExample();
JFrame frame = new JFrame("Animate Example");
frame.setUndecorated(true);
frame.setSize(1600, 900);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(null);
frame.add(mainPanel);
mainPanel.setBounds(new Rectangle(1600,400));
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
EDIT:
I was also thinking that perhaps resetting the X position after a certain amount of time or distance, but the problem with that would be that it would require that the area would be blank for one screen length. If you have a work around for that, it would also be great.

You could check out the Marquee Panel. It uses a different approach than most scrollers. You add actual components to the panel and the components scroll.
This allows you to scroll text or images. You can use labels with HTML so you can have colored text etc. The message will continue to scroll until you manually stop the scrolling.
Currently there is no automatic mechanism for replacing a scrolling message. Although you could easily create a List or Queue of messages. Then when a message has finished scrolling completely you just remove the current message and add a new one.
Following is the section code from the MarqueePanel class you would need to change:
public void actionPerformed(ActionEvent ae)
{
scrollOffset = scrollOffset + scrollAmount;
int width = super.getPreferredSize().width;
if (scrollOffset > width)
{
scrollOffset = isWrap() ? wrapOffset + scrollAmount : - getSize().width;
// add code here to swap component from the List or Queue
}
repaint();
}
Of course you would also need to add a method to the class to add a component to the List or Queue.

Don't worry about the character width, as different fonts can produce variable character widths. Instead use FontMetrics to measure the String width and determine it the xPos <= -stringWidth, this is when the text would be fully off the left hand side of the screen.
You could use a Queue of some kind to manage text, popping of the next one as you need it. This example simply pops the last message onto the end of the queue, so it will keep repeating
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import java.util.Queue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
Queue<String> queue = new LinkedList<>();
queue.add("I have something to say, it's better to burn out then fade away");
queue.add("Banana peels");
queue.add("Don't worry if plan A fails, there are 25 more letters in the alphabet");
queue.add("When the past comes knocking, don't answer. It has nothing new to tell you");
queue.add("I know the voices in my head aren't real..... but sometimes their ideas are just absolutely awesome!");
TickerTapPane pane = new TickerTapPane();
pane.setMessages(queue);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(pane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TickerTapPane extends JPanel {
private Queue<String> queue;
private String message;
private int xPos;
public TickerTapPane() {
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (message == null) {
message = queue.remove();
xPos = getWidth();
}
xPos -= 4;
FontMetrics fm = getFontMetrics(getFont());
int stringWidth = fm.stringWidth(message);
if (xPos <= -stringWidth) {
queue.add(message);
xPos = getWidth();
message = queue.remove();
}
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (message != null) {
Graphics2D g2d = (Graphics2D) g.create();
FontMetrics fm = g2d.getFontMetrics();
int yPos = ((getHeight() - fm.getHeight()) / 2) + fm.getAscent();
g2d.drawString(message, xPos, yPos);
g2d.dispose();
}
}
protected void setMessages(Queue<String> queue) {
this.queue = queue;
}
}
}

Java applet repaint a moving circle

I've just moved over from Pygame so Java 2D in an applet is a little new to me, especially when it comes to repainting the screen. In pygame you can simply do display.fill([1,1,1]) but how do I do this in an applet in Java? I understand the use of repaint() but that doesn't clear the screen - any moving object is not 'removed' from the screen so you just get a long line of painted circles.
Here's my code that I've been testing with:
package circles;
import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.Random;
public class circles extends Applet implements Runnable {
private static final long serialVersionUID = -6945236773451552299L;
static Random r = new Random();
String msg = "Click to play!";
static int w = 800, h = 800;
int[] txtPos = { (w/2)-50,(h/2)-50 };
int[] radiusRange = { 5,25 };
int[] circles;
static int[] posRange;
int x = 0, y = 0;
int radius = 0;
int cursorRadius = 10;
boolean game = false;
public static int[] pos() {
int side = r.nextInt(5-1)+1;
switch(side) {
case 1:
posRange = new int[]{ 1,r.nextInt(w),r.nextInt((h+40)-h)+h,r.nextInt(270-90)+90 };
break;
case 2:
posRange = new int[]{ 2,r.nextInt((w+40)-w)+w,r.nextInt(h),r.nextInt(270-90)+90 };
break;
case 3:
posRange = new int[]{ 3,r.nextInt(w),r.nextInt(40)-40,r.nextInt(180) };
break;
case 4:
posRange = new int[]{ 4,r.nextInt(40)-40,r.nextInt(h),r.nextInt(180) };
break;
}
System.out.println(side);
return posRange;
}
public void start() {
setSize(500,500);
setBackground(Color.BLACK);
new Thread(this).start();
}
public void run() {
}
public void update(Graphics g) {
paint(g);
}
public void paint(Graphics e) {
Graphics2D g = (Graphics2D) e;
if(System.currentTimeMillis()%113==0) {
x+=1;
y+=1;
}
g.setColor(Color.BLUE);
g.fillOval(x,y,20,20);
repaint();
}
}

You need to call super.paint(g); in your paint method, as to not leave paint artifacts.
Never call repaint() from inside the paint method
Don't explicitly call paint, as you do in update(), when you mean to call reapaint()
just update the x and y values from inside the update() method, then call repaint()
You don't need to take a Graphics argument in update()
You need to call update() somewhere repeatedly in a loop, as it updates the x and y and reapint()s
If your class is going to be a Runnable, then you should put some code in the run() method. That's probably where you should have your loop
import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
public class circles extends Applet implements Runnable {
int x = 0, y = 0;
public void start() {
setSize(500, 500);
setBackground(Color.BLACK);
new Thread(this).start();
}
public void run() {
while (true) {
try {
update();
Thread.sleep(50);
} catch (InterruptedException ex) {
}
}
}
public void update() {
x += 5;
y += 6;
repaint();
}
public void paint(Graphics e) {
super.paint(e);
Graphics2D g = (Graphics2D) e;
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
}
Side Notes
Why use Applets in the first place. If you must, why use AWT Applet and not Swing JApplet? Time for an upgrade.
Here's how I'd redo the whole thing in Swing, using a Swing Timer instead of a loop and Thread.sleep, as you should be doing.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Circle extends JPanel{
private static final int D_W = 500;
private static final int D_H = 500;
int x = 0;
int y = 0;
public Circle() {
setBackground(Color.BLACK);
Timer timer = new Timer(50, new ActionListener(){
public void actionPerformed(ActionEvent e) {
x += 5;
y += 5;
repaint();
}
});
timer.start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.add(new Circle());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
See How to use Swing Timers
See Create GUIs with Swing
Here's more advanced example for you to look at and ponder.
UPDATE
"Problem is, that's a JPANEL application. I specifically want to make an applet easily usable on a web page. "
You can still use it. Just use the JPanel. Take out the main method, and instead of Applet, use a JApplet and just add the JPanel to your applet. Easy as that.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.Timer;
public class CircleApplet extends JApplet {
#Override
public void init() {
add(new Circle());
}
public class Circle extends JPanel {
private static final int D_W = 500;
private static final int D_H = 500;
int x = 0;
int y = 0;
public Circle() {
setBackground(Color.BLACK);
Timer timer = new Timer(50, new ActionListener() {
public void actionPerformed(ActionEvent e) {
x += 5;
y += 5;
repaint();
}
});
timer.start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
}
}

How can I scroll more than one object at the same time?

New question was asked after this one, found here.
I'm new to Java, but I am working on a recreation of "Flappy Bird" to learn more about java and the way that graphics are displayed. Any solutions or suggestions to any of my questions is greatly appreciated. Thanks!
Right now, my program makes a random pipe and scrolls it, but I don't need it to keep scrolling when x1-3 = -83 (this is when the pipe will be off of the screen completely and is no longer needed).
Questions
How can I make my Game.class scroll more than one instance of Pipes.class while adding a preset distance between them? I could find out the distance to put between them, but as far as displaying more than one, I'm not sure how to do that. At most, 3 pipes have to be displayed at the same time.
How can I display a panel for the main menu, and then switch to the pipes panel after a start button is pressed?
Classes
Game.java
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Game {
Pipes panel = new Pipes();
public Game() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(panel);
f.setTitle("Pipe Game");
f.setResizable(false);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
Timer timer = new Timer(10, new ActionListener() { //pipe speed
#Override
public void actionPerformed(ActionEvent e) {
panel.move();
}
});
timer.start();
Timer refresh = new Timer(30, new ActionListener() { //refresh rate
#Override
public void actionPerformed(ActionEvent e) {
panel.repaint();
}
});
refresh.start();
}
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Game();
}
});
}
}
Pipes.java
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JPanel;
public class Pipes extends JPanel {
//Declare and initialiaze variables
int x1 = 754; //xVal start
int x2 = 75; //pipe width
//total width is 83
int y1 = -1; //yVal start
int y2 = setHeightVal(); //pipe height
int gap = 130; //gap height
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.clearRect(0,0,750,500); //Clear screen
g.drawRect(x1,y1,x2,y2); //Draw part 1
g.drawRect(x1-3,y2-1,x2+6,25); //Draw part 2
g.drawRect(x1-3,y2+25+gap,x2+6,25); //Draw part 3
g.drawRect(x1,y2+25+gap+25,x2,500-y2-49-gap); //Draw part 4
}
public void move() {
x1--;
}
public int getMyX() { //To determine where the pipe is horizontally
return x1-3;
}
public int getMyY() { //To determine where the pipe is vertically
return y2+25;
}
public int setHeightVal() { //Get a random number and select a preset height
int num = (int)(9*Math.random() + 1);
int val = 0;
if (num == 9)
{
val = 295;
}
else if (num == 8)
{
val = 246;
}
else if (num == 7)
{
val = 216;
}
else if (num == 6)
{
val = 185;
}
else if (num == 5)
{
val = 156;
}
else if (num == 4)
{
val = 125;
}
else if (num == 3)
{
val = 96;
}
else if (num == 2)
{
val = 66;
}
else
{
val = 25;
}
return val;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(751, 501);
}
}

"How can I make my Game.class scroll more than one instance of Pipes.class while adding a preset distance between them? "
Here's some simple logic. You want to use a data structure to hold you pipes. What this data structure will hold is whatever data is required to paint then, like x, y, coordinates. For this task, I prefer just to create a new class with it's own draw method, that I pass the paintComponent's Graphics context to. For example
public class Pipe {
int x;
int y;
public class Pipe(int x, int y) {
this.x = x;
this.y = y;
}
public void drawPipe(Graphics g) {
g.fillRect(x, y, 50, 100);
}
}
Now this is just an example class. The above only draws a rectangle, but this is just to show you what you should be doing.
So next you want to have the data structure to hold three Pipe objects, like an array. I prefer to use a List. You'll want that List in your Pipes class, and add three Pipe object to it. You can specify the x to be anything you like, to keep them the same distance apart
public class Pipes extends JPanel {
List<Pipe> pipes = new ArrayList<Pipe>();
public Pipes() {
pipes.add(new Pipe(50, 100));
pipes.add(new Pipe(150, 100));
pipes.add(new Pipe(250, 100));
}
}
Now in the paintComponent method, all you need to do is loop through them and use its drawPipe method
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for ( Pipe pipe : pipes ){
pipe.drawPipe(g);
}
}
Now you move them all you need to do is move there x positions in the timer, and call repaint. You may also want to check against the x to make sure it doesn't do off the screen, or if you moving them the right, you could put them the the very left then whey go off the screen, like a conveyor belt. So you could do something like this
private static final int X_INC = 5;
...
Timer timer = new Timer(40, new ActionListener(){
public void actionPerformed(ActionEvent e) {
for (Pipe pipe : pipes ){
if (pipe.x >= screenWidth) {
pipe.x = 0;
} else {
pipe.x += X_INC;
}
}
repaint();
}
});
As you can see, what I do is loop through the List and just change all their x coordinates, then repaint(). So you can create your own Pipe class with whatever values you need to paint, and just move them around in the loop.
For the changing of speed, instead of using a hard coded vakue like 10 for the timer, use a variable delay, that you can change like with the click of a button
int delay = 100;
JButton speedUp = new JButton("Speed UP");
JButton slowDown = new JButton("Slow Down");
Timer timer = null;
public Pipes() {
timer = new Timer(delay, new ActionListener(){
...
});
timer.start();
speedUp.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
if (!((delay - 20) < 0)) {
delay -=20;
timer.setDelay(delay);
}
}
});
// do the same for slowDown, but decrease the delay
}
Test this out
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Mario extends JPanel {
private static final int D_W = 800;
private static final int D_H = 300;
private static final int X_INC = 5;
BufferedImage bg;
BufferedImage pipeImg;
List<Pipe> pipes = new ArrayList<>();
int delay = 50;
Timer timer = null;
public Mario() {
try {
bg = ImageIO.read(new URL("http://farm8.staticflickr.com/7341/12338164043_0f68c73fe4_o.png"));
pipeImg = ImageIO.read(new URL("http://farm3.staticflickr.com/2882/12338452484_7c72da0929_o.png"));
} catch (IOException ex) {
Logger.getLogger(Mario.class.getName()).log(Level.SEVERE, null, ex);
}
pipes.add(new Pipe(100, 150, pipeImg));
pipes.add(new Pipe(400, 150, pipeImg));
pipes.add(new Pipe(700, 150, pipeImg));
timer = new Timer(delay, new ActionListener(){
public void actionPerformed(ActionEvent e) {
for (Pipe pipe : pipes) {
if (pipe.x > D_W) {
pipe.x = 0;
} else {
pipe.x += X_INC;
}
}
repaint();
}
});
timer.start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(bg, 0, 0, getWidth(), getHeight(), this);
for (Pipe pipe : pipes) {
pipe.drawPipe(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
public class Pipe {
int x;
int y;
Image pipe;
public Pipe(int x, int y, Image pipe) {
this.x = x;
this.y = y;
this.pipe = pipe;
}
public void drawPipe(Graphics g) {
g.drawImage(pipe, x, y, 75, 150, Mario.this);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("Mario Pipes");
frame.add(new Mario());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

JApplet creates a ball that bounces and gets progressively less high in Java

public class Circle extends JApplet {
public void paint(Graphics g) {
int x=100;
int y=100;
int diameter=50;
int xResize=500;
int yResize=500;
super.paint(g);
resize(xResize,yResize);
g.drawOval(x, y, diameter, diameter);
}
}
So I am trying to create a ball that bounces up and down and progressively gets smaller. I need to use the following code as a class that will set up my next class that will actually carry out the action. I know that I need to set up the current code that I have into constructors, instance variables and methods to create objects from but I can't seem to figure out how to do that.
Also how would I make the drawn image move up and down across the JApplet?

This is a basic example of the idea
Basically, when you press the spacebar, it generates a vertical movement which slows over time till it runs out of energy, it will then fall and rebound until it has run out of "bounce"
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class JumpingSprite {
public static void main(String[] args) {
new JumpingSprite();
}
public JumpingSprite() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestPane extends JPanel {
protected static final int SPRITE_HEIGHT = 10;
protected static final int SPRITE_WIDTH = 10;
private float vDelta; // The vertical detla...
private float rbDelta; // Rebound delta...
private float rbDegDelta; // The amount the rebound is degregated...
private int yPos; // The vertical position...
private float gDelta; // Gravity, how much the vDelta will be reduced by over time...
private Timer engine;
private boolean bounce = false;
public TestPane() {
yPos = getPreferredSize().height - SPRITE_HEIGHT;
vDelta = 0;
gDelta = 0.25f;
// This is how much the re-bound will degrade on each cycle...
rbDegDelta = 2.5f;
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap am = getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), "jump");
am.put("jump", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
// Can only bound when we're actually on the ground...
// You might want to add fudge factor here so that the
// sprite can be within a given number of pixels in order to
// jump again...
if (yPos + SPRITE_HEIGHT == getHeight()) {
vDelta = -8;
rbDelta = vDelta;
bounce = true;
}
}
});
engine = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
int height = getHeight();
// No point if we've not been sized...
if (height > 0) {
// Are we bouncing...
if (bounce) {
// Add the vDelta to the yPos
// vDelta may be postive or negative, allowing
// for both up and down movement...
yPos += vDelta;
// Add the gravity to the vDelta, this will slow down
// the upward movement and speed up the downward movement...
// You may wish to place a max speed to this
vDelta += gDelta;
// If the sprite is not on the ground...
if (yPos + SPRITE_HEIGHT >= height) {
// Seat the sprite on the ground
yPos = height - SPRITE_HEIGHT;
// If the re-bound delta is 0 or more then we've stopped
// bouncing...
if (rbDelta >= 0) {
// Stop bouncing...
bounce = false;
} else {
// Add the re-bound degregation delta to the re-bound delta
rbDelta += rbDegDelta;
// Set the vDelta...
vDelta = rbDelta;
}
}
}
}
repaint();
}
});
engine.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int width = getWidth() - 1;
int xPos = (width - SPRITE_WIDTH) / 2;
g2d.drawOval(xPos, yPos, SPRITE_WIDTH, SPRITE_HEIGHT);
g2d.dispose();
}
}
}
The example introduces concepts of Key Bindings, Swing Timer and basic custom painting