Develop Reference

How to move this eye applet or to make it blink?

Please help me how to make this eye move or to make it blink using repaint, thread and implements runnable. I don't know where to place the right codes to make it work. Please help me guys! Thank you!
Here is the code:
import java.awt.*;
import java.applet.*;
public class Pucca extends Applet {
public Pucca(){
setSize(700, 700); }
//paint method
public void paint(Graphics g){
Color white = new Color(255,255,255);
g.setColor(white);
g.fillOval(600, 100, 125, 125); //left white fill eye
g.setColor(Color.BLA­CK);
g.drawOval(600, 100, 125, 125); // left big black line eye
g.setColor(white);
g.fillOval(700, 100, 125, 125); //right white fill eye
g.setColor(Color.BLA­CK);
g.drawOval(700, 100, 125, 125); //right big black line eye
Color blue = new Color(0, 160, 198);
g.setColor(blue);
g.fillOval(635, 130, 51, 51); // left blue fill eye
g.setColor(Color.BLA­CK);
g.drawOval(635, 130, 50, 50); // left black small line eye
g.setColor(blue);
g.fillOval(735, 130, 51, 51); // right blue fill eye
g.setColor(Color.BLA­CK);
g.drawOval(735, 130, 50, 50); // right black small line eye
g.setColor(Color.BLA­CK);
g.fillOval(650, 145, 20, 20); // left black iris
g.setColor(Color.BLA­CK);
g.fillOval(750, 145, 20, 20); // right black iris
}
}

When it comes to animation, everything becomes variable. You also have a lot of repeated code (seriously, if you can paint one eye, you can paint lots).
The first thing you need to is make all the values of the eye as variable as possible.
The follow makes the eye size and position variable and the iris and pupil a scaled value of the eye size, which makes the whole process simpler to animate.
Next, you need an updated loop, which can update the state of the values you want to change. To keep it simple, I've set it up so that the pupil has a variable offset, which is changed over time.
import java.applet.Applet;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Rectangle;
public class Pucca extends Applet {
public Pucca() {
setSize(700, 700);
Thread t = new Thread(new Runnable() {
private int xDelta = -1;
private int yDelta = 0;
private int blinkCount = 0;
#Override
public void run() {
while (true) {
try {
Thread.sleep(40);
} catch (InterruptedException ex) {
}
xOffset += xDelta;
double irisSize = eyeSize.width * irisScale;
double range = ((eyeSize.width - irisSize) / 2);
if (xOffset <= -range) {
xOffset = -(int) range;
xDelta *= -1;
} else if (xOffset >= range) {
xOffset = (int) range;
xDelta *= -1;
}
blinkCount++;
if (blink && blinkCount > 10) {
blink = false;
blinkCount = 0;
} else if (blinkCount > 25) {
blink = true;
blinkCount = 0;
}
repaint();
}
}
});
t.setDaemon(true);
t.start();
}
private boolean blink = false;
private int xOffset, yOffset = 0;
private Dimension eyeSize = new Dimension(125, 125);
private Point left = new Point(20, 20);
private Point right = new Point(left.x + 100, left.y);
private double irisScale = 0.4;
private double pupilScale = 0.16;
//paint method
#Override
public void paint(Graphics g) {
super.paint(g);
paintEye(g, new Rectangle(left, eyeSize));
paintEye(g, new Rectangle(right, eyeSize));
}
protected void paintEye(Graphics g, Rectangle bounds) {
Color white = new Color(255, 255, 255);
if (blink) {
g.setColor(Color.YELLOW);
} else {
g.setColor(white);
}
g.fillOval(bounds.x, bounds.y, bounds.width, bounds.height); //left white fill eye
g.setColor(Color.BLACK);
g.drawOval(bounds.x, bounds.y, bounds.width, bounds.height); // left big black line eye
if (!blink) {
Color blue = new Color(0, 160, 198);
paintEyePartAt(g, bounds, irisScale, blue);
paintEyePartAt(g, bounds, pupilScale, Color.BLACK);
}
}
private void paintEyePartAt(Graphics g, Rectangle bounds, double delta, Color color) {
int width = (int) (bounds.width * delta);
int height = (int) (bounds.height * delta);
g.setColor(color);
g.fillOval(
xOffset + bounds.x + ((bounds.width - width) / 2),
yOffset + bounds.y + ((bounds.height - height) / 2),
width, height); // left blue fill eye
g.setColor(Color.BLACK);
g.drawOval(
xOffset + bounds.x + ((bounds.width - width) / 2),
yOffset + bounds.y + ((bounds.height - height) / 2),
width,
height); // left blue fill eye
}
}
This complicates things, as painting can occur for any number of reasons, many of which you don't have control over or will be notified about, so you should be very careful about where and when you change values.
You should also have a look at Java Plugin support deprecated and Moving to a Plugin-Free Web and Why CS teachers should stop teaching Java applets.
Applets are simply a dead technology and given the inherent complexities involved in using them, you should instead focus you should probably attention towards window based programs.
Personally, I'd start with having a look at Painting in AWT and Swing and Performing Custom Painting

Java Key Events and Timer control

Im almost finished with this car project im working on but cant seem to get the key events to work. I think it has to do with my action listener with my timer but im not sure. When I press the up arrow key the timer delay is supposed to decrease and vice versa for the down arrow key. I have the commands written but they are not registering input. If anyone could give me some pointers I'd appreciate it
Code:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class RaceCar extends JFrame{
public RaceCar(){
add(new CarPic());
}
public static void main(String[] args){
JFrame frame = new RaceCar();
frame.setTitle("Brady Kedge: Race Car");
frame.setSize(300, 150);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public class CarPic extends JPanel implements KeyListener
{
private int x = 0;
private int y = 150;
private int z = 300;
Timer mytimer = new Timer(50, new ActionListener());
public CarPic()
{
mytimer.start();
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
y = getHeight();
z = getWidth();
g.setColor(Color.WHITE);
g.fillRect(0, 0, z, y);
Polygon polygon = new Polygon();
polygon.addPoint(x + 10, y - 20);
polygon.addPoint(x + 20, y - 30);
polygon.addPoint(x + 30, y - 30);
polygon.addPoint(x + 40, y - 20);
if(x < z - 40)
{
g.setColor(Color.BLACK);
g.fillOval(x + 10, y - 10, 10, 10);
g.fillOval(x + 30, y - 10, 10, 10);
g.setColor(Color.BLUE);
g.fillRect(x, y - 20, 50, 10);
g.setColor(Color.BLUE);
g.fillPolygon(polygon);
}
else
x = 0;
}
public void actionPerformed(ActionEvent e){
x+=10;
repaint();
}
#Override
public void keyTyped(KeyEvent k) {
//Fill
}
#Override
public void keyPressed(KeyEvent k) {
int delay = mytimer.getDelay();
if(k.getKeyCode() == KeyEvent.VK_UP)
mytimer.setDelay(delay > 10 ? delay - 10 : 0);
else if(k.getKeyCode() == KeyEvent.VK_DOWN)
mytimer.setDelay(delay < 5000 ? delay + 10 : 5000);
}
#Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
}
}

First of all, you never register a KeyListener with your component (implementing KeyListener isn't enough).
Second of all, KeyListener will only raise KeyEvents if the component it is registered to has focus and is focusable.
A better solution would be to use the key bindings API, which provides you with the means to configure the focus level at which a component will trigger key events.
Also, personally, instead of modifying the Timer delay, I would have use a speed modifier (of type double) which would be percentage of the speed you want. In this way 1 would normal speed, 0.5 half speed and 2 double speed, for example.

Repaint() not repainting a certain object/updating xy coordinates of a shape

Essentially, in this program bugs move around the screen eating food.
The issue that I am having is that graphics "circle" repaints fine and moves around the frame, but none of the bugs are repainted (However they are drawn initially).
I've tested it with console outputs and the x and y coordinates of the bugs do update, but the graphic in the frame does not.
So my question is, why is it the x/y of the circle is updated and repainted, but the bugs are not?
(As far as I can see, I'm approaching the task of changing the bugs x/y in the same way as with the circle)
(I've removed some of the things like the world getters and setters, and cut the code down a bit. The actual program has a movebug() method which handles the moving of the bugs in a correct fashion with hit detection.)
public class Run extends JPanel implements ActionListener{
double x, y, velX, velY, newx, newy;
public Timer t;
private static AWorld world1;
ArrayList<Ellipse2D> graphicBugArrayList = new ArrayList<Ellipse2D>();
public Run(){
x = 150;
y = 150;
velX = 2;
velY = 2;
t = new Timer(5, this);
setWorld1(new AWorld());
getWorld1().populatemap();
AWorld.direction directionchecker;
repaint();
t.start();
}
public void paintComponent(Graphics g){
//Creating circle that move
g.setColor(Color.BLACK);
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
Ellipse2D circle = new Ellipse2D.Double(x, y, 10, 10);
//creating and drawing the bugs
for(int i=0; i<world1.getNumberofbugs(); i++)
{
Ellipse2D obscircle = new Ellipse2D.Double(getWorld1().bugArrayList.get(i).getHPosition(), getWorld1().bugArrayList.get(i).getVPosition(), 14, 15);
graphicBugArrayList.add(obscircle);
g2.setPaint(Color.RED);
g2.fill(graphicBugArrayList.get(i));
g2.draw(graphicBugArrayList.get(i));
}
//Drawing the circle that moves
g2.setPaint(Color.BLACK);
g2.draw(circle);
}
public void actionPerformed(ActionEvent arg0) {
//Moving the circle
if(x<0 || x > 500)
{
velX = -velX;
}
if(y<0 || y > 500)
{
velY = -velY;
}
x += velX;
y -= velY;
//Test moving the bugs
getWorld1().bugArrayList.get(i).setHPosition(getWorld1().bugArrayList.get(i).getHPosition()+1);
repaint();
}
}

You never clear your graphicBugArrayList, but only draw the first few elements over and over. Try this in your loop:
for(int i=0; i<world1.getNumberofbugs(); i++)
{
Ellipse2D obscircle = new Ellipse2D.Double(getWorld1().bugArrayList.get(i).getHPosition(), getWorld1().bugArrayList.get(i).getVPosition(), 14, 15);
graphicBugArrayList.add(i, obscircle);
g2.setPaint(Color.RED);
g2.fill(graphicBugArrayList.get(i));
g2.draw(graphicBugArrayList.get(i));
}

How to alternate speed using an array of integers for javax swing timer

I am attempting to simulate rain falling using fixed line lengths with randomly generated x coordinates. I have got the random x coordinates working but I want lines to have different falling speeds as well once they are repainted onto the window. I am using the javax swing timer and the java Random to generate integers to pass into my "speed" array as indexes. The speed however does not change. It remains the same and is way too fast.
public class rain extends JPanel implements ActionListener {
int i = 0;
int[] speed = {5, 10, 15, 20, 25, 30, 35, 40, 45, 50};
double[] x = {10, 202, 330, 140, 250, 160, 470, 180, 290, 510};
double y1 = 10, y2 = 20;
double down = 1;
Random random = new Random();
//Timer t = new Timer(speed[i], this);
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D l = (Graphics2D) g;
Line2D line = new Line2D.Double(x[i], y1, x[i], y2);
l.setColor(Color.blue);
l.draw(line);
Timer t = new Timer(speed[i], this);
t.start();
}
public void actionPerformed(ActionEvent e) {
if (y2 < 380) {
y1 += down;
y2 += down;
}else{
y1 = 10;
y2 = 20;
i = random.nextInt(10);
}
repaint();
}

You start a new Timer each time your panel is repainted, and all the previous ones are still running. You should change your algorithm to use a unique timer, and compute the new y based on the previous one and on the current speed.
For example, the time would repaint every 40 milliseconds. If the speed is N, the new y would be the previous one + (N * down)

Decreasing a Filled Rectangle's height from top

I am using a paintComponent Class in a project of mine, and I am currently wondering how I can decrease the size of the rectangle from the top making it's way downwards.
This is the part of the code:
public Battery(){
super();
firstTime = true;
f = new Font("Helvetica", Font.BOLD, 14);
m = Toolkit.getDefaultToolkit().getFontMetrics(f);
}
public void paintComponent(Graphics g){
if(firstTime){
firstTime = false;
batteryLevel = 1 + this.getHeight();
decr = batteryLevel / 20;
}else{
g.setColor(Color.RED);
g.fillRect(1, 0, this.getWidth(), this.getHeight());
g.setColor(Color.GREEN);
g.fillRect(1, 0, this.getWidth(), batteryLevel);
g.setColor(Color.BLACK);
g.setFont(f);
g.drawString("TEST", (getWidth() - m.stringWidth("TEST")) / 2 , this.getHeight() / 2);
}
}
public void decreaseBatteryLevel(){
batteryLevel -= decr;
this.repaint();
}
PS. Sorry if I did something wrong, I'm new to this forum.

As you want the visible battery level to descend you will want to increase your Y co-ordinate in relation to the value of batteryLevel. You could use:
g.fillRect(1, getHeight() - batteryLevel, getWidth(), batteryLevel);

Instead
g.fillRect(1, 0, this.getWidth(), batteryLevel);
Do
g.fillRect(1, batteryLevel, this.getWidth(), getHeight() - batteryLevel);
Also maybe repaint(50L) instead of repaint().
If your question meant: how to animate a change in the battery level.
Use a javax.swing.Timer:
int toPaintBatteryLevel = batteryLevel;
// In the paintComponent paint upto toPaintBatteryLevel.
Timer timer = new Timer(100, new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (toPaintBatteryLevl == batteryLevel) {
return;
}
if (toPaintBatteryLevl > batteryLevel) {
--toPaintBatteryLevel; // Animate slowly
} else {
toPaintBatteryLevel = batteryLevel; // Change immediately
}
repaint(50L);
};
});
timer.start();
For ease of coding, there is a permanent timer. And externally one changes the batteryLevel,
and the time determines the toPaintBatteryLevel, which paintComponent uses to paint.