I am a beginner with Java Programming and I have a problem. I am using a JPanel in a JScrollPane all contained in a JFrame.
I am using paintComponent() method to draw a certain curve and that's done correctly. The problem is that when I scroll through my panel I see that the image is being cleared. I've searched and learned about flickering but I'm not quiet sure yet what it means and whether that's the problem I am having. I did notice also that when repaint is called the image is cleared.
Here is my code, can anyone let me know if I am doing something wrong?
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.QuadCurve2D;
import javax.swing.JFrame;
import java.lang.Math;
import java.util.Vector;
import javax.swing.*;
import javax.swing.border.LineBorder;
public class DrawCurve extends JPanel {
class MyAdjustmentListener implements AdjustmentListener {
public MyAdjustmentListener() {
}
public void adjustmentValueChanged(AdjustmentEvent evt) {
setFocusable(true);
jScroll.setFocusable(false);
//repaint();
//revalidate();
}
}
Graphics gr;
Stroke drawingStroke = new BasicStroke(0.5f);
double x;
int y = 0;
static String seq = "AAGTCGACCTGTAGCTAGATCGGATCATAGCTCGATCCAGAGATT";
QuadCurve2D curve;
char s;
int a = 0;
int c = 0;
int g = 0;
int t = 0;
int af = 0;
int cf = 0;
int gf = 0;
int tf = 0;
int h = 0;
int flag = 0;
final JScrollPane jScroll = new JScrollPane();
final JFrame parFrame;
Vector<Double> xrand = new Vector<Double>();
public DrawCurve() {
super();
parFrame = new JFrame();
parFrame.pack();
jScroll.setFocusable(false);
setFocusable(true);
parFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
this.setBackground(Color.WHITE);
jScroll.setViewportView(this);
jScroll.getHorizontalScrollBar().addAdjustmentListener(new MyAdjustmentListener());
jScroll.getVerticalScrollBar().addAdjustmentListener(new MyAdjustmentListener());
if (checkSequence(seq) == 0) {
jScroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
jScroll.setViewportBorder(new LineBorder(Color.WHITE));
setFocusable(true);
setPreferredSize(new Dimension(1000, 300));
setBackground(Color.magenta);
parFrame.add(jScroll, BorderLayout.CENTER);
parFrame.setSize(600, 320);
parFrame.setVisible(true);
} else {
JOptionPane.showMessageDialog(null, "invalid input", "Warning!", JOptionPane.PLAIN_MESSAGE);
}
}
public int checkSequence(String sequ) {
int f = 0;
for (int i = 0; i < sequ.length(); i++) {
if (sequ.charAt(i) != "A".charAt(0) && sequ.charAt(i) != "C".charAt(0) && sequ.charAt(i) != "G".charAt(0) && sequ.charAt(i) != "T".charAt(0)) {
f = 1;
break;
}
xrand.add(Math.random() * 300 - 200);
}
return f;
}
public void paintComponent(Graphics gr) {
super.paintComponent(gr);
Graphics2D ga = (Graphics2D) gr;
System.out.println("in");
ga.setStroke(drawingStroke);
for (int i = 0; i < seq.length(); i++) {
s = seq.charAt(i);
if (s == "A".charAt(0)) {
ga.setColor(Color.RED);
a = 1;
af = 1;
cf = 0;
gf = 0;
tf = 0;
h = -1;
} else if (s == "C".charAt(0)) {
ga.setColor(Color.YELLOW);
c = 1;
af = 0;
cf = 1;
gf = 0;
tf = 0;
h = -3;
} else if (s == "G".charAt(0)) {
ga.setColor(Color.GREEN);
g = 1;
af = 0;
cf = 0;
gf = 1;
tf = 0;
h = 1;
} else if (s == "T".charAt(0)) {
ga.setColor(Color.BLUE);
t = 1;
af = 0;
cf = 0;
gf = 0;
tf = 1;
h = 3;
} else {
af = 0;
cf = 0;
gf = 0;
tf = 0;
h = 0;
}
x = Math.random() * 300 - 200;
curve = new QuadCurve2D.Double(y, 250 + h, y + 10, xrand.elementAt(i), y + 20, 250 + h);
ga.draw(curve);
if (a == 1 && af == 0) {
ga.setColor(Color.RED);
h = -1;
ga.drawLine(y, 250 + h, y + 20, 250 + h);
}
if (c == 1 && cf == 0) {
ga.setColor(Color.YELLOW);
h = -3;
ga.drawLine(y, 250 + h, y + 20, 250 + h);
}
if (g == 1 && gf == 0) {
ga.setColor(Color.GREEN);
h = 1;
ga.drawLine(y, 250 + h, y + 20, 250 + h);
}
if (t == 1 && tf == 0) {
ga.setColor(Color.BLUE);
h = 3;
ga.drawLine(y, 250 + h, y + 20, 250 + h);
}
y += 20;
}
}
public static void main(String[] args) {
final DrawCurve panel = new DrawCurve();
}
}
I figured out what's wrong with that code, it turned out that in my loop I forgot to initialize where the curve should start every time the paintComponent is called. Adding y=0; at the start of paintComponent would solve it
Related
I created a very simple shooting game utilizing JPanel as shown in the code below. I also wanted to experiment with rotating the game and trying it out. I have one issue, where the game I was able to successfully rotate the game but the dimension seems to cut out, and I have to set each position of the enemy and myself to the rotated position.
I was wondering if there was a way to rotate the result as a whole, instead of simply rotating the shape so that the position of the ship and the missiles would also rotate all at once.
Edited code: added three lives to the player and tried implementing heart image with BufferedImage.
public class game extends JFrame{
public game(){
}
public static void main(String[] args){
new game();
}
public class MyJPanel extends JPanel implements ActionListener, MouseListener,
MouseMotionListener,KeyListener
{
//variables for player
int my_x;
int player_width,player_height;
private int lives = 3;
int heart_width, heart_height;
//variables for player's missiles
int my_missile_x, my_missile_y;
int missile_flag;
public static final int MY_Y = 600;
//variables for enemies' missiles
int e_missile_flag[];
int e_missile_x[];
int e_missile_y[];
int e_missile_move[];
Image image,image2;
Timer timer;
private BufferedImage heart;
public MyJPanel(){
missile_flag = 0;
/*** initialize enemies' info ***/
ImageIcon icon2 = new ImageIcon("enemy.jpg");
image2 = icon2.getImage();
enemy_width = image2.getWidth(this);
enemy_height = image2.getHeight(this);
try {
heart = ImageIO.read(getClass().getResource("heart.jpg"));
}catch(IOException e) {
}
heart_width = heart.getWidth(this);
heart_height = heart.getHeight(this);
n = 14; //number of enemies
enemy_x = new int[n];
enemy_y = new int[n];
enemy_move = new int[n];
enemy_alive = new int[n];
int distance = 40;
e_missile_flag = new int[n];
e_missile_x = new int[n];
e_missile_y = new int[n];
e_missile_move = new int[n];
// place enemies in 7x2
for (int i = 0; i < 7; i++) {
enemy_x[i] = (enemy_width + distance) * i + 50;
enemy_y[i] = 50;
}
for (int i = 7; i < n; i++) {
enemy_x[i] = (enemy_width + distance) * (i - 5) + 50;
enemy_y[i] = 100;
}
for (int i = 0; i < n; i++) {
enemy_alive[i] = 1; //all alive
enemy_move[i] = -10; //moves to left
}
for (int i = 0; i < n; i++) {
e_missile_flag[i] = 0;
e_missile_x[i] = 0;
e_missile_y[i] = 0;
e_missile_move[i] = 7 + n%3;
}
/*** setup system ***/
setBackground(Color.black);
setFocusable(true);
addMouseListener(this);
addMouseMotionListener(this);
addKeyListener(this);
timer = new Timer(50, this);
timer.start();
}
private void updateEnemiesPosition(){
//update enemies' position
Dimension dim = getSize();
for (int i = 0; i < n; i++) {
enemy_x[i] += enemy_move[i];
if ((enemy_x[i] < 0) || (enemy_x[i] > (dim.width - enemy_width))) {
enemy_move[i] = -enemy_move[i];
}
}
}
private void updateMyPosition() {
if(my_x < 0) {
my_x = 800;
}
if(my_x > 800) {
my_x = 0;
}
}
private void activateMyMissile(){
//shoot a missile
if(missile_flag == 0){
my_missile_x = my_x + player_width / 2;
my_missile_y = MY_Y; //MY_Y=400
missile_flag = 1;
}
}
private void updateMyMissile(){
//update missile position if alive
if (missile_flag == 1) {
my_missile_y -= 15;
if (0 > my_missile_y) {
missile_flag = 0;
}
}
}
private void activateEnemiesMissile(){
//activate enemies' missile if enemy is alive and its missile is not alive
for(int i = 0; i < n; i++){
if (enemy_alive[i] == 1 && e_missile_flag[i] == 0) {
e_missile_x[i] = enemy_x[i] + enemy_width/2;
e_missile_y[i] = enemy_y[i];
e_missile_flag[i] = 1;
}
}
}
private void updateEnemiesMissile(){
//update enemies' missile position if alive
Dimension dim = getSize();
for(int i = 0; i < n; i++){
if (e_missile_flag[i] == 1) {
e_missile_y[i] += e_missile_move[i];
if (e_missile_y[i] > dim.height) {
e_missile_flag[i] = 0;
}
}
}
}
private void checkHitToEnemy(){
for(int i = 0; i < n; i++){
if(missile_flag == 1 && enemy_alive[i] == 1){
if(
my_missile_x > enemy_x[i] &&
my_missile_x < (enemy_x[i] + enemy_width) &&
my_missile_y > enemy_y[i] &&
my_missile_y < (enemy_y[i] + enemy_height)
){
//hit
missile_flag = 0;
enemy_alive[i] = 0;
}
}
}
}
private boolean checkClear(){
int cnt = 0;
for(int i = 0; i < n; i++){
if(enemy_alive[i] == 0) cnt++;
}
return (n == cnt);
}
if(lives>0) {
int x = 0;
int y = getHeight()- heart.getHeight();
for(int index = 0; index < lives; index++) {
g.drawImage(heart, x, y, this);
x += heart.getWidth();
}
}
g2d.dispose();
}
public void actionPerformed(ActionEvent e){
if (e.getSource() == timer) {
updateEnemiesPosition();
updateMyPosition();
updateMyMissile();
updateEnemiesMissile();
activateEnemiesMissile();
if(checkHitToPlayer()){
System.out.println("===== Game Over =====");
System.exit(0);
}
checkHitToEnemy();
if(checkClear()){
System.out.println("===== Game Clear =====");
System.exit(0);
}
repaint();
}
}
public void mouseClicked(MouseEvent me)
{ }
public void mousePressed(MouseEvent me)
{
activateMyMissile();
}
public void mouseReleased(MouseEvent me)
{ }
public void mouseExited(MouseEvent me)
{ }
public void mouseEntered(MouseEvent me)
{ }
public void mouseMoved(MouseEvent me)
{ }
public void mouseDragged(MouseEvent me)
{ }
public void keyReleased(KeyEvent e){
}
public void keyTyped(KeyEvent e){
}
}
}
The original size of the component is going to be less then 800x500 (I say less then, because the actual size will be 800x500 - the frame decorations - this is why you should be setting the size of the window directly).
When you rotate it 90 degrees, it becomes (less then) 500x800. So, no, there's no "easy" way to resolve this, without making the game square.
I added...
g2d.setColor(Color.DARK_GRAY);
g2d.fillRect(0, 0, getWidth(), getHeight());
after the rotation, which highlights the issue.
To do this, you should override getPreferredSize of the JPanel and the call pack on the frame. This will ensure that that game canvas is sized to it's preferred size and the window decorations are then packed around it.
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
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.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Lec12 extends JFrame {
public Lec12() {
setTitle("Game Example");
setDefaultCloseOperation(EXIT_ON_CLOSE);
MyJPanel myJPanel = new MyJPanel();
Container c = getContentPane();
c.add(myJPanel);
pack();
setVisible(true);
}
public static void main(String[] args) {
new Lec12();
}
public class MyJPanel extends JPanel implements ActionListener, MouseListener,
MouseMotionListener, KeyListener {
//variables for player
int my_x;
int player_width, player_height;
//variables for enemies
int enemy_width, enemy_height;
int n;
int enemy_x[];
int enemy_y[];
int enemy_move[];
int enemy_alive[];
//variables for player's missiles
int my_missile_x, my_missile_y;
int missile_flag;
public static final int MY_Y = 400;
//variables for enemies' missiles
int e_missile_flag[];
int e_missile_x[];
int e_missile_y[];
int e_missile_move[];
Image image, image2;
Timer timer;
public MyJPanel() {
/**
* * initialize player's info **
*/
my_x = 250;
ImageIcon icon = new ImageIcon("player.jpg");
image = icon.getImage();
player_width = image.getWidth(this);
player_height = image.getHeight(this);
missile_flag = 0;
/**
* * initialize enemies' info **
*/
ImageIcon icon2 = new ImageIcon("enemy.jpg");
image2 = icon2.getImage();
enemy_width = image2.getWidth(this);
enemy_height = image2.getHeight(this);
n = 14; //number of enemies
enemy_x = new int[n];
enemy_y = new int[n];
enemy_move = new int[n];
enemy_alive = new int[n];
int distance = 40;
e_missile_flag = new int[n];
e_missile_x = new int[n];
e_missile_y = new int[n];
e_missile_move = new int[n];
// place enemies in 7x2
for (int i = 0; i < 7; i++) {
enemy_x[i] = (enemy_width + distance) * i + 50;
enemy_y[i] = 50;
}
for (int i = 7; i < n; i++) {
enemy_x[i] = (enemy_width + distance) * (i - 5) + 50;
enemy_y[i] = 100;
}
for (int i = 0; i < n; i++) {
enemy_alive[i] = 1; //all alive
enemy_move[i] = -10; //moves to left
}
for (int i = 0; i < n; i++) {
e_missile_flag[i] = 0;
e_missile_x[i] = 0;
e_missile_y[i] = 0;
e_missile_move[i] = 7 + n % 3;
}
/**
* * setup system **
*/
setBackground(Color.black);
setFocusable(true);
addMouseListener(this);
addMouseMotionListener(this);
addKeyListener(this);
timer = new Timer(50, this);
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
private void updateEnemiesPosition() {
//update enemies' position
Dimension dim = getSize();
for (int i = 0; i < n; i++) {
enemy_x[i] += enemy_move[i];
if ((enemy_x[i] < 0) || (enemy_x[i] > (dim.width - enemy_width))) {
enemy_move[i] = -enemy_move[i];
}
}
}
private void updateMyPosition() {
if (my_x < 0) {
my_x = 800;
}
if (my_x > 800) {
my_x = 0;
}
}
private void activateMyMissile() {
//shoot a missile
if (missile_flag == 0) {
my_missile_x = my_x + player_width / 2;
my_missile_y = MY_Y; //MY_Y=400
missile_flag = 1;
}
}
private void updateMyMissile() {
//update missile position if alive
if (missile_flag == 1) {
my_missile_y -= 15;
if (0 > my_missile_y) {
missile_flag = 0;
}
}
}
private void activateEnemiesMissile() {
//activate enemies' missile if enemy is alive and its missile is not alive
for (int i = 0; i < n; i++) {
if (enemy_alive[i] == 1 && e_missile_flag[i] == 0) {
e_missile_x[i] = enemy_x[i] + enemy_width / 2;
e_missile_y[i] = enemy_y[i];
e_missile_flag[i] = 1;
}
}
}
private void updateEnemiesMissile() {
//update enemies' missile position if alive
Dimension dim = getSize();
for (int i = 0; i < n; i++) {
if (e_missile_flag[i] == 1) {
e_missile_y[i] += e_missile_move[i];
if (e_missile_y[i] > dim.height) {
e_missile_flag[i] = 0;
}
}
}
}
private void checkHitToEnemy() {
for (int i = 0; i < n; i++) {
if (missile_flag == 1 && enemy_alive[i] == 1) {
if (my_missile_x > enemy_x[i]
&& my_missile_x < (enemy_x[i] + enemy_width)
&& my_missile_y > enemy_y[i]
&& my_missile_y < (enemy_y[i] + enemy_height)) {
//hit
missile_flag = 0;
enemy_alive[i] = 0;
}
}
}
}
private boolean checkHitToPlayer() {
for (int i = 0; i < n; i++) {
if (e_missile_flag[i] == 1) {
if (e_missile_x[i] > my_x
&& e_missile_x[i] < (my_x + player_width)
&& e_missile_y[i] > MY_Y
&& e_missile_y[i] < (MY_Y + player_height)) {
e_missile_flag[i] = 0;
return true;
}
}
}
return false;
}
private boolean checkClear() {
int cnt = 0;
for (int i = 0; i < n; i++) {
if (enemy_alive[i] == 0) {
cnt++;
}
}
return (n == cnt);
}
public void paintComponent(Graphics g) {
super.paintComponent(g); //reset graphics
Graphics2D g2d = (Graphics2D) g.create();
System.out.println(getWidth() + "x" + getHeight());
int w2 = getWidth() / 2;
int h2 = getHeight() / 2;
g2d.rotate(-Math.PI / 2, w2, h2);
g2d.setColor(Color.DARK_GRAY);
g2d.fillRect(0, 0, getWidth(), getHeight());
//draw player
g2d.setColor(Color.BLUE);
g2d.fillRect(my_x, 400, 10, 10);
// g.drawImage(image, my_x, 400, this);
//draw enemies
for (int i = 0; i < n; i++) {
if (enemy_alive[i] == 1) {
g2d.setColor(Color.RED);
g2d.fillRect(enemy_x[i], enemy_y[i], 10, 10);
// g.drawImage(image2, enemy_x[i], enemy_y[i], this);
}
}
//draw players missiles
if (missile_flag == 1) {
g2d.setColor(Color.white);
g2d.fillRect(my_missile_x, my_missile_y, 2, 5);
}
//draw enemies' missiles
for (int i = 0; i < n; i++) {
if (e_missile_flag[i] == 1) {
g2d.setColor(Color.white);
g2d.fillRect(e_missile_x[i], e_missile_y[i], 2, 5);
}
}
g2d.dispose();
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == timer) {
updateEnemiesPosition();
updateMyPosition();
updateMyMissile();
updateEnemiesMissile();
activateEnemiesMissile();
if (checkHitToPlayer()) {
System.out.println("===== Game Over =====");
System.exit(0);
}
checkHitToEnemy();
if (checkClear()) {
System.out.println("===== Game Clear =====");
System.exit(0);
}
repaint();
}
}
public void mouseClicked(MouseEvent me) {
}
public void mousePressed(MouseEvent me) {
activateMyMissile();
}
public void mouseReleased(MouseEvent me) {
}
public void mouseExited(MouseEvent me) {
}
public void mouseEntered(MouseEvent me) {
}
public void mouseMoved(MouseEvent me) {
}
public void mouseDragged(MouseEvent me) {
}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
switch (key) {
case KeyEvent.VK_S:
my_x = my_x + 10;
break;
case KeyEvent.VK_W:
my_x = my_x - 10;
break;
case KeyEvent.VK_DOWN:
my_x = my_x + 10;
break;
case KeyEvent.VK_UP:
my_x = my_x - 10;
break;
case KeyEvent.VK_X:
if (missile_flag == 0) {
my_missile_x = my_x + player_width / 2;
my_missile_y = MY_Y;// MY_Y=400
missile_flag = 1;
}
break;
}
}
public void keyReleased(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
}
}
Also, beware, transformations of this nature are accumulative. You should, instead, take a snapshot of the Graphics context and dispose of it once you're done (see the above for an example).
Also, have look at How to Use Key Bindings as it will help resolve the focus issues related to KeyListener
I am currently just messing around with some code and I keep running into an issue. I want to create ten circles and simply have them bounce around the window. I've had a couple of problems (like when I want the circles to bounce off the wall, for some reason the 400,400 window isn't actually that size. I have the circles collide on the right by checking if x + width >= 400, but it bounces outside the screen unless I change the 400 to 380?), but my main issue is that when I create the circles, I want them to be in different locations (so they aren't colliding before they can even move). I am trying to get it so that if a circle is going to be 'inside' another circle then instead create random x and y coordinates again until it isn't inside another circle. But for some reason, if I put r.nextInt() inside the while loop it keeps giving me the same values. Can anyone help?
p.s. I wouldn't mind advice on any other mistakes I have made.
package practicedots;
import java.awt.Dimension;
import java.awt.Graphics;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class PracticeDots extends JPanel {
float dots[][] = new float[10][7];
Random r = new Random();
boolean first = true;
float x = 0;
float y = 0;
float xAccel = 0;
float yAccel = 0;
int wall = 380;
int width = 50;
float radius = 0;
float centreX = 0;
float centreY = 0;
boolean collision;
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new PracticeDots());
f.setPreferredSize(new Dimension(400, 400));
f.setResizable(true);
f.pack();
f.setVisible(true);
}
/**
*
* #return
*/
public float[][] CreateDots() {
if (first == true) {
for (int i = 0; i < 10; i++) {
while(collision == true){
x = r.nextInt(300);
y = r.nextInt(300);
xAccel = r.nextFloat() / 2;
yAccel = r.nextFloat() / 2;
radius = width/2;
centreX = x + radius;
centreY = y + radius;
dots[i][0] = x;
dots[i][1] = y;
dots[i][2] = xAccel;
dots[i][3] = yAccel;
dots[i][4] = radius;
dots[i][5] = centreX;
dots[i][6] = centreY;
bounce();
}
}
first = false;
} else if (first == false) {
for (int i = 0; i < 10; i++) {
dots[i][0] = dots[i][0] + dots[i][2];
dots[i][1] = dots[i][1] + dots[i][3];
if (dots[i][0] >= wall - width) {
dots[i][2] = -dots[i][2];
}
if (dots[i][1] >= wall - 20 - width) {
dots[i][3] = -dots[i][3];
}
if (dots[i][0] < 0) {
dots[i][2] = -dots[i][2];
}
if (dots[i][1] < 0) {
dots[i][3] = -dots[i][3];
}
bounce();
}
}
repaint();
return dots;
}
//(x2-x1)^2 + (y1-y2)^2 <= (r1+r2)^2
public void bounce() {
for (int i = 0; i < 10; i++) {
for (int a = 0; a < 10; a++) {
if (a != i) {
System.out.println((dots[i][0] - dots[a][0])*(dots[i][0] - dots[a][0]) + (dots[i][1] - dots[a][1])*(dots[i][1] - dots[a][1]) <= (dots[i][4] + dots[a][4]) * (dots[i][4] + dots[a][4]));
collision = (dots[i][0] - dots[a][0])*(dots[i][0] - dots[a][0]) + (dots[i][1] - dots[a][1])*(dots[i][1] - dots[a][1]) <= (dots[i][4] + dots[a][4]) * (dots[i][4] + dots[a][4]);
}
}
}
}
/**
*
* #param g
*/
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for (int i = 0; i < 10; i++) {
CreateDots();
g.drawOval((int) dots[i][0], (int) dots[i][1], width, width);
g.fillOval((int) dots[i][0], (int) dots[i][1], width, width);
}
}
}
<!-- end snippet -->
There were a couple of problems:
During bounce you should return the first time you find a collision, otherwise the collision will be set to true, but then could be set back to false on the next iteration in the for-loop.
In the first == true condition, you should initialize collision to true or it will never do the while loop at all. Either that or change it to a do-while.
During paintComponent you should not call CreateDots within the for-loop since it loops over all dots itself. Just call it before.
The code seems to work with these changes (including width of 400 not 380):
import java.awt.Dimension;
import java.awt.Graphics;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class PracticeDots extends JPanel {
float dots[][] = new float[10][7];
Random r = new Random();
boolean first = true;
float x = 0;
float y = 0;
float xAccel = 0;
float yAccel = 0;
int wall = 400;
int width = 50;
float radius = 0;
float centreX = 0;
float centreY = 0;
boolean collision;
public static void main(String[] args) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new PracticeDots());
f.setPreferredSize(new Dimension(400, 400));
f.setResizable(true);
f.pack();
f.setVisible(true);
}
public float[][] CreateDots() {
if (first == true) {
for (int i = 0; i < 10; i++) {
do {
x = r.nextInt(300);
y = r.nextInt(300);
xAccel = r.nextFloat() / 2;
yAccel = r.nextFloat() / 2;
radius = width / 2;
centreX = x + radius;
centreY = y + radius;
dots[i][0] = x;
dots[i][1] = y;
dots[i][2] = xAccel;
dots[i][3] = yAccel;
dots[i][4] = radius;
dots[i][5] = centreX;
dots[i][6] = centreY;
bounce();
} while (collision == true);
}
first = false;
} else {
for (int i = 0; i < 10; i++) {
dots[i][0] = dots[i][0] + dots[i][2];
dots[i][1] = dots[i][1] + dots[i][3];
if (dots[i][0] >= wall - width) {
dots[i][2] = -dots[i][2];
}
if (dots[i][1] >= wall - 20 - width) {
dots[i][3] = -dots[i][3];
}
if (dots[i][0] < 0) {
dots[i][2] = -dots[i][2];
}
if (dots[i][1] < 0) {
dots[i][3] = -dots[i][3];
}
bounce();
}
}
repaint();
return dots;
}
public void bounce() {
collision = false;
for (int i = 0; i < 10; i++) {
for (int a = 0; a < 10; a++) {
if (a != i && !(dots[a][0] == 0 && dots[a][1] == 0)) {
boolean thisCollision = (dots[i][0] - dots[a][0]) * (dots[i][0] - dots[a][0]) + (dots[i][1] - dots[a][1]) * (dots[i][1] - dots[a][1]) <= (dots[i][4] + dots[a][4]) * (dots[i][4] + dots[a][4]);
// System.out.println("collision: "+collision+" i="+i+" a="+a);
if (thisCollision) {
collision = true;
return;
}
}
}
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
CreateDots();
for (int i = 0; i < 10; i++) {
g.drawOval((int) dots[i][0], (int) dots[i][1], width, width);
g.fillOval((int) dots[i][0], (int) dots[i][1], width, width);
}
}
}
I'm here to ask a little help with a problem I've had for many hours.
In practice, I would like to be able to pass the variables 'j' and 'k' through a method in a matrix. The problem lies in passing them, which, without understanding the reason, are not "captured" when they enter the if. In fact, if I try to print 'r' and 'c' before the if, they match. I do not understand where I'm wrong, because the other things inside the if work perfectly, but when I try to print 'r' and 'c' inside the if, they always turn out to be 0.
Buttons creation :
Integer[] x = {10, 70, 130, 190, 250, 310, 370}; Integer[] y = {80, 140, 200, 260, 320, 380};
for (int i = 0, k = 0, j = 0; i < 42; i++, j++) {
if (j % 7 == 0 && i != 0) { j = 0; k++; }
lblCircles[i] = new JLabel(new ImageIcon(this.getClass().getResource("vuoto.png")));
lblCircles[i].setBounds(x[j], y[k], 50, 50);
lblCircles[i].setName("vuota");
lblCircles[i].addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
for (int i = 0; i < 42; i++) {
for (int j = 0; j < 6; j++) {
for (int k = 0; k < 7; k++)
if (e.getSource() == lblCircles[i] && choose == 1) lblClickedPlayer(lblCircles[i], j, k);
}
}
}
});
frame.getContentPane().add(lblCircles[i]);
}
The method :
public void lblClickedPlayer(JLabel lbl, int r, int c) {
if (n == 0 && "vuota".equals(lbl.getName())) {
n = 1;
lbl.setIcon(new ImageIcon(this.getClass().getResource("red.png")));
lbl.setName("piena");
tbl[r][c] = 1;
System.out.println("tbl[" + r + "][" + c + "] = " + tbl[r][c]);
} else if (n == 1 && "vuota".equals(lbl.getName())) {
n = 0;
lbl.setIcon(new ImageIcon(this.getClass().getResource("yellow.png")));
lbl.setName("piena");
tbl[r][c] = 2;
System.out.println("tbl[" + r + "][" + c + "] = " + tbl[r][c]);
}
}
Thanks in advance for the help.
Code for a test :
public class Prova {
public JFrame frame;
public JLabel[] lblCircles = new JLabel[42];
public String hostname;
public Font big = new Font("Comic Sans MS", Font.BOLD, 18);
public Integer[][] tbl = new Integer[6][7];
public int choose = 1, n = 0;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Prova window = new Prova();
window.frame.setVisible(true);
} catch (Exception e) { e.printStackTrace(); }
}
});
}
public Prova() { initialize(); }
private void initialize() {
frame = new JFrame();
baseFrame(frame, 430, 510);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(6, 7));
panel.setBackground(new Color(41, 41, 41));
panel.setBounds(10, 80, 410, 350);
frame.getContentPane().add(panel);
Integer[] x = {10, 70, 130, 190, 250, 310, 370}; Integer[] y = {80, 140, 200, 260, 320, 380};
for (int i = 0, k = 0, j = 0; i < 42; i++, j++) {
if (j % 7 == 0 && i != 0) { j = 0; k++; }
lblCircles[i] = new JLabel("test");
lblCircles[i].setBounds(x[j], y[k], 50, 50);
lblCircles[i].setForeground(Color.RED);
lblCircles[i].setFont(big);
lblCircles[i].setName("vuota");
lblCircles[i].addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
for (int i = 0; i < 42; i++) {
for (int j = 0; j < 6; j++) {
for (int k = 0; k < 7; k++) {
if (e.getSource() == lblCircles[i] && choose == 1) lblClickedPlayer(lblCircles[i], j, k);
}
}
}
}
});
panel.add(lblCircles[i]);
}
}
public void baseFrame(JFrame baseFrame, int width, int height) {
baseFrame.getContentPane().setBackground(new Color(41, 41, 41));
baseFrame.setBounds(100, 100, width, height);
baseFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
baseFrame.getContentPane().setLayout(null);
baseFrame.setUndecorated(true);
baseFrame.setLocationRelativeTo(null);
baseFrame.setResizable(false);
baseFrame.setVisible(true);
baseFrame.setShape(new RoundRectangle2D.Double(0, 0, baseFrame.getWidth(), baseFrame.getHeight(), 30, 30));
}
public void lblClickedPlayer(JLabel lbl, int r, int c) {
if (n == 0 && "vuota".equals(lbl.getName())) {
n = 1;
lbl.setText("ok1");
lbl.setForeground(Color.GREEN);
lbl.setName("piena");
tbl[r][c] = 1;
System.out.println("tbl[" + r + "][" + c + "] = " + tbl[r][c]);
} else if (n == 1 && "vuota".equals(lbl.getName())) {
n = 0;
lbl.setText("ok2");
lbl.setForeground(Color.GREEN);
lbl.setName("piena");
tbl[r][c] = 2;
System.out.println("tbl[" + r + "][" + c + "] = " + tbl[r][c]);
}
}
}
You don't want those inner loops, since i is all you need. You can calculate the row and column from the i value easily by using int division and int remainder
int r = i / COLS;
int c = i % COLS;
For example
public class Prova {
private static final int ROWS = 6;
private static final int COLS = 7;
// ....
lblCircles[i].addMouseListener(new MouseAdapter() {
// better to use mousePressed, not mouseClicked
public void mousePressed(MouseEvent e) {
// no magic numbers such as 42 please.
for (int i = 0; i < lblCircles.length; i++) {
if (e.getSource() == lblCircles[i] && choose == 1) {
myLabelClicked(lblCircles[i], i);
}
}
}
});
and
public void myLabelClicked(JLabel label, int i) {
int r = i / COLS;
int c = i % COLS;
if (n == 0 && "vuota".equals(label.getName())) {
n = 1;
label.setText("ok1");
label.setForeground(Color.GREEN);
label.setName("piena");
tbl[r][c] = 1;
} else {
n = 0;
label.setText("ok2");
label.setForeground(Color.GREEN);
label.setName("piena");
tbl[r][c] = 2;
}
System.out.println("tbl[" + r + "][" + c + "] = " + tbl[r][c]);
}
Side issues:
Yes, much better using layout managers rather than setBounds, and so your second bit of code is better
Avoid magic numbers such as 42 and instead use properties and constants.
In my code above ROWS = 6 and COLS = 7
My MCVE:
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class Prova2 extends JPanel {
private static final int ROWS = 6;
private static final int COLS = 7;
private static final int LBL_EB = 25; // "eb" for empty border
private static final int PNL_EB = 3;
public static final Font BIG = new Font("Comic Sans MS", Font.BOLD, 18);
private static final Color BACKGROUND = new Color(41, 41, 41);
private static final String VUOTA = "vuota";
private JLabel[] lblCircles = new JLabel[ROWS * COLS];
private Integer[][] tbl = new Integer[ROWS][COLS];
private int choose = 1, n = 0;
public Prova2() {
setBorder(BorderFactory.createEmptyBorder(PNL_EB, PNL_EB, PNL_EB, PNL_EB));
setLayout(new GridLayout(ROWS, COLS));
setBackground(BACKGROUND);
for (int i = 0; i < lblCircles.length; i++) {
lblCircles[i] = new JLabel("test");
lblCircles[i].setForeground(Color.RED);
lblCircles[i].setFont(BIG);
lblCircles[i].setBorder(BorderFactory.createEmptyBorder(LBL_EB, LBL_EB, LBL_EB, LBL_EB));
lblCircles[i].setName(VUOTA);
lblCircles[i].addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
for (int i = 0; i < lblCircles.length; i++) {
if (e.getSource() == lblCircles[i] && choose == 1) {
myLabelClicked(lblCircles[i], i);
}
}
}
});
add(lblCircles[i]);
}
}
protected void myLabelClicked(JLabel label, int i) {
int row = i / COLS;
int col = i % COLS;
if (!VUOTA.equals(label.getName())) {
return;
}
if (n == 0) {
n = 1;
label.setText("ok1");
tbl[row][col] = 1;
} else {
n = 0;
label.setText("ok2");
tbl[row][col] = 2;
}
label.setForeground(Color.GREEN);
label.setName("piena");
System.out.printf("tbl[%d][%d] = %d%n", row, col, tbl[row][col]);
}
private static void createAndShowGui() {
Prova2 mainPanel = new Prova2();
JFrame frame = new JFrame("Prova 2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
Within my program, I have the following code:
package io.github.AdmiralSbs.DiceWars;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Scanner;
public class HexDisplay extends JPanel {
private static final long serialVersionUID = 1L;
public static final int SIZE = 200;
private int height;
private int width;
private Hex[][] hex;
private BufferedImage myImage;
private Graphics drawer;
public HexDisplay(File f) throws IOException {
Scanner key = new Scanner(f);
int[] temp = commaSplit(key.nextLine());
height = temp[0];
width = temp[1];
hex = new Hex[width][height];
for (int w = 0; w < width; w++) {
for (int h = 0; h < height; h++) {
//temp = commaSplit(key.nextLine());
if (h % 2 == 0)
hex[w][h] = new Hex((int) (SIZE * (w + 0.5)),
(int) (SIZE * (h + 0.5)), SIZE);
else
hex[w][h] = new Hex((int) (SIZE * (w + 1.5)),
(int) (SIZE * (h + 0.5)), SIZE);
System.out.println(hex[w][h].getX() + " " + hex[w][h].getY());
}
}
key.close();
starting();
ImageIO.write(myImage, "jpg", new File("outPic.jpg"));
}
public void starting() {
setPreferredSize(new Dimension(400,400));
setLayout(new FlowLayout());
myImage = new BufferedImage(400, 400, BufferedImage.TYPE_INT_RGB);
drawer = myImage.getGraphics();
drawer.setColor(Color.BLUE);
drawer.fillRect(0, 0, 400, 400);
drawStuff(drawer);
repaint();
}
public int[] commaSplit(String s) {
String[] str = s.split(",");
int[] ret = new int[str.length];
for (int i = 0; i < str.length; i++) {
ret[i] = Integer.parseInt(str[i]);
}
return ret;
}
public void paintComponents(Graphics g) {
g.drawImage(myImage, 0, 0, this);
System.out.println("Painted");
}
public void drawStuff(Graphics g) {
for (int w = 0; w < width; w++) {
for (int h = 0; h < height; h++) {
hex[w][h].draw(g);
}
}
System.out.println("Drew");
revalidate();
repaint();
paintComponents(g);
}
}
What I would expect to happen is for the frame that contains this JPanel to display the image, but it does not. All System.out.println() methods are called as expected, and I am able to save the image as a .jpg file. However, the image is not displayed in the GUI. What can be done?
You have a typo:
// v
public void paintComponents(Graphics g) {
It should be paintComponent.
And should contain a call to super method:
super.paintComponent(g);
as the first line in the method
Hi guys i'm trying to create a draughts game in Java and am using JPanels to represent the squares, if I were to change the size of the panels how would I do so ? if I use a layout manager the squares are not big enough. At the moment i'm not using a layout manager to try and change the size, but the size doesnt seem to change - just stays at 1,1 pixel.
private void createSquares(){
for(int i = 0; i < 65; i++){
squares[i] = new JPanel();
squares[i].setLayout(null);
squares[i].setSize(20,20);
board.add(squares[i]);
}
}
You could always "borrow" an image or two online, and put that into your program. For example this code:
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.*;
import javax.imageio.ImageIO;
import javax.swing.*;
public class GetChessSquareImages {
public static final String PATH_TO_SQUARES = "http://www.colourbox.com/preview/" +
"4578561-622234-seamless-oak-square-chess-like-parquet-texture.jpg";
private static final int IMG_SIDE_COUNT = 4;
private static final double SCALE = 0.8;
private Map<SquareColor, List<Icon>> squareColorMap = new HashMap<SquareColor, List<Icon>>();
private Random random = new Random();
public void downloadImages() throws IOException {
URL lrgImgUrl = new URL(PATH_TO_SQUARES);
BufferedImage largeImg = ImageIO.read(lrgImgUrl);
int w = largeImg.getWidth() / IMG_SIDE_COUNT;
int h = largeImg.getHeight() / IMG_SIDE_COUNT;
for (int i = 0; i < IMG_SIDE_COUNT; i++) {
int x = (i * largeImg.getWidth()) / IMG_SIDE_COUNT;
for (int j = 0; j < IMG_SIDE_COUNT; j++) {
if (j != 1 && j != 2) {
int y = (j * largeImg.getHeight()) / IMG_SIDE_COUNT;
extractSubImg(largeImg, i, j, x, y, w, h);
}
}
}
}
private void extractSubImg(BufferedImage largeImg,
int i, int j, int x, int y, int w, int h) {
Image subImg = largeImg.getSubimage(x, y, w, h);
int width = (int) (w * SCALE);
int height = (int) (h * SCALE);
subImg = subImg.getScaledInstance(width, height, Image.SCALE_SMOOTH);
List<Icon> iconList = null;
if (i % 2 == j % 2) {
iconList = squareColorMap.get(SquareColor.LIGHT);
if (iconList == null) {
iconList = new ArrayList<Icon>();
squareColorMap.put(SquareColor.LIGHT, iconList);
}
} else {
iconList = squareColorMap.get(SquareColor.DARK);
if (iconList == null) {
iconList = new ArrayList<Icon>();
squareColorMap.put(SquareColor.DARK, iconList);
}
}
iconList.add(new ImageIcon(subImg));
}
public Icon getRandomIcon(SquareColor sqrColor) {
List<Icon> iconList = squareColorMap.get(sqrColor);
if (iconList == null) {
return null;
} else {
return iconList.get(random.nextInt(iconList.size()));
}
}
public static void main(String[] args) {
GetChessSquareImages getImages = new GetChessSquareImages();
try {
getImages.downloadImages();
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
int side = 8;;
JPanel panel = new JPanel(new GridLayout(side , side));
for (int i = 0; i < side; i++) {
for (int j = 0; j < side; j++) {
SquareColor sqrColor = (i % 2 == j % 2) ? SquareColor.LIGHT : SquareColor.DARK;
Icon icon = getImages.getRandomIcon(sqrColor);
panel.add(new JLabel(icon));
}
}
JOptionPane.showMessageDialog(null, panel);
}
}
enum SquareColor {
DARK, LIGHT
}
returns this JPanel:
Then your square size will be based on the sizes of your ImageIcons. For example, I have scaled my squares back with a scale factor of 0.8 (the SCALE constant above) to make the grid a more reasonable size.