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How to make jumping available only when player is on a floor in java 2d game

I am working on a donkey kong type game and like I said I want the player to only jump if he is on the floor.
I made a sort of a gravity mechanic and I check collision so he don't go through a floor and I came up with an idea that your can jump only when you are colliding. But here comes the main problem that I don't know how to tell that information to a method in another class.
Hope it makes some sense, I am a beginner and don't know if I described the problem well.
I tried to separate my code but it makes more problems
Here's a class with a player:
import java.awt.*;
import java.awt.event.KeyEvent;
public class Mario extends Rectangle {
int rychlost = 5;
int xZrychleni;
int gravitace= 5;
int yZrychleni;
int vyskok = 20;
Mario(int x, int y, int SIRKA_MARIA,int VYSKA_MARIA){
super(x, y, SIRKA_MARIA, VYSKA_MARIA);
}
public void nakresli(Graphics g) {
g.setColor(Color.white);
g.fillRect(x, y, width, height);
}
public void keyPressed(KeyEvent e) {
if(e.getKeyCode()==KeyEvent.VK_A) {
nastavSmerX(-rychlost);
}
if(e.getKeyCode()== KeyEvent.VK_D) {
nastavSmerX(rychlost);
}
if(e.getKeyCode()==KeyEvent.VK_SPACE){
nastavSmerY(vyskok);
}
}
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_A) {
nastavSmerX(0);
}
if (e.getKeyCode() == KeyEvent.VK_D) {
nastavSmerX(0);
}
if(e.getKeyCode()==KeyEvent.VK_SPACE){
nastavSmerY(0);
}
}
public void nastavSmerX ( int SmerX){
xZrychleni = SmerX;
}
public void nastavSmerY ( int SmerY){
yZrychleni = SmerY;
}
public void move () {
x = x + xZrychleni;
y = y + gravitace;
y = y - yZrychleni;
}
}
Here is a panel class where I check collisions:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class HerniPanel extends JPanel implements Runnable{
static final int HERNI_SIRKA = 1200;
static final int HERNI_VYSKA = 700;
static final Dimension SCREEN_SIZE = new Dimension(HERNI_SIRKA, HERNI_VYSKA);
static final int SIRKA_PLOSINY = 1000;
static final int VYSKA_PLOSINY = 35;
static final int SIRKA_ZEBRIKU = 25;
static final int VYSKA_ZEBRIKU = 180;
static final int MARIO_VELIKOST_XY = 50;
Thread gameThread;
Image image;
Graphics graphics;
Plosina plosina0;
Plosina plosina1;
Plosina plosina2;
Plosina plosina3;
Mario mario;
Zebrik zebrik1;
Zebrik zebrik2;
Zebrik zebrik3;
HerniPanel(){
novaPlosina();
novyMario();
novyZebrik();
this.setFocusable(true);
this.addKeyListener(new AL());
this.setPreferredSize(SCREEN_SIZE);
gameThread = new Thread(this);
gameThread.start();
}
public void novaPlosina() {
plosina0 = new Plosina(0, (HERNI_VYSKA - VYSKA_PLOSINY), HERNI_SIRKA, VYSKA_PLOSINY, 1);
plosina1 = new Plosina((HERNI_SIRKA - SIRKA_PLOSINY),(HERNI_VYSKA - VYSKA_PLOSINY - 180), SIRKA_PLOSINY, VYSKA_PLOSINY, 2 );
plosina2 = new Plosina(0, (HERNI_VYSKA - VYSKA_PLOSINY - 360), SIRKA_PLOSINY, VYSKA_PLOSINY,3 );
plosina3 = new Plosina((HERNI_SIRKA - SIRKA_PLOSINY), (HERNI_VYSKA - VYSKA_PLOSINY - 540), HERNI_SIRKA, VYSKA_PLOSINY,4);
}
public void novyMario(){
mario= new Mario(1000, (HERNI_VYSKA - VYSKA_PLOSINY - MARIO_VELIKOST_XY), MARIO_VELIKOST_XY , MARIO_VELIKOST_XY );
}
public void novyZebrik(){
zebrik1 = new Zebrik(250, (HERNI_VYSKA-VYSKA_PLOSINY-VYSKA_ZEBRIKU),SIRKA_ZEBRIKU,VYSKA_ZEBRIKU);
zebrik2 = new Zebrik(800, (HERNI_VYSKA-VYSKA_PLOSINY-VYSKA_ZEBRIKU-180),SIRKA_ZEBRIKU,VYSKA_ZEBRIKU);
zebrik3 = new Zebrik(300, (HERNI_VYSKA-360-VYSKA_PLOSINY-VYSKA_ZEBRIKU),SIRKA_ZEBRIKU,VYSKA_ZEBRIKU);
}
public void paint(Graphics g) {
image = createImage(getWidth(),getHeight());
graphics = image.getGraphics();
nakresli(graphics);
g.drawImage(image,0,0,this);
}
public void nakresli(Graphics g) {
plosina0.nakresli(g);
plosina1.nakresli(g);
plosina2.nakresli(g);
plosina3.nakresli(g);
mario.nakresli(g);
zebrik1.nakresli(g);
zebrik2.nakresli(g);
zebrik3.nakresli(g);
Toolkit.getDefaultToolkit().sync();
}
public void move() {
mario.move();
}
public void zkontrolujKolizi() {
if(mario.x<=0)
mario.x=0;
if(mario.x >= (HERNI_SIRKA-MARIO_VELIKOST_XY))
mario.x = HERNI_SIRKA-MARIO_VELIKOST_XY;
if (mario.y >= (HERNI_VYSKA-VYSKA_PLOSINY - MARIO_VELIKOST_XY)) {
mario.y = (HERNI_VYSKA - VYSKA_PLOSINY - MARIO_VELIKOST_XY);
}
if(mario.intersects(plosina1)){
mario.y = (HERNI_VYSKA-VYSKA_PLOSINY-MARIO_VELIKOST_XY-180);
}
if(mario.intersects(plosina2)){
mario.y = (HERNI_VYSKA-VYSKA_PLOSINY-MARIO_VELIKOST_XY-360);
}
if(mario.intersects(plosina3)){
mario.y = (HERNI_VYSKA-VYSKA_PLOSINY-MARIO_VELIKOST_XY-540);
}
}
public void run() {
//game loop
long lastTime = System.nanoTime();
double amountOfTicks =60.0;
double ns = 1000000000 / amountOfTicks;
double delta = 0;
while(true) {
long now = System.nanoTime();
delta += (now -lastTime)/ns;
lastTime = now;
if(delta >=1) {
move();
zkontrolujKolizi();
repaint();
delta--;
}
}
}
public class AL extends KeyAdapter{
public void keyPressed(KeyEvent e) {
mario.keyPressed(e);
}
public void keyReleased(KeyEvent e) {
mario.keyReleased(e);
}
}
}

Drawing new Graphics in ArrayList

I have an application, in which a car is moving on a panel and it creates sound waves - circles. I want to :
1) have a few circles at the moment of opening the frame
2) when the Start button is selected I want them to move and I want more circles to be created, one after another, until the stop button is selected
the problem is:
1) when the frame is opened there are 5 circles, but they totally do not move
2) 5 new circles appears, but from the same XY position, they are just bigger - I want one circle after another, it grows, and next one appears
here is my code, I would appreciate some helpful sample or could you tell me where my mistake is. I used amount of 5 just to have some samples of waves.
public class WaveParameters {
int xPos=0;
int yPos = 375;
int width=60;
int height=60;
int velX = 0 ;
private Color color = Color.WHITE;
public int getVelX() {
return velX;
}
public void setVelX(int velX) {
this.velX = velX;
}
public int getX() {
return xPos;
}
public void setX(int xPos) {
this.xPos = xPos;
}
public int getWidth(){
return width;}
public int getHeight(){
return height;}
public void setWidth(int width) {
this.width = width;
}
public void setHeight(int height) {
this.height = height;
}
public Color getColor() {
return color;
}
public void setColor(Color color) {
this.color = color;
}
public void paint(Graphics g){
g.setColor(getColor());
g.drawOval(xPos,yPos,width/2,height/2);
}
}
Here is the panel of animation:
public class PanelAnimation extends JPanel implements ActionListener{
List<WaveParameters> waves = new ArrayList<WaveParameters>();
public PanelAnimation(ResourceBundle bundle) {
super();
resourceBundle = bundle;
t.start();
try {
imageBackground = ImageIO.read(newFile("bg.png"));
} catch (IOException ex) {
// handle exception...
}
}
CarParametrs pAuto = new CarParametrs();
HumanParametrs pHuman = new HumanParametrs() ;
Timer t = new Timer(60,this);
//WaveParameters pWave = new WaveParameters();
private BufferedImage imageBackground;
MainFrame mf;
public void addAuto(){
CarParametrs ap = new CarParametrs();
ap.setX(0);
pAuto = ap;
}
public void addHuman(){
HumanParametrs acz = new HumanParametrs();
acz.setX(0);
pHuman = acz;
}
public void addWave() {
for (int i=0; i<5; i++) {
WaveParameters wave = new WaveParameters();
// wave.setX(pAuto.xPos);
wave.setColor(Color.white);
wave.setWidth(wave.width*i);
wave.setHeight(wave.height*i);
waves.add(wave);
}
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(imageBackground, 0, 0, null);
pAuto.paint(g);
pHuman.paint(g);
//if(mf.buttonStart.isSelected()) {
addWave();
//for (int i=0; i<5; i++) {
for (WaveParameters w : waves) {
// waves.add(new WaveParameters());
w.setX(pAuto.xPos);
w.paint(g);
//}
}
//}
}
public void actionPerformed(ActionEvent e) {
CarParametrs pa = pAuto;
pa.xPos += pa.velX;
/*//WaveParameters wp = pWave;
wp.xPos = pa.xPos;
wp.xPos+=wp.velX;
wp.height+=wp.velX;
wp.width+=wp.velX;
wp.yPos-=wp.velX/5 ;*/
for (WaveParameters w : waves) {
w.xPos = pa.xPos;
w.xPos+=w.velX;
w.height+=w.velX;
w.width+=w.velX;
w.yPos-=w.velX/5 ;
}
repaint();
}
and here is a wave-part of action listener for Start Button:
List<WaveParameters> wave = panelAnimation.waves;
for (WaveParameters w : wave) {
for (int i=0;i<5;i++) {
wave.add(new WaveParameters());
w.velX = Integer.parseInt(button2.getName());
w.xPos += w.velX;
w.width++;
w.height++;
w.yPos-=w.velX/5;
}
}
panelAnimation.repaint();

The five new bigger circles that appear are likely due to the last chunk of code where you iterate through all the waves in panel animation.
The "wave.add(new WaveParameters());" seems unnecessary, and may be the reason why your old waves are staying. Delete that line, and it may work.

Java NullPointerException (need some timer)

I draw simple splines and I got code here. I editted code and receive NullPointerException in dataset.size(). I guess that my programm don't be at time filling all dataset points from files (Scanner works slowly) and it throws this error. I also guess that I need to add certain timer to wait while dataset == null. But how to make it?
public class SimpleGrapher2 extends JPanel {
...
private static List<Double> scores;
private static File[] sFiles;
...
private static List<List<Point2D.Double>> dataset;
private static int snumber = 0;
public SimpleGrapher2(List<Double> scores) {
SimpleGrapher2.scores = scores;
addMouseMotionListener(new MouseMotionListener() {
#Override
public void mouseDragged(MouseEvent me) {
double x = me.getX();
double y = me.getY();
List<Point2D.Double> series = findNearPoint(dataset, x, y);
editSerie(x, y, series);
revalidate();
repaint();
}
#Override
public void mouseMoved(MouseEvent me) {}
});
}
static JPanel paintingComponent = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
//painting X,Y axises
drawSplines(g2); // painting splines
}
};
public static void drawSplines(Graphics2D g2) {
int precision = 10;
for (int k = 0; k < dataset.size(); k++) { // NULLPOINTEREXCEPTION HERE
List<Point2D.Double> series = dataset.get(k);
int np = series.size();
//algorithm and painting of splines
}
}
public List<Point2D.Double> findNearPoint(List<List<Point2D.Double>> dataset, double x, double y) {
//hidden part of code: to move points
}
public void editSerie(double x, double y, List<Point2D.Double> serie) {
//hidden part of code: edit series in case of MouseDragged
}
public void readFromFiles() {
dataset = new ArrayList<>();
for (File polFile : sFiles) {
List<Point2D.Double> series = new ArrayList<>();
Scanner s = null;
try {
s = new Scanner(new File(polFile.getAbsolutePath()));
}catch (FileNotFoundException ex) {
System.out.println("Scanner error!");
}
s.useLocale(Locale.US);
while (s.hasNext()) {
double x = s.nextDouble();
double y = s.nextDouble();
series.add(new Point2D.Double(x, y));
}
dataset.add(series);
}
}
//hidden part of code: some helpfull functions
private static void createAndShowGui() {
...
SimpleGrapher2 mainPanel = new SimpleGrapher2(scores);
mainPanel.setPreferredSize(new Dimension(800, 600));
JFrame frame = new JFrame("DrawGraph");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
//frame.setContentPane(new GLG2DCanvas(paintingComponent));
frame.setContentPane(paintingComponent);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGui();
}
});
}
}

Why does this not draw my Polygon? (Java game)

Basically, all that shows up is a JFrame with the black JPanel inside but no Ball/polygon anywhere. It's really annoying me now and I can't see the reason why. Any help greatly appreciated.
EDIT: Added code. Sorry for posting to Github, didn't know it was frowned upon.
public class Board extends JFrame {
private int width = 800;
private int height = 1000;
private int currentKeyCode = 0;
private boolean keyHeldDown = false;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
Board b = new Board();
b.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Board() {
setSize(width, height);
setTitle("Drop");
setBackground(Color.BLACK);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
currentKeyCode = KeyEvent.VK_RIGHT;
keyHeldDown = true;
System.out.println("Right + 10");
}
if (e.getKeyCode() == KeyEvent.VK_LEFT) {
currentKeyCode = KeyEvent.VK_LEFT;
keyHeldDown = true;
System.out.println("Left + 10");
}
if (e.getKeyCode() == KeyEvent.VK_P) {
currentKeyCode = KeyEvent.VK_P;
keyHeldDown = true;
System.out.println("Pause");
}
}
#Override
public void keyReleased(KeyEvent e) {
keyHeldDown = false;
}
});
setContentPane(new Panel(this));
ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(5);
executor.scheduleAtFixedRate(new RepaintBoard(this), 0L, 20L, TimeUnit.MILLISECONDS);
}
#Override
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
#Override
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
private class RepaintBoard implements Runnable {
final Board board;
public RepaintBoard(Board board) {
this.board = board;
}
#Override
public void run() {
board.repaint();
}
}
}
class Panel extends JComponent {
Ball ball;
private Board board;
public Panel(Board board) {
this.board = board;
ball = new Ball();
}
#Override
public void paint(Graphics g1) {
Graphics2D g = (Graphics2D) g1;
g.setColor(Color.BLACK);
g.drawRect(0, 0, board.getWidth(), board.getHeight());
g.drawPolygon(ball);
}
}
class Ball extends Polygon {
private int radius = 5;
private Point loc;
private int[] xPos = new int[radius * 2 + 1];
private int[] yPos = new int[radius * 2 + 1];
public Ball() {
for (int i = -radius, j = 0; i <= radius; i++, j++) {
xPos[j] = i;
yPos[j] = i;
}
new Ball(xPos, yPos, radius * 2 + 1, 100, 100);
}
public Ball(int[] xPos, int[] yPos, int points, int x, int y) {
super(xPos, yPos, points);
loc = new Point(x, y);
for (int i : xPos) {
System.out.println(i);
}
}
}

Don't have Ball extends Polygon
Put a drawBall(Grapchics g) {} method in the Ball class, and do your ball painting in there.
call the drawBall method in the paint
ball.drawBall(g);
Don't override paint, instead override paintComponent on the panel, and don't forget to call super.paintComponent
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
}
This new Ball(xPos, yPos, radius * 2 + 1, 100, 100); in your constructor does absolutely nothing. You should instead just use the second constructor, and create the ball with that constructor. Each ball should be different, so a no-arg constructor is pointless

Graphics will not cover entire canvas

What I know: Canvas is displayed properly, due to the yellow. However, graphics will not cover the canvas completely, nor will my law class recognized it past the end of the black area...
So what is causing this to happen? And how could I draw on my currently undrawable section of canvas(yellow part), or should I just implement my graphics another way?
EDIT: The UI class creates a canvas and a buffer, then the graphics class takes over and starts drawing on them, however for some reason it cannot in the yellow section, nor will the Law Class which handles collision with the red cube and walls of the app, regogize the yellow area as a valid place to go. Even through the same variables for dimensions, were used everywhere.
Main Class
package app;
public class Main {
static final int X = 1024;
static final int Y = 680;
static final int sanic = 10;
int fps = 0;
int frames = 0;
long totalTime = 0;
long curTime = System.currentTimeMillis();
long lastTime = curTime;
static int[] pos;
Graphics graphics;
Law physics;
static int status;
boolean holdState;
public Main() {
pos = new int[5];
pos[1] = X;
pos[2] = Y;
}
public void launch() {
// Audio sound = new Audio();
graphics = new Graphics();
physics = new Law();
graphics.draw();
// sound.play();
handle();
}
public void update() {
graphics.cache();
physics.check();
graphics.render();
try {
Thread.sleep(10);
} catch (Exception e) {
} finally {
graphics.dump();
}
}
public void handle() {
while (!isOver()) {
if (!isPaused()) {
update();
}
}
}
boolean isOver() {
if (status == 1) {
status = 0;
return true;
}
return false;
}
boolean isPaused() {
if (status == 2) {
status = 0;
if (!holdState) {
holdState = true;
pos[3] = pos[1];
pos[4] = pos[2];
} else if (holdState) {
holdState = false;
pos[1] = pos[3];
pos[2] = pos[4];
}
}
return holdState;
}
public static void main(String[] args) {
Main game = new Main();
game.launch();
}
}
UI Class
package app;
import java.awt.*;
import java.awt.image.*;
import java.net.URL;
import javax.swing.*;
public class UI extends Main {
JFrame mainWin;
Canvas wall;
URL pic;
Toolkit kit;
Image img;
BufferStrategy Buffer;
Graphics2D shell;
Graphics2D ball;
public UI() {
mainWin = new JFrame("Game");
wall = new Canvas();
wall.addKeyListener(new Input());
}
void draw() {
frame();
icon();
canvas();
show();
prep();
}
void frame() {
mainWin.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainWin.setBackground(Color.BLUE);
mainWin.setIgnoreRepaint(true);
}
void icon() {
pic = ClassLoader.getSystemResource("res/app.png");
kit = Toolkit.getDefaultToolkit();
img = kit.createImage(pic);
mainWin.setIconImage(img);
}
void canvas() {
wall.setBackground(Color.YELLOW);
wall.setIgnoreRepaint(true);
wall.setBounds(0, 0, X, Y);
}
void show() {
mainWin.add(wall);
mainWin.pack();
mainWin.setResizable(false);
mainWin.setLocationRelativeTo(null);
mainWin.setVisible(true);
}
void prep() {
wall.createBufferStrategy(2);
Buffer = wall.getBufferStrategy();
}
}
Graphics Class
package app;
import java.awt.*;
public class Graphics extends UI {
public void render() {
mask();
player();
fps();
Buffer.show();
}
void cache() {
shell = (Graphics2D) Buffer.getDrawGraphics();
ball = (Graphics2D) Buffer.getDrawGraphics();
}
void dump() {
shell.dispose();
ball.dispose();
}
void mask() {
shell.setColor(Color.black);
shell.fillRect(0, 0, X, Y);
}
void fps() {
lastTime = curTime;
curTime = System.currentTimeMillis();
totalTime += curTime - lastTime;
if (totalTime > 1000) {
totalTime -= 1000;
fps = frames;
frames = 0;
}
frames++;
shell.setColor(Color.GREEN);
shell.setFont(new Font("Courier New", Font.PLAIN, 12));
shell.drawString(String.format("FPS: %s", fps), 20, 20);
}
void player() {
ball.setColor(Color.RED);
ball.fillRect(pos[1], pos[2], 32, 32);
}
}
Law Class
package app;
public class Law extends Main {
public void check() {
out();
}
void out() {
if (pos[1] < 0) {
pos[1] = 0;
}
if (pos[2] < 0) {
pos[2] = 0;
}
if (pos[1] > X - 32) {
pos[1] = X - 32;
}
if (pos[2] > Y - 32) {
pos[2] = Y - 32;
}
}
}

This is a bug with Frame#setResizable. Don't ask me why, but it wants to add about 10 pixels to the width and height of the frame.
The best solution I know is to call setResizable BEFORE pack
void show() {
mainWin.add(wall);
mainWin.setResizable(false); // Call me first
mainWin.pack();
mainWin.setLocationRelativeTo(null);
mainWin.setVisible(true);
}

You're not interacting with Swing properly, and you're doing unsafe things with a default Graphics object you should not be touching. Here's the bare bones of what needs to happen, in order.
JFrame mainFrame = new JFrame()
MyCanvas myCanvas = new MyCanvas()
mainFrame.getContentPane().add(myCanvas, BorderLayout.CENTER)
mainFrame.setVisible(true);
new Thread(myThread).start()
Main.main() returns.
MyCanvas needs to look something like this:
public class MyCanvas extends Canvas {
public void paint(Graphics g) {
// drawing code goes here
} // g is now no longer valid. Don't hold onto it or dispose it or anything.
}
Here's the physics update thread:
public class MyThread implements Runnable {
public void run() {
while (keepRunning()) {
physics.update();
myCanvas.repaint(); // myCanvas.paint() will eventually be called
sleep(10);
}
System.exit(0);
}
}
You probably want to add constructors to these objects and pass in references to your other objects they need to reference.