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How to fix Java listening to more than 1 key at a time?

Me and my partner are attempting to create the game Pong for our computer science final project. We created a reference code where 2 cubes can be controlled upwards and downwards and it works fine. The problem occurs when attempting to control both cubes at the same time (only 1 cube will move at a time). We want to make both cubes move at the same time.
WE want to say that:
yPos - is the y position of the black cube
xPos - is the x position of the black cube
xPos2 - is the x position of the blue cube
YPos2 - is the y position of the blue cube
Keys:
A - Go up for black cube
Z - Go down for black cube
K - Go up for blue cube
M - go down for blue cube
We have tried using a more complicated version which used j-label animation. How ever we want to make our pong game through the graphics function. But we do not understand:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class PongHelpNeed extends JFrame implements KeyListener
{
// booleans to tell which key is pressed
boolean upKey;
boolean downKey;
boolean upKey2;
boolean downKey2;
// the position variables
int yPos;
int xPos;
int xPos2;
int yPos2;
public PongHelpNeed ()
{
//create window
super ("Controller");
setSize (660, 700);
// set keys to false and original positions
upKey = false;
downKey = false;
upKey2 = false;
downKey2 = false;
xPos = 100;
yPos = 350;
xPos2 = 500;
yPos2 = 350;
// add the frame as a listener to your keys
addKeyListener (this);
// Show the frame
setVisible(true);
}
//needs to be here because the class implements KeyListener
public void keyTyped (KeyEvent e)
{
System.out.println (e.getKeyCode () + " Typed");
}
//needs to be here because the class implements KeyListener
public void keyPressed (KeyEvent e) {
//check if keys a,z or k,m are pressed
if (e.getKeyCode () == KeyEvent.VK_A)
{
upKey = true;
}
else if (e.getKeyCode () == KeyEvent.VK_Z)
{
downKey = true;
}
else if (e.getKeyCode () == KeyEvent.VK_K)
{
upKey2 = true;
}
else if (e.getKeyCode () == KeyEvent.VK_M)
{
downKey2 = true;
}
//repaint the window everytime you press a key
repaint ();
}
//needs to be here because the class implements KeyListener
public void keyReleased (KeyEvent e)
{
System.out.println (e.getKeyCode () + " Released");
}
//paints the pictures
public void paint (Graphics g)
{
//set background
g.setColor(Color.WHITE);
g.fillRect(0, 0, 660, 700);
//cube 1
g.setColor(Color.BLACK);
g.fillRect(xPos,yPos,50, 50);
//draw cube 2
g.setColor(Color.BLUE);
g.fillRect(xPos2,yPos2, 50, 50);
//if keys are pressed move the cubes accordingly up or down
if (upKey == true)
{
yPos = yPos - 15;
upKey = false;
}
else if (downKey == true)
{
yPos = yPos + 15;
downKey = false;
}
else if (downKey2 == true){
yPos2 = yPos2 + 15;
downKey2 = false;
}
else if (upKey2 == true) {
yPos2 = yPos2 - 15;
upKey2 = false;
}
}
public static void main (String[] args)
{
new PongHelpNeed ();
}
}
Our expected results are we are trying to move both cube at the same time. So when we press the A key and the K key the black square should move and the blue cube should move.

Calling repaint() does not trigger a call to the paint immediately, so it's possible that the keyPressed is triggered twice (or more) before paint.
In your paint method you are checking the keys in if-else, which means that if one of the flags is true, the rest are not checked. You also have a race condition where the keyPressed is fighting with paint over the flags. Also, if you press a key quickly multiple times, you'll lose all the extra key presses between the first handled event and the next repaint.
Instead of doing the move within paint, you should do it within the keyPressed handler. Don't set a flag to e.g. upKey = true;, but instead do the action directly: yPos = yPos - 15;. The paint method will then just refresh the view to reflect the current (updated) state.

Add a node in a gridpane using mouse

I'm trying to do a quite easy boardgame (Carcassonne) but I'm having a lot of troubles with the graphic interface. The problem is that I don't see the way to make a relation between the mouse clicks and the gridpane row and columns.
The first tile is given and it's always added to the 100, 100 gridpanes position. You won't see it in the code, but for each tile added if the adjacents are empty it's added a white tile, so it looks like this:
Then, the player is expected to do a legal move ( we're not controlling cheaters, so yeah, it will be a weak game ) in the positions x = 99 y = 100, x = 101 y = 100, x = 100 y = 99, x = 100 y = 101.
But when i click there using the method play() the e.getSceneX(); method returns me the pixel position, and I need a way to convert it to a valid row index. So this is happening:
This is the console output:
tile XCCCC added at 100 100 // this is always given by the program, it's always the same
tile MFFCF added at 391 380
In this case, I clicked to the x = 100 y = 101 gridpane but the mouse returned me the pixel 391, 380.
Any idea?
This is the structure of my code:
public final class GUI extends Application {
private Game _game;
private GridPane _visualBoard;
#Override
public void start(final Stage primaryStage) {
// some stuff setting the gridpane, which will be inside a scrollpane and the scrollpane will be inside a borderpane which will alse have 2 additional VBoxes with the current turn information
play();
primaryStage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
public void play() {
_visualBoard.setOnMousePressed((MouseEvent e) -> {
double x = e.getSceneX();
double y = e.getSceneY();
_game.doMove(x, y);
});
}
public void insertTile(myTile r, int x, int y) {
myVisualTile rV = new myVisualTile(r);
_visualBoard.add(rV, x, y);
}
And this is the class game:
public class Game {
private GUI _gui;
private List<Player> _players; // An arraylist of players
private int _currentPlayer; // The index of the current player in the ArrayList
private Board _board; // The logical board, totally separeted from the gridpane
private tileStack _stack;
public void doMove(double x, double y) {
int ax = (int) x;
int ay = (int) y;
if (_stack.isEmpty()) {
System.out.println("Game finnished");
//stuff
}
else {
myTile r = _stack.poll(); // takes the first tile of the stack
_gui.insertTile(r, ax, ay);
}
}

public void play() {
_visualBoard.setOnMousePressed((MouseEvent e) -> {
Node source = (Node)e.getTarget() ;
Integer x = GridPane.getColumnIndex(source);
Integer y = GridPane.getRowIndex(source);
_game.doMove(x, y);
});
}
That actualy worked. Thanks everybody!

Mouse Drag To Zoom implementation Java - not on click

I have written some code to implement a drag to zoom (i.e. draw a rectangle with the mouse and then zoom into this area so it fills the container) on a JPanel. However, before I wrote this into the Listener, I had a "mouseClicked" method, which is still there. This method performed a different function, simply returning the coords of the click.
Unfortunately, I mistakenly implemented the zoom function using MousePressed, which thus runs at the same time as the mouseClicked event. This means that when I click the mouse to get the coordinates, it also zooms in on a very small rectangle. Is there anyway to change this?
Thanks in advance for any suggestions, and please let me know if you need anything clarifying!
Here is the listener class:
class panelClickListener extends MouseAdapter implements MouseMotionListener {
JLabel toShowCoords, rangeLabel;
juliaPanel panelJulia;
mandPanel panelMand;
int startX, startY, currentX, currentY;
boolean dragging;
ComplexNumber startRange, endRange;
public panelClickListener(JLabel toShowCoordsIn, juliaPanel panelJuliaIn, mandPanel panelMandIn, JLabel rangeLabelIn) {
toShowCoords = toShowCoordsIn;
panelJulia = panelJuliaIn;
panelMand = panelMandIn;
rangeLabel = rangeLabelIn;
}
public void mouseClicked(MouseEvent e) {
int x = e.getX();
int y = e.getY();
userSelectedPoint = pointsToDrawOn[x][y];
toShowCoords.setText("Number Selected: " + userSelectedPoint.getReal() + " , " + userSelectedPoint.getImaginary());
panelJulia.setFixedNumber(pointsToDrawOn[x][y]);
panelJulia.repaint();
}
public void mousePressed(MouseEvent event) {
Point point = event.getPoint();
startX = point.x;
startY = point.y;
dragging = true;
}
public void mouseReleased(MouseEvent event) {
dragging = false;
startRange = pointsToDrawOn[startX][startY];
endRange = pointsToDrawOn[currentX][currentY];
maxVal = endRange;
minVal = startRange;
rangeLabel.setText("Real axis: " + minVal.getReal() + "," + maxVal.getReal() + " - Imaginary axis: " + minVal.getImaginary() + "," + maxVal.getImaginary());
populatePointArray();
panelMand.repaint();
}
public void mouseDragged(MouseEvent event) {
Point p = event.getPoint();
currentX = p.x;
currentY = p.y;
}
}

dragging should only be set to true when mouseDragged is called, then when mouseReleased is called, you need to check to see if dragging is true before processing the zoom
There's some theory to go with that, mouseClicked will only be called if the point of the mouse is the same for mousePressed and mouseReleased.
So in a click operation you can expect mousePressed, mouseReleased and mouseClicked to be called (I believe in that order, but you'd better test it).
In a drag operation, you can expect mousePressed, mouseDragged and mouseReleased to be called

LibGDX: Problems with getting Bounds

I have a Problem with getting x and y of a Table.
I have a menu that contains Cells of MenuItems. Now I whant to check if an touchDown outside of the table has happen with a sipmle AABB dedection.
This works fine!
Now I whant to add subMenus outside of the Table and do table.addActor(subMenu).
Now it doesnt works.
If i print x and y i get 1.0, 1.0 but this are not correct values.
With table.getX(align) I get also bad values.
public void addItem (MenuItem item) {
add(item).fillX().row();
pack();
item.addListener(menuItemListener);
PopupMenu subMenu = item.getSubMenu();
if (subMenu != null) {
subMenu.setParent(this);
subMenu.setStage(getStage());
}
}
public void showMenu() {
getParent().addActor(this);
Stage stage = getStage();
if (stage != null) stage.addListener(stageListener);
}
/** Hides this popupMenu and all its subMenus */
protected boolean hideMenu() {
if (!getParent().getChildren().removeValue(this, true)) return false;
Stage stage = getStage();
if (stage != null) {
stage.removeListener(stageListener);
stage.unfocus(this);
}
childrenChanged();
return true;
}
public boolean contains (float x, float y) {
return getX() <= x && getX() + getWidth() >= x && getY() <= y && getY() + getHeight() >= y;
}
public boolean menuStructureContains (float x, float y) {
return contains(x, y) || subMenu != null && subMenu.menuStructureContains(x, y);
}
I but I need the x and y of the Cells (getting the values of them doesnt work too).
EDIT: The position of the Menu gets changed by a other class. If I convert x, y of the Menu to stage and do not set its position it works.
If i set the potition it doubles the converted x / y value.

From here, simply create a class which gives you the location of the actor on the stage.
public static Vector2 getStageLocation(Actor actor) {
return actor.localToStageCoordinates(new Vector2(0, 0));
}
The reason you need to use a new vector at (0,0) is because that is the bottom left corner of you actor. It will then convert this to the stage coordinates and give you the actual location of the actor.
Then you can do getStageLocation.x; and getStageLocation.y;
Hope this helps

Dragging A Circle on a JFrame

I am trying to have a circle appear on the screen, then when the user clicks INSIDE the circle, enable the ability for them to drag the circle where the mouse goes while it is being pressed.
This is the code i have so far, the drag works, but it is allowing the user to drag without them pressing the inside of the circle, just when anywhere on the screen is pressed.
I hope i am not too confusing
here's the code i have, please if someone could just tell me the code that needs to be corrected, it will save me anymore hours.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class DragCircle extends JFrame {
private static final long serialVersionUID = 1L;
public static int size = 400;
public static int r = 10;
private int x;
private int y;
private int cX;
private int cY;
private int dX;
private int dY;
private MouseHandler mh;
boolean isCircleClicked = false;
public static void main(String[] args) {
DragCircle c1 = new DragCircle();
c1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public DragCircle() {
super("Drag circle");
cX = r + 100;
cY = r + 100;
mh = new MouseHandler();
addMouseListener(mh);
addMouseMotionListener(mh);
setSize(size, size);
setVisible(true);
}
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.RED);
g.fillOval(cX, cY, r * 2, r * 2);
}
private class MouseHandler extends MouseAdapter implements
MouseMotionListener {
public void mousePressed(MouseEvent me)
{
if ((cX - me.getX()) * (cX - me.getX()) + (cY - me.getY())
* (cY - me.getY()) < r * r) {
isCircleClicked = true;
}
}
public void mouseDragged(MouseEvent me) {
if (isCircleClicked) {
x = me.getX() - dX;
y = me.getY() - dY;
cX = x + r;
cY = y + r;
repaint();
}
}
public void mouseReleased(MouseEvent e) {
isCircleClicked = false;
}
}
}

Your one problem is with
public void mouseDragged(MouseEvent me) {
if (isCircleClicked = true) {
What you're doing here is setting isCircleClicked to true every time you drag the mouse. Also this statement evaluates to true which is why you can drag anywhere and move the circle. Change this to
if (isCircleClicked) {
and you should be fine here.
The next problem is that you never reset isCircleClicked to false. You should be doing this either in mouseReleased or change your mousePressed as follows:
public void mousePressed(MouseEvent me) {
isCircleClicked =
(cX - me.getX()) * (cX - me.getX()) +
(cY - me.getY)) * (cY - me.getY()) < r * r;
}
which will set isCircleClicked accordingly.
There is still something to do, though. In the current form you need to start dragging to the upper-left of the center point, as illustrated below:
+------+
| |
| .-|-.
| / | \
+------+ |
\ /
'-_-'
This is because of your drawing: fillOval takes an upper-left corner of the oval and a width and height of the bounding rectangle. It's not the center point and the respective diameters. Hence you need to adapt his as follows:
g.fillOval(cX - r, cY - r, r * 2, r * 2);
Note the offset by the radius to the left and top.
Furthermore, your dragging code needs a bit more work. You are currently assuming that the user drags the circle's center. What you need to do is save the coordinates of the mouse click and then move the circle based on the mouse's movement relative to the last point. Currently you're moving relative to the circle's center so for the movement to be nice you have to start dragging exactly in the center of the circle. I'll leave that as an exercise for you :-)
Besides, your listener class already inherits from MouseAdapter so you don't need to explicitly implement the MouseMotionListener since MouseAdapter implements it already.

The structure of you program is wrong. You should never override the paint(...) method of a JFrame. That is an old AWT trick and should NOT be used with Swing.
Read the section from the Swing tutorial on Custom Painting for an example of the proper way to do painting. The basics are to override the paintComponent(...) method of a JPanel and then add the panel to the content pane of the frame.
With regards to you question a better solution is to create an Elllipse2D object to represent your circle. Then the custom painting can use the drawShape(...) method of the Graphics2D class. Then in you MouseListener code you can use the Shape.contains(...) method to see if the mouse was clicked on the circle.