So, what I have is a program that plots Phase trajectories. At the moment the starting points are all random, but what I am trying to add is a way for the program to start a trajectory from the point I click on. I've been fiddling with it for hours, trying everything I know, well here's the code:
public static void click(final double r, final double t) {
MouseListener mus = new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
double r = e.getX();
double t = e.getY();
}
};
}
public Vector<Graph> getGraphs() {
// ... bunch of code that draws the graph...
g.add(new Graph.Line());
g.lastElement().add(r, t);
g.lastElement().setColor(Color.blue);
And what it tells me is that r and t can't be found. I realize that it might be hard to help without the whole code, but it is loads of code, I can email it to someone if you are really willing to help. But in any other case, anyone got an idea what I can do?
1) r and t are not in scope for your getGraphs() method.
2) You don't seem to have registered your mouse adapter as a MouseListener anywhere
3) It is not clear how the click() method gets called
You need to capture the mouse clicks from a window component, let's say it is a JPanel that you are using.
Then your code would look something like this:
public class MyApplication {
private JFrame myWindow = new JFrame("My Application");
private JPanel myPanelYouCanClick = new JPanel();
public MyApplication() {
myWindow.setContantPane(myPanelYouCanClick);
myPanelYouCanClick.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
double r = e.getX();
double t = e.getY();
// Code to create your new trajectory called from here, pass
// in the values of r and t if required. Remember you are
// running on the event dispatcher thread!
}
});
myWindow.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
MyApplication app = new MyApplication();
}
});
}
}
Related
I am trying to simplify the Javax swing graphics classes in order to make it easier for other people to get into Java graphics, but I am facing a problem with testing it.
Keep in mind, that I am writing the main method as a user of the code and not the developer. I need answers that will change the code of the class methods and not the main method.
What my main method code is supposed to do is print 'hovering' when the user hovers over the button. However, when I add a SOP statement before the if statement, it works...
The method for the mouse hovering is in the Button class.
Here is my main method code -
public static void main(String[] args) {
GraphWin win = new GraphWin(1000, 1000, "Graphics Window - Test");
win.show();
Button button = new Button(new Point(380, 300), new Point(620, 400));
button.draw(win);
enter code herewhile(true) {
//System.out.println(button.hovering);
if(button.hovering) {
System.out.println("hovering");
}
}
}
And here is my code for the Button class -
public class Button implements MouseListener{
public JButton button;
public boolean clicked = false, hovering = false, pressed = false;
public Button(Point p, Point p2) { //This is the default constructor of the button with only 2 points specified
this.button = new JButton();
this.setBounds(p, p2);
this.button.addMouseListener(this);
this.setBorderVisible(false);}
public Button(Point p, Point p2, String text) { //This constructor requires text to be displayed`enter code here`
this.button = new JButton(text);
this.setBounds(p, p2);
this.button.addMouseListener(this);
this.setBorderVisible(false);}
public Button(String icon, Point p, Point p2) { //This constructor sets an Icon for the button
this.button = new JButton();
this.setIcon(icon);
this.setBounds(p, p2);
this.button.addMouseListener(this);
this.setBorderVisible(false);}
public Button(Point p, Point p2, String text, String icon) { //Here, both the text and Icon is specified
this.button = new JButton(text);
this.setIcon(icon);
this.setBounds(p, p2);
this.button.addMouseListener(this);
this.setBorderVisible(false);}
public void draw(GraphWin win) {
win.window.add(this.button);}
public void setBounds(Point p, Point p2) {
this.button.setBounds(p.x, p.y, p2.x - p.x, p2.y - p.y);
}
public void setEnabled(boolean enable) {
this.button.setEnabled(enable);}
public void disable() {
this.button.setEnabled(false);}
public void enable() {
this.button.setEnabled(true);
}
public void setColor(Color color) {
this.button.setBackground(color);}
public void setColor(String color) {
this.button.setBackground(Color.decode(color));}
public void setText(String text) {
this.button.setText(text);}
public void setIcon(String icon) {
File imageCheck = new File(icon);
if(!imageCheck.exists())
System.out.println("Image file not found!");
else
this.button.setIcon(new ImageIcon(icon));
}
public void resizeIcon(String icon, int width, int height) {
Image img = new ImageIcon(icon).getImage();
img = img.getScaledInstance(width, height, Image.SCALE_SMOOTH);
this.button.setIcon(new ImageIcon(img));
}
public void setCustomMargins(int top, int bottom, int left, int right) {
this.button.setMargin(new Insets(top, left, bottom, right));}
public void setMargins(int m) {
this.button.setMargin(new Insets(m, m, m, m));}
public void setLabel(String label) {
this.button.setToolTipText(label);
}
public void setBorderVisible(boolean border) {
this.button.setBorderPainted(border);}
public void setOpaque(boolean opaque) {
this.button.setContentAreaFilled(opaque);}
#Override
public void mouseEntered(MouseEvent arg0) {
this.hovering = true;
System.out.println(1);
}
#Override
public void mouseExited(MouseEvent arg0) {
this.hovering = false;
}
#Override
public void mousePressed(MouseEvent arg0) {
this.pressed = true;
}
#Override
public void mouseReleased(MouseEvent arg0) {
this.pressed = false;
}
#Override
public void mouseClicked(MouseEvent e) {
this.clicked = true;
System.out.println(1);
}
}
This sort of thing is usually to do with threading.
Events in Swing are dispatched on the AWT Event Dispatch Thread (EDT). In order to be thread-safe, practically everything dealing with Swing/AWT should be done on the EDT.
In your case, there is no kind of locking between the variable being set and read. Adding a println causes a pause (with all sorts of memory barriers or whatnot) that happens to allow the program to run in the desired sequence.
You've probably seen main methods written to pass execution straight over to the AWT.
class MyGUI {
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(MyGUI::go);
}
private static void go() {
...
It might be better to supply the main class yourself, implemented such that it takes the application class as an argument and passes execution on once everything is setup. Whilst traditionally command lines use a main static method/function, everywhere else subtypes: Applets, Servlets, etc.
best approach would be to use a isHovering() method but educated guess on the behavior inside a while(true) with or without a Sysout might be related to a compiler optimisation. Might be fixed by putting the hovering variable as transient
I have been trying to create a 'catch me if you can' game: when I start it, it randomly chooses where to allocate a 'click me' button. I am not supposed to be able to click the button, the text should be re-assigned to another button before I am able to do that.
It works for a while but then it throws the following error: "java.awt.AWTEventMulticaster.mouseMoved".
I have been trying to fix the problem with removeListener() method but I don't seem to be able to find a solution. Any comments?
Here's my code:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.lang.*;
public class Game extends JFrame {
//Panels
private JPanel mainPanel = new JPanel();
// Buttons
private JButton[] buttons = new JButton[9];
private JButton theChosenButton = new JButton();
// other
private int random = 0;
public Game() {
this.setTitle("Catch me if you can");
mainPanel.setLayout(new GridLayout(3, 3));
// creates buttons
for(int i = 0; i < 9 ; i++) {
buttons[i] = new JButton();
mainPanel.add(buttons[i]);
}
// Add everything to frame
this.getContentPane().add(mainPanel);
this.setSize(400, 400);
this.setVisible(true);
}
// generates random number between 1 and 9 to be used
public int clickMeGenerator(){
random = (int) Math.floor(Math.random() * 9);
return random;
}
// randomly assigns clickMeGenerator to a button
// add mouseMoved listener to the chosen button
public void assign(){
int randomButton = this.clickMeGenerator();
theChosenButton = buttons[randomButton];
theChosenButton.addMouseMotionListener(new MouseHover());
theChosenButton.setText("Click me");
}
public void removeListener() {
theChosenButton.removeMouseMotionListener(new MouseHover());
//}
}
// inner class
class MouseHover implements MouseMotionListener {
public void mouseMoved(MouseEvent e) {
theChosenButton.setText("");
Game.this.assign();
}
public void mouseDragged(MouseEvent e) {
}
}
} // end of class
Test class:
public class GameTest {
public static void main (String args[]) {
Game myGame = new Game();
myGame.assign();
}
}
Thank you so much for your help!
Just for clarity, the "actual" error is ...
Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at java.desktop/java.awt.AWTEventMulticaster.mouseMoved(AWTEventMulticaster.java:337)
at java.desktop/java.awt.AWTEventMulticaster.mouseMoved(AWTEventMulticaster.java:337)
So looking through the code...
public void assign() {
int randomButton = this.clickMeGenerator();
theChosenButton = buttons[randomButton];
theChosenButton.addMouseMotionListener(new MouseHover());
theChosenButton.setText("Click me");
}
You are repeatedly add a new MouseMotionListener to you buttons, over and over again, and...
public void removeListener() {
theChosenButton.removeMouseMotionListener(new MouseHover());
//}
}
is pointless, as you're trying to remove a new instance of MouseHover from the button, but it will never have been applied in the first place.
The first thing I would do is create an instance of MouseHover as an instance field in Game
private MouseHover mouseHover = new MouseHover();
and use it when calling addMouseMotionListener and removeMouseMotionListener.
I would then, remove the listener from the "currently" active button before adding it to the next one.
Personally, I would do this in the assign method
public void assign() {
int randomButton = this.clickMeGenerator();
if (theChosenButton != null) {
theChosenButton.removeMouseMotionListener(mouseHover);
}
theChosenButton = buttons[randomButton];
theChosenButton.addMouseMotionListener(mouseHover);
theChosenButton.setText("Click me");
}
I would also ensure that assign is called from within the Event Dispatching Thread when the class is first created, as the UI has been realised by the end of the constructor of Game, meaning the first call to assign is outside of the context of the EDT, which is not recommended.
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
Game myGame = new Game();
myGame.assign();
}
});
}
I am making a Pong program, and I have a start button that begins to draw everything, and quite literally to get the ball rolling (you're welcome for the pun). Anyways, when I hit the start button, a Key Listener to move the paddles won't work unless I click the mouse somewhere on the canvas to give it priority. Is there some sort of code to automatically "click" on the canvas without the user being hassled to do so? Thanks in advance.
This Is running awt by the way. I realize I should learn swing, but never got around to it.
public class Pong extends Applet implements ActionListener, KeyListener
{
Canvas c1;
Graphics myG;
Button start;
ball ball;
paddle LPaddle;
paddle RPaddle;
public void init()
{
this.setSize(1300,700);
c1 = new Canvas();
add(c1);
c1.addKeyListener(this);
c1.setBackground(Color.pink);
start = new Button("Start");
add(start);
start.addActionListener(this);
ball = new ball();
LPaddle = new paddle();
RPaddle = new paddle();
myG = c1.getGraphics();
}
public void paint(Graphics g)
{
c1.setLocation(0,0);
c1.setSize(1251,700);
start.setLocation(1255,350);
start.setSize(40,20);
}
public void keyPressed(KeyEvent e)
{
if(e.getKeyCode()==KeyEvent.VK_UP)//up
{
RPaddle.erasePaddle(myG);
RPaddle.movePaddleUp();
RPaddle.drawPaddle(myG);
}
if(e.getKeyCode()==KeyEvent.VK_DOWN)//down
{
RPaddle.erasePaddle(myG);
RPaddle.movePaddleDown();
RPaddle.drawPaddle(myG);
}
if(e.getKeyCode()==KeyEvent.VK_W)
{
LPaddle.erasePaddle(myG);
LPaddle.movePaddleUp();
LPaddle.drawPaddle(myG);
}
if(e.getKeyCode()==KeyEvent.VK_S)
{
LPaddle.erasePaddle(myG);
LPaddle.movePaddleDown();
LPaddle.drawPaddle(myG);
}
if(e.getKeyCode()==KeyEvent.VK_ENTER)
{
myG.drawLine(625,0,625,700);
LPaddle.setInitial(150,0,350);
RPaddle.setInitial(150,1250,350);
LPaddle.drawPaddle(myG);
RPaddle.drawPaddle(myG);
}
}
public void keyReleased(KeyEvent e)
{
}
public void keyTyped(KeyEvent e)
{
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==start)
{
myG.drawLine(625,0,625,700);
LPaddle.setInitial(150,0,350);
RPaddle.setInitial(150,1250,350);
LPaddle.drawPaddle(myG);
RPaddle.drawPaddle(myG);
}
}
KeyListeners are low level interfaces which have a major, significant draw back: The componet they are registered to must be focusable and be focused.
By clicking the start button, you are giving the button focus.
You could call requestFocusInWindow on the instance of the canvas, but this assumes that the the canvas is focusable in the first place.
If you can, you'd be better of using a JComponent/JPanel as the base for your game canvas and use the key bindings API.
I have (what should be) a simple problem to tackle and I'm open to other ways to solve it. I am open to other solutions.
The problem:
We are using java swing to display the graphics of a turn-based, tile-based game. I'm using jlabels with icons, absolutely positioned.
To animate the movement, I am using a swing timer that updates the location by 4 pixels at a time, slowly moving the sprite right, left, etc.
To achieve this initially, I was running a timer, which works wonderfully. The problem comes in when I try to move down, then move right.
The sprite moves down, never moves right, and if I watch the execution with some console printing, it's clear to see that both timers are running at the same time. I've done a fair amount of digging on the internet and I wasn't able to find a way to tell a swing timer not to execute until the first timer has stopped, and if I try to busy-wait until one timer finishes (yuck) the UI never displays at all (clearly a step in the wrong direction.)
Now I can convert away from timers altogether and either have the sprite teleport to its new location, or use some awful busy-wait movement scheme, but I'm hoping some kind soul has a solution.
In short: I need a way to run a swing timer for a set period of time, stop it, and then start a new timer, so that they do not overlap. Preferably this method would allow each timer to be in its own method, and I could then call the methods one after the other.
Thanks in advance for any advice you might have.
Edit: Expanded example code. If a full scsse is a requirement for your advice then I'm sorry to have wasted your time, because the full code is a beast. This sample code does not work at all as it stands, sorry, but it should illustrate the point.
So. We have two functions, each with a timer that runs an animation cycle, one for moving down and right diagonally, one for moving straight down.
public class TestClass {
static int counter = 0;
static int counter2 = 0;
static Timer timerC;
static Timer timerX;
public static void main(String[] args) {
moveC();
moveX();
}
public static void moveC() {
int delay = 200; // milliseconds
timerC = new Timer(delay, null);
timerC.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (counter < 32) {
counter = counter + 4;
System.out.println("*C*");
} else {
timerC.stop();
System.out.println("*C STOP*");
}
}
});
timerC.start();
}
public static void moveX() {
int delay = 200; // milliseconds
timerX = new Timer(delay, null);
timerX.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (counter < 32) {
counter = counter + 4;
System.out.println("*X*");
} else {
timerX.stop();
System.out.println("*X STOP*");
}
}
});
timerX.start();
}
}
What I would want to see here eventually would be
*C*
*C*
*C*
*C*
*C STOP*
*X*
*X*
*X*
*X*
*X STOP*
What I actually get is
*C*
*X*
*C*
*X*
*C*
*X*
*C*
*X*
*C STOP*
*X STOP*
The point I'm trying to get at here is running one animation cycle to completion, then the other.
Thanks again.
Don't use multiple Timers, but rather only one Timer that deals with each direction as it's needed. You need some type of queue to hold the direction information, either a formal queue or a collection that you use as a queue (first in, first out), and then have your Timer extract the direction from this queue as it's running. For example, here I use my JList's model as my queue by removing and using the Direction that was added first (at the top of the JList):
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;
public class TimerPlay extends JPanel {
private DefaultListModel directionJListModel = new DefaultListModel();
private JList directionJList = new JList(directionJListModel);
JButton startTimerButton = new JButton(
new StartTimerBtnAction("Start Timer"));
public TimerPlay() {
ActionListener directionBtnListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent actEvt) {
String actionCommand = actEvt.getActionCommand();
Direction dir = Direction.valueOf(actionCommand);
if (dir != null) {
directionJListModel.addElement(dir);
}
}
};
JPanel directionBtnPanel = new JPanel(new GridLayout(0, 1, 0, 10));
for (Direction dir : Direction.values()) {
JButton dirBtn = new JButton(dir.toString());
dirBtn.addActionListener(directionBtnListener);
directionBtnPanel.add(dirBtn);
}
add(directionBtnPanel);
add(new JScrollPane(directionJList));
add(startTimerButton);
}
private class StartTimerBtnAction extends AbstractAction {
protected static final int MAX_COUNT = 20;
public StartTimerBtnAction(String title) {
super(title);
}
#Override
public void actionPerformed(ActionEvent arg0) {
startTimerButton.setEnabled(false);
int delay = 100;
new Timer(delay, new ActionListener() {
private int count = 0;
private Direction dir = null;
#Override
public void actionPerformed(ActionEvent e) {
if (count == MAX_COUNT) {
count = 0; // restart
return;
} else if (count == 0) {
if (directionJListModel.size() == 0) {
((Timer)e.getSource()).stop();
startTimerButton.setEnabled(true);
return;
}
// extract from "queue"
dir = (Direction) directionJListModel.remove(0);
}
System.out.println(dir); // do movement here
count++;
}
}).start();
}
}
private static void createAndShowGui() {
TimerPlay mainPanel = new TimerPlay();
JFrame frame = new JFrame("TimerPlay");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
enum Direction {
UP, DOWN, LEFT, RIGHT;
}
For reference, this example manages four instances of Timer, two of which run (interleaved) while hovering in any corner. You might compare it to your approach. This related answer discusses animation in a similar tile-based game.
put all Icons in some form of array
create a single Swing Timer with a short delay
in Swing ActionListener, take each `Icon from the array, getBounds from screen, move Icon one step
repeat until target reached.
I'm learning Java, and now that I'm over the packages hump, things are going smoothly. I can draw similarities between most things I'm learning with things I already know at least the concept of. But what on earth is going on with the following bit of code? Is it some form of constructor, or anonymous object?
Something obj = new Something()
{
private static final int num = 3;
public void meth()
{
// w/e
}
};
You got it - this creates an anonymous inner class of Something.
See also: Nested Classes (The Java Tutorial) and Anonymous Classes.
/**
* Notice there's only one thing in this that isn't defined:
* It still needs public abstract void triggerEvent();
*/
public abstract static class TopButton extends JPanel implements MouseListener {
protected ButtonPanel parent;
private String text;
public TopButton(ButtonPanel bp, String text) { parent = bp; this.text = text; addMouseListener(this); }
public void mouseClicked(MouseEvent e) { triggerEvent(); }
public void mouseEntered(MouseEvent e) { }
public void mouseExited(MouseEvent e) { }
public void mousePressed(MouseEvent e) { }
public void mouseReleased(MouseEvent e) { }
public abstract void triggerEvent();
public void paintComponent(Graphics g) {
super.paintComponent(g);
Color oldColor = g.getColor();
Font oldFont = g.getFont();
Font newFont = new Font(oldFont.getName(),oldFont.getStyle(),oldFont.getSize());
g.setFont(newFont);
g.setColor(Color.black);
g.drawString(text, 20, 20);
g.setFont(oldFont);
g.setColor(oldColor);
}
}
Now, when I actually define my buttons, I do this. By providing the one line it needs, the only thing that makes it different from others. Now I could make a new file for each one, and define a new class for each one. This is much simpler.
private static void loadButtonPanelButtons() {
/* This button should tell the parent to bring up the save screen */
TopButton save = new TopButton(buttonPanel,"Save") {
public void triggerEvent() { parent.triggerSave(); }
};
save.setBorder(LineBorder.createBlackLineBorder());
buttonPanel.add(save);
/* This button should tell the parent to bring up the load screen */
TopButton load = new TopButton(buttonPanel,"Load") {
public void triggerEvent() { parent.triggerLoad(); }
};
load.setBorder(LineBorder.createBlackLineBorder());
buttonPanel.add(load);
TopButton addTile = new TopButton(buttonPanel,"Add Tile") {
public void triggerEvent() { parent.triggerAddTile(); }
};
addTile.setBorder(LineBorder.createBlackLineBorder());
buttonPanel.add(addTile);
TopButton saveTiles = new TopButton(buttonPanel,"Save Tiles") {
public void triggerEvent() { parent.triggerStyleSave(); }
};
saveTiles.setBorder(LineBorder.createBlackLineBorder());
buttonPanel.add(saveTiles);
}
Now, when I handle the buttons being pressed, remember back in the definition of TopButton... there was
public void mouseClicked(MouseEvent e) { triggerEvent(); }
We know triggerEvent() eventually gets defined. We can define it on a per-button basis, and when the panel gets clicked, no matter what we defined triggerEvent() to be, it gets called.
Such construct creates an anonymous inner class of a class where this construct is executed, and derived from Something (not an inner class of Something).
The idea is to quickly provide implementations for abstract classes, interfaces, or override some functionality of a class.
(new Thread(){ public void run() { System.out.println("executed on another thread"); }}).start();