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JFrame repaint() and revalidate() only updating when window is resized on Mac os

I use this class for my school app projects. It is how I set the application up and it extends JFrame and implements Runnable. Now whenever I use this in school on a Windows computer and everything works and the screen updates, but at home on a Mac it doesn't. I use Eclipse neon with JDK 1.8.0_101
Please help me out, I can't test any projects at home cause of this.
import java.awt.Graphics;
import javax.swing.JFrame;
public abstract class GUIApplication extends JFrame implements Runnable{
private Screen currentScreen;
//no main, cant instentiate an abstract class
public GUIApplication(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int x=40;
int y=40;
int width=1000;
int height=640;
setBounds(x,y,width,height);
initScreen();
setVisible(true);
}
//this is a method for creating the starting screen
protected abstract void initScreen();
public void setScreen(Screen screen){
//stop controls from previous screen
removeListeners();
setCurrentScreen(screen);
//add new controls
addListeners();
}
private void removeListeners(){
if(getCurrentScreen() != null){
if(getCurrentScreen().getMouseListener() != null) removeMouseListener(getCurrentScreen().getMouseListener());
if(getCurrentScreen().getMouseMotionListener() != null) removeMouseMotionListener(getCurrentScreen().getMouseMotionListener());
if(getCurrentScreen().getKeyListener() != null) removeKeyListener(getCurrentScreen().getKeyListener());
// if(currentScreen.getMouseWheelListener() != null) removeMouseWheelListener(currentScreen.getMouseWheelListener());
}
}
private void addListeners(){
if(getCurrentScreen() != null){
if(getCurrentScreen().getMouseListener() != null)addMouseListener(getCurrentScreen().getMouseListener());
if(getCurrentScreen().getMouseMotionListener() != null) addMouseMotionListener(getCurrentScreen().getMouseMotionListener());
if(getCurrentScreen().getKeyListener() != null){
addKeyListener(getCurrentScreen().getKeyListener());
}
// if(currentScreen.getMouseWheelListener() != null) addMouseWheelListener(currentScreen.getMouseWheelListener());
}
}
public void paint(Graphics g){
g.drawImage(getCurrentScreen().getImage(), 0, 0, null);
}
public void run(){
while(true){
getCurrentScreen().update();
repaint();
try {
Thread.sleep(30);
repaint();
revalidate();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public Screen getCurrentScreen() {
return currentScreen;
}
public void setCurrentScreen(Screen currentScreen) {
this.currentScreen = currentScreen;
}
}
This is how a game would start:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.util.ArrayList;
import javax.swing.JFrame;
import game.mainScreenTeam.Dragon;
import game.mainScreenTeam.HomeScreen;
import game.miniGameTeam.GameInstructions;
import game.miniGameTeam.GameScreen;
import game.miniGameTeam.HighScoreScreen;
import game.shopScreen.BuyScreenWendy;
import game.shopScreen.HomeShopScreen;
import game.shopScreen.SellShopZheng;
import guiPractice.GUIApplication;
import guiPractice.Screen;
import guiPractice.components.AnimatedComponent;
/**
* #author Kat
*
*/
public class DragonLand extends GUIApplication {
public static DragonLand game;
public static int coins = 1500;
public static HomeScreen homeScreen;
public static Screen shopMain; // shop 1
public static Screen sellScreen; // shop 2
public static Screen buyScreen; // shop 3
public static Screen highscoreScreen; // high score
public static GameScreen miniGameScreen; // minigame
public static Screen gameInstructionsScreen;
public static Screen HelpScreen;
public static Color NAVY;
public static Color BRIGHT_PINK;
public static Color LIGHT_PINK;
public static Color LIGHT_NUDE;
public static Color DARKER_NUDE;
/**
*
*/
// public static void addDragon(AnimatedComponent a){
// dragonList.add(a);
// }
public DragonLand() {
}
/* (non-Javadoc)
* #see guiPractice.GUIApplication#initScreen()
*/
#Override
protected void initScreen() {
initColors();
miniGameScreen = new GameScreen(getWidth(),getHeight());
shopMain = new HomeShopScreen(getWidth(),getHeight());
sellScreen = new SellShopZheng(getWidth(),getHeight());
homeScreen = new HomeScreen(getWidth(),getHeight());
buyScreen = new BuyScreenWendy(getWidth(),getHeight());
highscoreScreen = new HighScoreScreen(getWidth(),getHeight());
HomeScreen.jenCode = new game.mainScreenTeam.HomeJenniber();
gameInstructionsScreen = new GameInstructions(getWidth(), getHeight());
setScreen(homeScreen);
}
private void initColors() {
NAVY = new Color(62,74,99);
BRIGHT_PINK = new Color(224,102,102);
LIGHT_PINK = new Color(248,186,182);
LIGHT_NUDE = new Color(244,215,183);
DARKER_NUDE = new Color(230,195,147);
}
/**
* #param args
*/
public static void main(String[] args) {
game = new DragonLand();
Thread go = new Thread(game);
go.start();
}
//public coin getter + setter
public void setCoins(int x){
coins = x;
}
public int getCoins(){
return coins;
}
}
This is the home screen
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import javax.swing.ImageIcon;
import game.DragonLand;
import guiPractice.ClickableScreen;
import guiPractice.components.Action;
import guiPractice.components.AnimatedComponent;
import guiPractice.components.Button;
import guiPractice.components.Graphic;
import guiPractice.components.TextLabel;
import guiPractice.components.Visible;
import guiPractice.sampleGames.MouseFollower;
/**
* #author Kat
* #author Jenniber
*
*/
public class HomeScreen extends ClickableScreen implements Runnable{
private Graphic background;
public static HomeJenniber jenCode;
public HomeScreen(int width, int height) {
super(width, height);
Thread play = new Thread(this);
play.start();
}
#Override
public void initAllObjects(ArrayList<Visible> viewObjects) {
background=new Graphic(0,0,getWidth(),getHeight(),"img/Grassland.png");
viewObjects.add(background);
HomeKat katCode=new HomeKat(viewObjects, getWidth(), getHeight());
}
#Override
public void run() {
}
}
katCode adds buttons to the screen and image annimations

public void paint(Graphics g){
g.drawImage(getCurrentScreen().getImage(), 0, 0, null);
}
Don't override paint() on a JFrame.
The proper way to do custom painting is to override paintComponent(...) on a JPanel (or JComponent) and then you can set the content pane of the frame to this panel. And don't forget to invoke super.paintComponent(...) as the first statement in the method. Read the section from the Swing tutorial on Custom Painting for more information and working examples.
However if you do get lazy, then at minimum you need to invoke super.paint(...) as the first statement in the paint(...) method.
Also, I doubt you need the revalidate(), since you don't appear to be adding/removing components from the frame.
But in general the order should be:
revalidate(); // to invoke the layout manager
repaint(); // paint components in new location.
I also don't know why you are invoking the update() method. That seems like old AWT code which you don't use in Swing. I suggest you take a look at the tutorial link I gave you and look at the table of contents for other Swing basics.

How do I correctly set up canvas capable on running a simulation

I'm brand new to Java and have only recently learnt about object oriented programming. I'm trying to create a program which can run a simulation, the general idea is that I want a part of the screen dedicated to buttons/sliders and another part to be dedicated the the Canvas running the simulation. For now I'm not worried about the simulation itself, I'm just trying to get some graphics on the canvas (which is smaller than the JFrame).
Here is my code (I'll try to leave some explanation below it)
public class Launcher {
public static void main(String[] args){
Display display = new Display();
}
}
.
import java.awt.*;
import javax.swing.*;
public class Display {
public final int width = 1280, height = 720;
public final int cwidth = 894, cheight = 504;
public final String title = "Mechancis Simulator";
private JFrame frame;
//private JPanel panel;
private Canvas canvas;
private Simulation simulation;
public Display(){
initDisplay();
simulation = new Simulation();
}
private void initDisplay(){
frame = new JFrame(title);
frame.setSize(width, height);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
/*panel = new JPanel();
panel.setSize(width, height);
panel.setLocation(0,0); */
canvas = new Canvas();
canvas.setPreferredSize(new Dimension(cwidth, cheight));
canvas.setMaximumSize(new Dimension(cwidth, cheight));
canvas.setMinimumSize(new Dimension(cwidth, cheight));
canvas.setLocation(width - (cwidth +15), 15);
//panel.add(canvas);
frame.add(canvas);
/* Add code for buttons/sliders/boxes here */
/* Add these to panel */
}
public JFrame getFrame(){
return frame;
}
public Canvas getCanvas(){
return canvas;
}
}
.
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.awt.*;
import javax.swing.*;
public class Simulation extends Display implements Runnable {
private boolean running = false;
private Thread thread;
private BufferStrategy bs;
private Graphics g;
public Simulation(){
}
private void init(){
}
private void tick(){
}
private void render(){
bs = getCanvas().getBufferStrategy();
if(bs == null){
getCanvas().createBufferStrategy(3);
return;
}
g = bs.getDrawGraphics();
//Draw Here!
//End Drawing!
bs.show();
g.dispose();
}
public void run(){
init();
while(running){
tick();
render();
}
stop();
}
public synchronized void start(){
if(running)
return;
running = true;
thread = new Thread(this);
thread.start();
}
public synchronized void stop(){
if(!running)
return;
running = false;
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
When I run the program the window starts going crazy. I'm quite new to classes and threading so maybe that is the problem. I just want to be able to run the simulation after setting up Frame and Canvas in the Display object.
Thanks.

What you're doing basically is this:
class Display {
private final Simulation sim;
public Display() { sim = new Simulation(); }
}
class Simulation extends Display {
public Simulation() { }
}
when you create a new Display the constructor creates a new Simulation which is a Display which creates a new Simulation which is a Display which creates a new Simulation which is a Display which creates a new Simulation...*
So don't. There's no reason for your Simulation to be a display and to own another Simulation. If you want all the control in Display define a constructor that takes as an argument the Simulation it's displaying and give it a simulation when you create it:
class Display {
private final Simulation sim;
public Display(Simulation sim) { this.sim = sim; }
}
class Simulation {
}
...
Display display = new Display(new Simulation());
*I suggest you google for a tutorial on inheritance, if you wish to know more. Here's the tutorial from oracle to get you started: "You can write a subclass constructor that invokes the constructor of the superclass, either implicitly or by using the keyword super." In your code example the constructor super() is invoked implicitly.

Java: Repaint in Swing Not Working

I am learning java swing and am having trouble with the following program. It creates a small frame with a quit button at top. The objective is to display coordinates wherever the mouse is clicked. When I click the mouse 2 unwanted things are happening:
the quit button is overridden by the mouse clicks and it no longer responds (instead of responding to event and quitting, it displays coordinates on top of the quit button).
when I click at a new location, the coordinates from the old location persist.
I used removeAll() and revalidate() before doing repaint() based on this discussion but that has not helped. This code is taken from here and the code to says to research online documentation for why this is happening.
Any pointers?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JLabel;
public class QuitCoordinateTest {
public static void main(String[] args){
GUI gui = new GUI();
}
}
class MyFrame extends JFrame implements ActionListener{
int clickX;
int clickY;
public void paint(Graphics g){
g.drawString("" + clickX + ", " + clickY, clickX, clickY);
}
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
//=======================================================//
class GUI extends MyFrame {
JButton quitButton = new JButton("Quit");
public GUI(){
MyFrame displayWindow = new MyFrame();
displayWindow.setTitle("Title");
/*
JPanel buttonPanel = new JPanel();
buttonPanel.add(quitButton);
displayWindow.getContentPane().add(buttonPanel,BorderLayout.NORTH);
JPanel textPanel = new JPanel();
*/
displayWindow.getContentPane().add(quitButton,BorderLayout.NORTH);
quitButton.addActionListener(displayWindow);
displayWindow.setSize(201,201);
displayWindow.setVisible(true);
// displayWindow.pack();
displayWindow.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
displayWindow.addMouseListener(new MouseProc(displayWindow));
}//end constructor
}//end class GUI definition
//=======================================================//
//This listener class monitors for mouse presses and
// displays the coordinates of the mouse pointer when the
// mouse is pressed on the source object.
class MouseProc extends MouseAdapter{
MyFrame refToWin;
MouseProc(MyFrame inWin){
refToWin = inWin;
}
//Override the mousePressed method to determine and
// display the coordinates when the mouse is pressed.
public void mousePressed(MouseEvent e){
refToWin.removeAll();
refToWin.clickX = e.getX();
refToWin.clickY = e.getY();
//Force the JFrame object to be repainted in order to
// display the coordinate information.
refToWin.removeAll();
refToWin.validate();
refToWin.repaint();
}
}

repaint() is working fine.
Avoid drawing directly on the JFrame.
Instead draw in the protected void paintComponent(Graphics g) method override of a JPanel that is then displayed in your JFrame.
Be sure to call the super's paintComponent(g) method inside of your paintComponent override -- this will erase the old images and is the reason for one of your problems.
Use reasonable comments in your code. Too many comments and too much text distracts and makes understanding your code harder, not easier.
Calling removeAll() on your JFrame will do just that -- remove all components including your button. Why are you calling this? Are you sure that you want to call this method?
A minor nitpick -- you'll want to avoid directly setting the fields of another class, such as your clickX and clickY fields. Instead, make them private, and only allow outside classes to modify them through public methods. While it may not matter much for this small program, it will matter greatly when you start scaling up your programming and create large programs with complex interactions. The key to success here will be to limit and control all communication between classes to avoid hard to detect side effects.
For example, something like...
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
String str = String.format("[%d, %d]", clickX, clickY);
g.drawString(str, clickX, clickY);
}
public int getClickX() {
return clickX;
}
public void setClickX(int clickX) {
this.clickX = clickX;
}
public int getClickY() {
return clickY;
}
public void setClickY(int clickY) {
this.clickY = clickY;
}
For example
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class DetectClicks extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private int clickX;
private int clickY;
public DetectClicks() {
MyMouseListener mouseAdapter = new MyMouseListener(this);
addMouseListener(mouseAdapter);
addMouseMotionListener(mouseAdapter); // to allow dragging!
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
String str = String.format("[%d, %d]", clickX, clickY);
g.drawString(str, clickX, clickY);
}
public int getClickX() {
return clickX;
}
public void setClickX(int clickX) {
this.clickX = clickX;
}
public int getClickY() {
return clickY;
}
public void setClickY(int clickY) {
this.clickY = clickY;
}
private static void createAndShowGui() {
DetectClicks mainPanel = new DetectClicks();
JFrame frame = new JFrame("DetectClicks");
frame.setDefaultCloseOperation(JFrame.DISPOSE_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();
}
});
}
}
class MyMouseListener extends MouseAdapter {
private DetectClicks detectClicks;
public MyMouseListener(DetectClicks detectClicks) {
this.detectClicks = detectClicks;
}
#Override
public void mousePressed(MouseEvent evt) {
showPoint(evt);
}
#Override
public void mouseDragged(MouseEvent evt) {
showPoint(evt);
}
private void showPoint(MouseEvent evt) {
detectClicks.setClickX(evt.getX());
detectClicks.setClickY(evt.getY());
detectClicks.repaint();
}
}

Your event is getting consumed by the handler that prints the coordinates, you need to redispatch the event so that the button can see it. You can do it like this, inside the coordinate display event handler:
Component c = e.getComponent();
c.getParent().dispatchEvent( e );
Also, I'd be tempted to use the glass pane of the frame, and put a JLabel on it with the co-ordinates rather than messing with the paint method.

you don't have to use any of repaint(),invalidate() etc.
i highly recommend to use
SwingUtilities.invokeLater(new Runnable() {
public void run() {
//TODO udpdate UI compontents, layouts etc.
}
});
this guarantees that UI components update on real time. Because we don't know when the system update UI hierarchy so we can't force it. This allow system to determine by it's self.

Manual Positioning of Image in JFrame

I am trying to create a JFrame that displays an image from a file path onto a particular position on the JFrame. At a later time (when a button is clicked), I want the image to move positions, say, 50 pixles to the left. If a layout manager is necessary, I want to use the null layout, as this is a project for myself and I am not quite ready to learn how to write my own layout manager.
So far, I have managed to display a BufferedImage in a frame, but I do not know how to specify its position.
Is using a BufferedImage even the correct approach? What is the best way to go about doing this?
Update: I tried to follow your suggestion of using mouselistener and it resulted in this:
class ImgComponent extends JComponent implements ChangeListener, MouseListener {
MovableImage mi;
public ImgComponent(MovableImage mi) {
this.mi = mi;
mi.addListener(this);
mi.addListener1(this);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(mi.i, mi.getX(), mi.getY(), null);
}
#Override
public void stateChanged(ChangeEvent e) {
repaint();
}
#Override
public void mouseClicked(MouseEvent e) {
mi.setPos(100, 100);
System.out.println("yay");
}
}
But unfortinely, the mouseClicked event never triggers. I just want that damn image to move, lol.

Here's a complete example that uses the model/view/controller pattern. (Just dump all snippets after each other in a single .java file.)
import java.awt.*;
import java.awt.event.ActionEvent;
import java.util.*;
import java.util.List;
import javax.swing.*;
import javax.swing.event.*;
// A class encapsulating an image and a x-coordinate (a "model")
class MovableImage {
Image i = new ImageIcon("duke.png").getImage();
private int x = 0;
// Observers that are interested in movements.
List<ChangeListener> listeners = new ArrayList<ChangeListener>();
public void addListener(ChangeListener cl) {
listeners.add(cl);
}
public int getX() {
return x;
}
public void incrementX() {
x += 10;
// Notify those interested.
for (ChangeListener cl : listeners)
cl.stateChanged(null);
}
}
// A graphical component displaying the model.
// Object of this class are interested in movement because when the image moves,
// this component needs to be repainted.
class ImgComponent extends JComponent implements ChangeListener {
// The movable image to present.
MovableImage mi;
public ImgComponent(MovableImage mi) {
this.mi = mi;
mi.addListener(this);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(mi.i, mi.getX(), 10, null);
}
// This method is called from MovableImage when the position changes.
#Override
public void stateChanged(ChangeEvent e) {
repaint();
}
}
// Main class.
public class FrameTestBase extends JFrame {
public static void main(String args[]) {
// Create the "model".
final MovableImage mi = new MovableImage();
FrameTestBase t = new FrameTestBase();
t.setLayout(new BorderLayout());
// Add a component presenting the model.
t.add(new ImgComponent(mi), BorderLayout.CENTER);
// Create a button which increments x when clicked on.
t.add(new JButton(new AbstractAction("Move right") {
#Override
public void actionPerformed(ActionEvent e) {
mi.incrementX();
}
}), BorderLayout.SOUTH);
// Show it.
t.setDefaultCloseOperation(EXIT_ON_CLOSE);
t.setSize(400, 400);
t.setVisible(true);
}
}
Regarding your edit:
You need to add the mouse listener as well. In the constructor:
public ImgComponent(MovableImage mi) {
this.mi = mi;
mi.addListener(this);
mi.addListener1(this);
}
add the following line at the bottom:
addMouseListener(this);

Where can I put mouse event handling code so that it is out of the way but can still manipulate objects?

I'm learning Java here and trying to get to grips with classes and how best to catch mouse events etc. for my little game, so please be patient and give my some hints.
The main class of my project extends JFrame and upon construction adds to itself an object of a class which extends JPanel. This JPanel covers the whole window and it is this I am using to paint stuff to the screen. Then I have a class called Scene which extends nothing but which stores all the references to the current objects on the screen and is responsible for compiling them all and passing them back to the JPanel. I didn't want to put the full mouse event code in the JPanel because it would be so messy so I though I'd create another class for that called MEs and let each scene have one. My thinking was, this way each mes object can access the objects in each scene easily. So my code is looking like this:
class DPanel extends JPanel {
Scene scCurrent;
public DPanel() {
scCurrent = new Scene();
addMouseMotionListener(new MouseAdapter() {
public void mouseMoved(MouseEvent me) { scCurrent.mes.moved(me); }
});
...
}
...
but of course, inside scCurrent.mes.moved() I don't even know how to change the cursor. It doesn't recognise setCursor() in there. How can I change the cursor and access objects that are higher up the tree like I'd need to to switch scene? Or is there some other place I can tuck my mouse event handling code that will not bumph-out out my JPanel?

You are trying to separate out the control code from the view (GUI) code, and this is a good thing. A solution is to give the view code public methods that allow outside code to change its state, and give the control classes a reference to the view so that the controls (i.e., MouseListeners, MouseMotionListeners, ActionListeneres) can call these methods on a proper reference and change the view's states.
Edit 1
It may be easier just to show you an example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class ViewControl {
private static void createAndShowGui() {
View view = new View();
Control control = new Control(view);
view.addMouseAdapter(control);
JFrame frame = new JFrame("ViewControl");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(view);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class View extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private List<Point> points = new ArrayList<Point>();
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (points.size() > 1) {
for (int i = 0; i < points.size() - 1; i++) {
int x1 = points.get(i).x;
int y1 = points.get(i).y;
int x2 = points.get(i + 1).x;
int y2 = points.get(i + 1).y;
g.drawLine(x1, y1, x2, y2);
}
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public void addMouseAdapter(MouseAdapter adapter) {
// addMouseListener(adapter);
addMouseMotionListener(adapter);
}
public void addPoint(Point p) {
points.add(p);
repaint();
}
}
class Control extends MouseAdapter {
private View view;
public Control(View view) {
this.view = view;
}
#Override
public void mouseDragged(MouseEvent e) {
view.addPoint(e.getPoint());
}
}