I have a class Game which extends JFrame and create the window I want to paint on. Then I have this class Diewhich paints what I want. From Game I can just call the setup() method in the Die class, but how do I then call the paint() method?
public class Die
{
private int xA, yA;
private int dieNumber;
public void setup(int someX, int someY, int someValue) {
dieNumber = someValue;
xA = someX;
yA = someY;
}
public void paint(Graphics pane) {
drawBlank(pane);
if (dieNumber == 1){
drawOne(pane); }
else if (dieNumber == 2){
drawTwo(pane); }
else if (dieNumber == 3){
......
It is a far more better approach if your die extends JPanel and make the custom drawing overriding the paintComponent:
public class Die extends JPanel
{
private int xA, yA;
private int dieNumber;
public void setup(int someX, int someY, int someValue) {
dieNumber = someValue;
xA = someX;
yA = someY;
}
#Override
public void paintComponent(Graphics pane) {
super.painComponent(pane);
if (dieNumber == 1){
drawOne(pane); }
else if (dieNumber == 2){
drawTwo(pane); }
else if (dieNumber == 3){
......
}
You would likely do your graphics in the protected void paintComponent(Graphics g) method override of a JPanel, and inside that method, call die.paint(g) on any Die objects that you need to draw.
e.g.,
class DrawingPanel extends JPanel {
private Die die1 = new Die();
private Die die2 = new Die();
//.....
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
die1.paint(g);
die2.paint(g);
}
}
For more specific and detailed help, please try to create and post a minimal example program or MCVE, a small program that we can run and compile and that will show us your problem. There's a lot of pertinent code that you still need to show us -- but without showing us too much code, which is where the MCVE will help.
Also never do graphics in a JFrame's or Frame's paint method, and you shouldn't use Frame or AWT components anyway. Please read the Swing Graphics tutorials before going forward with this. With regards to why you can't call paint from setup -- Swing graphics are passive and cannot be called on command. You should instead do as I recommend, and suggest to the paint managher that painting be done by calling repaint() on the JPanel. But again, this is explained in the tutorial that you have not yet read. So first and foremost, fix this -- read the tutorial.
Swing tutorials can be found from this link: Swing Info.
Related
I am working on a 2d game using Swing. Before, I used to render my objects and player on a jPanel over the
panel.repaint();
method and would override the paint methode in the panel class. Then I learned about the concept of moving the render code to a Render class which looks like this:
public class Renderer{
public void render(Graphics g, Game game){
game.getObjects.forEach(gameObject -> g.drawImage(....);
}
}
With that code there is always a drawing on a drawing, ....
The problem with this is that I can't (or don't know how to) call the super method repaint() of the panel.
I would like to keep the Render class because the code is much more structured. Any advice on how to reset a jPanel?
I tried using panel.repaint() before calling the render method but I just got a blank screen.
public class Renderer {
public void render(Game game, Graphics graphics) {
Player player = game.getPlayer();
graphics.drawImage(player.getImage(), (int)player.getPosition().getX(), (int)player.getPosition().getY(), null);
}
}
public class Game{
private static Game instance;
private GamePanel gamePanel;
private Player player;
private Renderer renderer;
private boolean isRunning = true;
private final int MAX_FPS = 60;
private Game() {
initialize();
startGameLoop();
}
private void initialize() {
renderer = new Renderer();
player = Player.getInstance();
gamePanel = GamePanel.getInstance(this);
GameWindow.getInstance(gamePanel);
}
private void startGameLoop() {
double timePerCycle = 1_000_000_000 / MAX_FPS;
int updates = 0;
long lastInfo = System.currentTimeMillis();
long timeBefore = System.nanoTime();
while(isRunning) {
if(System.nanoTime() - timeBefore >= timePerCycle) {
timeBefore = System.nanoTime();
update();
render();
updates++;
}
if(System.currentTimeMillis() - lastInfo >= 1000) {
System.out.printf("UPS: %d\n", (updates / (( System.currentTimeMillis() - lastInfo) / 1000)));
lastInfo = System.currentTimeMillis();
updates = 0;
}
}
}
private void render() {
Graphics graphics = gamePanel.getGraphics();
renderer.render(this, graphics);
graphics.dispose();
}
To clear the panel you can employ a boolean in paintComponent and fill in the rectangle via g.fillRect(x,y, width, height).
Her is one possible example. Where boolean clearScreen is an instance field.
public void clear() {
clearScreen = true; // tested in paintComponent
repaint();
clearScreen = false;
}
Here are some other suggestions.
don't override paint for JPanel. Use paintComponent.
first statement should be super.paintComponent(g). This is what allows panel.setBackground() to work, among other things as it calls the overridden method to perform additional functionality.
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
// your stuff here
}
Use a Swing Timer for controlling repaint cycles.
painting and event handling are done in the EventDispatch thread. So processing should be kept to a minimum. Any computations required for your game should be done outside that thread and when possible, only the actual invocation of the graphics methods should be done in the paintComponent method.
If done properly, subsequent calls to repaint() will not add to what is there. Each call must redraw everything including changes.
For more information check out How to paint
There are many examples of painting on this site. Search for them using [Swing] and [Graphics] tags. Here is one that employs some of the above. Also note that Swing components enable double buffering by default
I've been working on a small "game" project for a while now and haven't been able to pass a value into my paintComponent method in any way.
Here's my program. I used a boolean test parameter, but the paintComponent method does not consider test to be true and not paint the blue square.
How can I fix this? Any help would be greatly appreciated.
Class 1 (Swing):
package swing;
import javax.swing.*;
import javax.*;
import java.awt.*;
import java.awt.event.*;
public class swing {
private static draw object = new draw();
public static void main(String[] args) {
JFrame frame = new JFrame("RogueLikeLike MVP");
frame.setVisible(true);
frame.setFocusable(true);
frame.setSize(500,500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);;
frame.add(object);
}
static class Move implements KeyListener{
public boolean isFocusTraversable ( ) {
return true;
}
public void keyPressed(KeyEvent e) {
int x = 10;
int y = 10;
char c = e.getKeyChar();
if(c == 's')
y+=10;
if(c == 'a')
x-=10;
if(c == 'w')
y-=10;
if(c == 'd')
x+=10;
object.setAlignmentX(x);
object.setAlignmentY(y);
}
public void keyReleased(KeyEvent e) {}
public void keyTyped(KeyEvent e) {}
}
}
Class 2 (draw):
package swing;
import javax.swing.*;
import java.awt.*;
public class draw extends JPanel
{
boolean test = true;
private static final long serialVersionUID = 1L;
/*public void passMethod(draw object) {
int x = (int) object.getAlignmentX();
int y = (int) object.getAlignmentY();
}*/
public void drawing(draw object){
draw thing = new draw();
thing.setX(object.getAlignmentX());
int x = 55;
repaint();
}
private void setX(float alignmentX) {
setX((int) alignmentX);
}
private void setY(float alignmentY) {
setY((int) alignmentY);
}
public void paintComponent(Graphics g, boolean test){
super.paintComponents(g);
//int x = (int)object.getAlignmentX();
//int y = (int)object.getAlignmentY();
if(test==true)
{
g.setColor(Color.blue);
g.fillRect(getX(),getY(),100,100);
}
}
}
paintComponent can be overloaded, but the overloaded version won't be used to paint the Component. Actually paintComponent isn't called by the user, but by the painting routine. Instead of overloading the method you should consider using a variable for test and reading/updating this variable.
Like this:
private boolean test = true;
#Override
public void paintComponent(Graphics g){
super.paintComponent(g);
if(test){
//the rest of the code
}
}
Short answer, you can't. This isn't how method overriding works.
paintComponent is one of the documented methods used by the painting sub system to allow you to plugin custom painting, in order to work it MUST match a very particular method signature, otherwise, how would the API know what to call
Instead, paintComponent should paint the current known state of the component, either directly or indirectly.
What this means is, you component should either have a set of properties which the paintComponent method can access or some other object (ie a model) which it can use to determine the current state of which to paint.
You could use a delegate approach, which would allow to define a contract (maybe via a interface) which paintComponent could call, passing the information you need to these delegates, in order for them to perform the required painting.
See Painting in AWT and Swing and Performing Custom Painting for more details about how painting works
nb:
Add the #Override annotation above your paintComponent method, the compiler will error telling you that their is no matching method which supports your signature
Call super.paintComponent NOT super.paintComponent"s", this would set up a recursive call which would result in a StackOverflowError
Problem:
Main.repaint() doesn't work for me. repaint() doesnt invoke my paint method in Main. I've tried calling validate before repainting but with no succes. Main paints perfectly initially or when resized but when i call repaint() in my code nothing is happening.
Here is how the program looks so far link
So im trying to create a level selection screen for a game in java. My game is a JApplet. I have a structure as follows:
my Main class which extends JApplet and contains an object of
LevelScreen class
LevelScreen has a paint method which Main invokes.
I tried to avoid using Swing since the layout managers gave me trouble with the design. So I've tried to make a structure which were simpler and more suited for my need.
paint() in Main.java
public class Main extends JApplet {
public static final int WIDTH = 700, HEIGHT = 500;
private static Main instance;
private LevelScreen levelScreen = new LevelScreen();
private View view = View.LEVELSCREEN;
public static Main getInstance() {
if (instance == null)
instance = new Main();
return instance;
}
#Override
public void init() {
setSize(WIDTH, HEIGHT);
addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent e) {
Point p = e.getPoint();
if (view == View.LEVELSCREEN) {
levelScreen.mouseMoved(p);
}
}
});
}
#Override
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
if (view == View.LEVELSCREEN)
levelScreen.paint(g2);
}
public enum View {
GAME, LEVELSCREEN;
}
}
In the code of my Buttons i try to repaint Main because i want to make a fade out animation when mouse leaves the button. my problem is that i cant invoke the paint(Graphics g) in main with repaint()
Here i call repaint():
public void mouseExited() {
//start new thread to make fade out animation when mouse leave
mouseOver = false;
TimerTask task = new TimerTask() {
#Override
public void run() {
while (!mouseOver && opacity > 0.6) {
opacity -= 0.02;
//set level to 999 so i can see if the game repaints()
level = 999;
Main.getInstance().repaint(); //this doesnt work!!
try {
Thread.sleep(20);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
};
new Thread(task).start();
}
This is a problem with the way that you implement the singleton design pattern. The way you do it doesn't work for an applet, where the instance is created for you by the applet container. You can fix it by changing getInstance as follows:
public Main getInstance() {
return instance;
}
And add this line to the init method:
instance = this;
By the way, you should not override paint in a Swing component, which a JApplet is. You should override paintComponent instead, and call super.paintComponent(g) as the first line. This should fix the problem.
Main.getInstance().repaint(); //this doesnt work!!
I'm not surprised. You're not the one creating the instance of the JApplet, the browser is.
When you call this...
public static Main getInstance() {
if (instance == null)
instance = new Main();
return instance;
}
You are actually creating a second instance of the applet, which is NOT the one that is on the screen, so when you call repaint, Swing goes, "no point, you're not even displayable" and does nothing.
Without any more context of you code, you may not even need getInstance, instead reference the current instance using Main.this instead.
You should also consider taking a look at Performing Custom Painting.
Top level containers like JAppelt are not double buffered, which involves more work to paint directly to them. Instead, move your application to be based on something like a JPanel and override it's paintComponent method instead.
Painting is also a complex, multi-layered scheme. You MUST call super.paintXxx in order to preserve the paint chain and prevent any possible issues.
I'm trying to call repaint from another class. But it does not work. I have to draw on a frame.
public class Tester extends JFrame{
public static dtest d ;
public static void main(String[] args) {
Tester t = new Tester();
d = new dtest();
test tnew = new test();
}
public static class dtest extends JFrame implements MouseMotionListener{
public static int x,y;
dtest()
{
super("title");
setSize(500,500);
setVisible(true);
addMouseMotionListener(this);
}
#Override
public void mouseDragged(MouseEvent e) {
x = e.getX();
y = e.getY();
repaint();
}
#Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
public void paint(Graphics g)
{
System.out.println("I am called");
}
}
public static class test {
public test()
{
for(int i = 0 ; i < 5 ; i++)
{
System.out.println("I am called from run");
d.repaint();
}
}
}
}
this prints
I am called from run
I am called from run
I am called from run
I am called from run
I am called from run
so it does not executing the paint() portion. d.repaint() is not working. why?
Take a look at this page and look at the first answer. It's a similar if not exact question to yours.
JFrame's paint() method has been deprecated. The compiler, or your IDE, should be complaining a bit, especially if you place the #Override tag directly above the method (use this to test if this method can be rewritten... aka what you're trying to do).
This means that its use has been discouraged and some functionality may have been removed. When using javax.swing, you'll want to learn the system completely about JPanels and JComponents. To paint something on a screen, you'll want to add a custom class that extends JPanel with the add(Component c) method. Then, override the paintComponent(Graphics g) method in that class. Make sure to have the first line in that method be super.paintComponent(g); so that the window can refresh itself.
For completeness:
public class MyWindow extends JFrame {
MyPanel thePanel;
public MyWindow(int x, int y) {
setSize(x, y);
thePanel = new MyPanel(x, y);
this.add(thePanel);
}
}
public class MyPanel extends JPanel {
public MyPanel(int x, int y)
setSize(x, y);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(ImageManager.getImage("Cute Puppy"), 40, 40, null); // Or whatever
}
}
So, when the repaint() or revalidate() method is called on the MyWindow, the Panel will recieve a paintComponent call.
Please let me know in the comments if you need any additional help.
Edited:
Since you need to use MouseMotionListener, and I'm still not quite understanding the context and trouble of "I need to call repaint from another class"... I will try my best.
Firstly, check out this tutorial on the Oracle pages. Also, check out the others on GUI's. You'll learn a lot about organization and displaying that will make you realize how their system can work with yours.
Now, for your questions:
i have to use MouseMotionListener.
Not quite... it is a good way for set up but you can run a Thread (something that constantly runs methods over and over) to check the Mouse coordinates. You'll want to start doing this when you get into games and other miscellaneous applications.
new Thread() {
public void run() {
Point mouse;
int mousex;
int mousey;
while (true) {
mouse = MouseInfo.getPointerInfo().getLocation();
mousex = mouse.x - theWindow.getLocationOnScreen().x - 3; // You'll need to get the
// x coordinate, subtract the window's x coordinate, and subtract 3 because of
// the blue border around a standard pc window.
mousey = mouse.y - theWindow.getLocationOnScreen().y - 29; // 29 is top bar height
SomeOtherClass.processMove(mousex, mousey);
}
}
}.start();
Next: I tried that with JPanel but i could not do that. If you read the tutorial at the top of my edit, you see they implement MouseMotionListener with ease.
Next: I prefer to do it with JFrame. If you wish to process the mouse in the JFrame, do the following: Have your JFrame the listener, but the JPanel be where the mouse data comes from. As follows:
public class MyWindow extends JFrame implements MouseMotionListener {
public MyPanel thePanel;
public int x;
public int y;
public MyWindow() {
thePanel = new MyPanel();
thePanel.addMouseMotionListener(this);
// Make this JFrame get called when the mouse
// moves across the panel.
}
#Override
public void mouseDragged(MouseEvent e) {
x = e.getX();
y = e.getY();
thePanel.repaint();
}
#Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
}
public class MyPanel extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
// Other painting stuff
}
}
Next: Now i have to update the frame from another class. I could not find a way to update the GUI(the frame) from another class.
Simple. Since the JPanel is what needs to be updated, add the following method to the MyWindow class:
public void repaintWindow() {
thePanel.repaint();
}
And add this to whenever you need to update it:
MyWindow theWindow = new MyWindow();
theWindow.repaintWindow();
Next: all the answers here extended JPanel. So i could not find my answer.
I apologize, but you NEED a panel. It is possible to do with JFrames, but if you want to start doing things raw and low-level, you need to learn how these things work by learning to read the oracle tutorials and the oracle documentation. For now, use JPanels in any ways I've shown you.
Next: from another class I have to draw something on JFrame.Is that possible?
Yes, indeed! Whenever you want to draw something:
MyWindow theWindow = new MyWindow();
Graphics g = theWindow.thePanel.getGraphics();
BufferedImage someRandomImage = SomeRandomClass.getRandomImage();
g.drawImage(someRandomImage, 200, 481, null);
theWindow.repaintWindow();
I really hope I've helped but to program in java you need to use the tools they give you, especially when it comes to high level things like Swing. There are tutorials everywhere for this stuff. Please read them before asking for specific help in the future.
I have a custom, abstract class 'Panel' which extends JPanel. There aren't many differences with the two when painting. I have a Panel and I'm simulating an animation by updating the x value of an image. I have two animations right now, one that properly repaints and another than does not. This is for the one that does not. The one that works will be labelled A, the one that doesn't will be B.
A and B follow the same format. Update some variable on the Panel, calls update (a method in Panel which calls PaintComponent) and then calls repaint. It calls repaint after because this issue was with A before and was solved that way.
A: Updates an image variable.
B: Updates the x variable of an image.
The Problem: The repaint doesn't clear the old image location and so it's a choppy mess across the screen.
What I've tried:
I've seen the super.PaintComponent(g) mentioned a lot, but this
hasn't solved the problem.
I've tried changing the order for when the repaint/update methods are
called.
Repaint does not update the Panel at all. (Probably because the
painting is done in PaintComponent)
Any help would be appreciated.
Code:
Panel:
public Panel (boolean visible){
super();
this.setLayout(new BorderLayout(640, 416));//sets the Layout type of the panel
this.setOpaque(false);//Makes it so that the panel underneath can be seen where images aren't drawn
this.setVisible(visible);
ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
gs = ge.getDefaultScreenDevice();
gc = gs.getDefaultConfiguration();
}
public void paintComponent (Graphics g){
setUp();
drawOff();
setDown(g);
}
private void setUp(){
off_screen = gc.createCompatibleImage(getSize().width, getSize().height, Transparency.TRANSLUCENT);
buffer = off_screen.createGraphics();
}
protected abstract void drawOff();
private void setDown(Graphics g){
g.drawImage(off_screen,0,0,this);
off_screen.flush();
}
public void update(){
paintComponent(this.getGraphics());
}
Animation Methods (mg is the panel in question):
private void battleStart(User user) {
for (int i = 0; i < user.battle.length; i++) {
mg.battleStart(user.battleStart(i));
mg.update();
try {
Thread.sleep(150);
} catch (Exception e) {
}
mg.repaint();
}
}
private void animateStart(User user){
for (int i = 0; i < 10; i++){
mg.x = mg.x + 10;
mg.update();
try {
Thread.sleep(100);
} catch (Exception e) {
}
mg.repaint();
}
}
I think your design is way off and that is why things are not working. I'm not quite sure how your non-abstract JPanels work, but consider making your parent JPanel something more along these lines:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class MyPanel extends JPanel {
private GraphicsEnvironment ge;
private GraphicsDevice gs;
private GraphicsConfiguration gc;
private BufferedImage offScreen;
public MyPanel(boolean visible) {
super();
this.setLayout(new BorderLayout(640, 416)); // strange constants for this layout.
this.setOpaque(false);
this.setVisible(visible);
ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
gs = ge.getDefaultScreenDevice();
gc = gs.getDefaultConfiguration();
addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
setUp();
}
});
}
#Override
// don't make this public. Keep it protected like the super's
// just draw in this method. Don't call other methods that create buffers
// or draw to buffers.
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (offScreen != null) {
g.drawImage(offScreen, 0, 0, null);
}
}
private void setUp() {
offScreen = gc.createCompatibleImage(getSize().width, getSize().height,
Transparency.TRANSLUCENT);
}
// draw to the buffer outside of the paintComponent
// and then call repaint() when done
public void upDateOffScreen() {
// ?? offScreen.flush(); // I've never used this before,
// so am not sure if you need this here
Graphics2D osGraphics = offScreen.createGraphics();
// TODO: do drawing with osGraphics object here
osGraphics.dispose();
repaint();
}
}
Also and again,
Do all long processing methods off of the EDT (Event Dispatch Thread).
Never call Thread.sleep(...) on the EDT.
Consider using Swing Timers instead of using Thread.sleep for the animations.
It's OK to call repaint on your JPanel off of the EDT, but for the most part that's about it.
All other Swing methods should be called on the EDT.
Read, re-read, and study the 2D and Swing graphics tutorials.