Develop Reference

My game is flickering due to my painting directly in JFrame. How do I use JPanel? [duplicate]

I think I need to put some code where the comment is (or maybe use non static method but I am not sure). The main method creates the window and then starts the graphics method. I would like the blue square to flash.
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class paintTest extends JPanel{
private static JFrame theWindow = new JFrame("Window");
static boolean blueSqr = false;
public void paint(Graphics g) {
g.setColor(Color.RED);
g.fillRect(10, 10, 10, 10);
if(blueSqr){
g.setColor(Color.BLUE);
g.fillRect(10, 10, 10, 10);
}
}
public static void main(String[] args){
createWindow();
theWindow.getContentPane().add(new paintTest());
while(true){
blueSqr = false;
System.out.println("off");
try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}
blueSqr = true;
// Needs something here
System.out.println("on");
try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}
}
}
public static void createWindow(){
theWindow.setSize(500, 500);
theWindow.setLocationRelativeTo(null);
theWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
theWindow.setVisible(true);
}
}
Any help would be really good.

Use a Swing Timer to call repaint(). Also, override paintComponent() in a JPanel, rather than paint().
Something like this:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class PaintTest extends JPanel{
boolean blueSqr = false;
PaintTest() {
setPreferredSize(new Dimension(100,25));
ActionListener al = new ActionListener() {
public void actionPerformed(ActionEvent ae) {
blueSqr = !blueSqr;
repaint();
}
};
Timer timer = new Timer(1000,al);
timer.start();
}
public void paintComponent(Graphics g) {
Color c = (blueSqr ? Color.BLUE : Color.RED);
g.setColor(c);
g.fillRect(10, 10, 10, 10);
}
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame theWindow = new JFrame("Window");
theWindow.getContentPane().add(new PaintTest());
createWindow(theWindow);
}
});
}
public static void createWindow(JFrame theWindow){
theWindow.pack();
theWindow.setLocationByPlatform(true);
theWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
theWindow.setVisible(true);
}
}
There were other improvements I could not be bothered documenting (code speaks louder than words). If you have any questions (check the docs first, then) ask.

your issues are
1) by calling Thread.sleep(int) in the Swing related code, never do that, for delaying in Swing (there are lots of topics about why not use sleep in programing languages ...) use Swing Timer
2) your JPanel doesn't returns any XxxSize
3) for Swing use paintComponent(), only if you have got really important reasons then use method paint() more about repaint and animating Graphics in the 2D Graphics tutorial
4) Swing GUI should be built in the Event Dispatch Thread

Close additional window (PApplet)

How to close new frame without exiting whole application?
What is easiest way to do it by clicking X button.
Thanks in advance.
ControlFrame cf;
void setup()
{
cf = new ControlFrame(this,500,500, "cf name");
}
class ControlFrame extends PApplet
{
int w,h;
PApplet parent;
public ControlFrame(PApplet _parent, int _w, int _h, String _name)
{
super();
parent=_parent; w=_w; h=_h;
PApplet.runSketch(new String[]{this.getClass().getName()},this);
}
public void settings()
{ size(w,h); }
}

Note: Your question doesn't really have anything to do with ControlP5.
Step 1: Get a reference to the native window. How you do this depends on the renderer you're using. If you're using the default renderer, it looks like this:
Frame frame = ( (SmoothCanvas) ((PSurfaceAWT)surface).getNative()).getFrame();
Step 2: You can then call dispose() on that Frame to hide it without quititng the entire application.
frame.dispose();
Putting it all together, it looks like this:
import java.awt.Frame;
import processing.awt.PSurfaceAWT;
import processing.awt.PSurfaceAWT.SmoothCanvas;
ControlFrame cf;
void setup()
{
cf = new ControlFrame(this, 500, 500, "cf name");
}
class ControlFrame extends PApplet
{
int w, h;
PApplet parent;
public ControlFrame(PApplet _parent, int _w, int _h, String _name)
{
super();
parent=_parent;
w=_w;
h=_h;
PApplet.runSketch(new String[]{this.getClass().getName()}, this);
}
public void settings()
{
size(w, h);
}
public void draw(){
//needed for mousePressed
println(millis());
}
public void mousePressed(){
Frame frame = ( (SmoothCanvas) ((PSurfaceAWT)surface).getNative()).getFrame();
frame.dispose();
}
}
Step 3: Note that your second sketch will continue running, so you might also want to call noLoop() to prevent unnecessary computation.

Java Graphics Update/Repaint Graphic

I'm trying to work with the Java paint
utility and it's been a bit of a hassle.
I'm trying to do something which I assume is quite basic.
I'm drawing a square Graphic to a JPanel and then trying
to move it using repaint
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
public class testGui {
static gui gc_gui;
static int gv_x;
static int gv_y;
public static void main(String[] args) {
gc_gui = new gui();
gv_x = 50;
gv_y = 50;
gc_gui.cv_frame.setVisible(true);
}
public static class gui {
JFrame cv_frame;
content cv_content;
public gui() {
cv_frame = new JFrame();
cv_frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
cv_frame.setTitle("Test GUI");
cv_frame.setSize(600, 400);
cv_frame.setLayout(new FlowLayout());
cv_content = new content();
cv_content.setBackground(Color.Black);
cv_content.setPreferredSize(new Dimension(500, 300));
cv_frame.add(cv_content);
gv_x = 0;
gv_y = 0;
cv_content.update();
}
}
public static class content extends JPanel {
public void paint(Graphics graphic) {
super.paint(graphic);
draw(graphic);
}
public void update() {
super.repaint();
}
public void draw(Graphics graphic) {
Graphics2D graphic2D = (Graphics2D) graphic;
graphic2D.setPaint(Color.Red);
graphic2D.fillRect(gv_x, gv_y, 100, 100);
}
}
}
I don't know why the call to the update function isn't doing
anything though.
It draws the square at 50x and 50y, the sets it to 0x and 0y
immediately and then when I call repaint I expected it to
be moved to it's new coordinates although it's still at
50x and 50y.
Why is this?

Your solution is to use KeyBindings.
https://docs.oracle.com/javase/tutorial/uiswing/misc/keybinding.html
and also.
You need to create a Swing Timer, Thread, or Loop , that manages the frames to be painted. and such
Here is a link for Swing Timers as they are pretty easy to implement:
https://docs.oracle.com/javase/tutorial/uiswing/misc/timer.html
A lot of programs I see also have this ( AKA. working with threads.):
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});

Grapghic doesn't move

I'm trying to make a code that will move a red ball with JButtons (and later add keybinders). There are no problems when I compile and when I run I see the ball but the JButtons won't affect him. I think the problem might be that the ball is drawed only once and then is called again and again without being drawed in the new position but I don't know how to fix that.
1) does anybody know how I can fix that?
2) is there a way to change the shape of a JPanel to a ball? (that would probably be a simpler way to move him)
package il.co.atlantis;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.*;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class KeyBinders implements ActionListener {
boolean right=true, left=false, up=false, down=false, inGame=true;
JPanel backgroundPanel, bannerPanel, scorePanel, applePanel;
JLabel currentScoreLabel, highestScoreLabel;
JButton upButton, downButton, rightButton, leftButton;
long millis =System.currentTimeMillis(), millisn =System.currentTimeMillis();
public static final int WID = 10, HEI = 10;
public static int x1 = 100, y1 = 100;
public class MyGraphics extends JComponent {
private static final long serialVersionUID = 1L;
MyGraphics() {
setPreferredSize(new Dimension(700, 500));
}
public void moveRight(){
++x1;
}
public void moveLeft(){
--x1;
}
public void moveUp(){
--y1;
}
public void moveDown(){
++y1;
}
public void paintComponent(Graphics g){
super.paintComponents(g);
g.setColor(Color.red);
g.fillOval(x1, y1, WID, HEI);
}
}
public JPanel CreateContentPane (){
JPanel totalGUI = new JPanel();
totalGUI.setLayout(null);
backgroundPanel = new JPanel();
backgroundPanel.setBackground(Color.black);
backgroundPanel.setLocation(100, 10);
backgroundPanel.setSize(700, 500);
totalGUI.add(backgroundPanel);
upButton = new JButton("up");
upButton.setLocation(0,0);
upButton.setSize(50,50);
totalGUI.add(upButton);
downButton = new JButton ("down");
downButton.setLocation(0,50);
downButton.setSize(50,50);
totalGUI.add(downButton);
rightButton = new JButton("right");
rightButton.setLocation(0,100);
rightButton.setSize(50,50);
totalGUI.add(rightButton);
leftButton = new JButton("left");
leftButton.setLocation(0,150);
leftButton.setSize(50,50);
totalGUI.add(leftButton);
MyGraphics tr = new MyGraphics();
tr.setLocation(100, 100);
backgroundPanel.add(tr);
return totalGUI;
}
public void ActionPerformed(ActionEvent h){
if(h.getSource() == upButton) {
--y1;
}
else if(h.getSource() == downButton){
++y1;
}
else if(h.getSource() == leftButton){
--x1;
}
else if(h.getSource() == rightButton){
++x1;
}
}
private static void createAndShowGUI() {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("[=] JButton Scores! [=]");
//Create and set up the content pane.
KeyBinders demo = new KeyBinders();
frame.setContentPane(demo.CreateContentPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(280, 190);
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
public KeyBinders() {
// TODO Auto-generated constructor stub
}
#Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
}

When you invoke action event, actionPerformed() function gets called, as you did. You have change the drawing position too. you need to call Component.repaint() which tells Swing t hat the entire component, whichever one you specified to be repainted , must be updated . So add this function calling in your code. For example:
public void ActionPerformed(ActionEvent h){
if(h.getSource() == upButton) {
--y1;
}
else if(h.getSource() == downButton){
++y1;
}
else if(h.getSource() == leftButton){
--x1;
}
else if(h.getSource() == rightButton){
++x1;
}
repaint();
}
Check the tutorial: Performing Custom Painting.

There's a method called repaint() you should familiarize yourself with.
When called on a component (such as a JFrame) it'll repaint all the components within. Naturally you need to call it if you want your changes to become visible on the screen.
As for custom painting, you shouldn't use a Component at all, rather use the Graphics.fillRect/fillOval etc. methods to just draw what you want.
See here for the custom painting tutorial.

Java function that gets called every frame

I was wondering if there was a function like void draw() which Processing programming language uses that gets called every frame. Or even just a function that loops infinitely when it gets called but only runs through it every time there is a new frame. I heard of something called a runnable in java how do i go about using this? also is there a better way then having a runnable with a delay like a function that is hardcoded to run every frame. Oh and also what is the function call that will allow me to see how much time (in milliseconds preferably) since the application has started running that way i can make my runnables / frame calls much more precise so that the game runs about the same speed on every computer regardless of the frame rate.

Perhaps you need something like this
import java.awt.Graphics;
import java.awt.Point;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
public class Repainter extends JPanel {
private Point topLeft;
private int increamentX = 5;
public Repainter() {
topLeft = new Point(100, 100);
}
public void move() {
topLeft.x += increamentX;
if (topLeft.x >= 200 || topLeft.x <= 100) {
increamentX = -increamentX;
}
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(topLeft.x, topLeft.y, 100, 100);
}
public void startAnimation() {
SwingWorker<Object, Object> sw = new SwingWorker<Object, Object>() {
#Override
protected Object doInBackground() throws Exception {
while (true) {
move();
Thread.sleep(100);
}
}
};
sw.execute();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Repaint Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
Repainter repainter = new Repainter();
frame.add(repainter);
repainter.startAnimation();
frame.setVisible(true);
}
});
}
}