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PaintComponent don't seem to get call or to show

My problem is really simple : I have this little program, and it just don't show the red box I'm trying to make :
Main
public class Main {
public static void main(String[] args) {
Affichage a = new Affichage();
a.setVisible(true);
}
}
Affichage :
import java.awt.*;
import javax.swing.*;
public class Affichage extends Frame{
public Affichage(){
setTitle("Exo 1 : Galerie");
setSize(1120,560);
Graphique graph = new Graphique();
this.add(graph);
}
}
Graphique :
import javax.swing.*;
import java.awt.*;
public class Graphique extends JComponent {
#Override
public void paintComponents(Graphics g) {
super.paintComponents(g);
Graphics pinceau = g.create();
pinceau.setColor(Color.RED);
pinceau.fillRect(100, 100, 200, 200);
System.out.println("test");
}
}
I bet it's ridicule but I can't find what it is, help me.
PS : yes the test don't get print too

Actually, don't extend JFrame as it is bad practice. Just make an instance of it. To paint, extend JPanel and override paintComponent.
JFrame f = new JFrame();
f.add(new MyPanel());
class MyPanel extends JPanel {
// other stuff
public void paintComponent(Graphics g) {
super.paintComponent(g);
// painting stuff.
}
}
And remember not to mix Swing and AWT components.

You are adding a Swing component (javax.swing.JComponent) to an AWT frame (java.awt.Frame). Noone will call the paintComponents() method, that's why you don't get any output or result. Extend from javax.swing.JFrame instead, so you have a Swing frame with a Swing component.

JFrame (Swing) update(graphics) error

I have a little game with little Rect, which are moving and I need to update the Graphics by doing this.update(MyGraphics) in my onUpdate method, which gets called every 50 millisekonds. But when I do this this.update(MyGraphics) all my buttons and textfields are glitched.
Does somebody have an idea how to fix it?

when I do this this.update(MyGraphics) all my buttons and textfields are glitched.
Don't invoke update(...) directly. That is not the way custom painting is done.
Instead when you do custom painting you override the paintComponent(...) method of the JPanel:
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
// add your custom painting here
}
I have a little game with little Rect, which are moving
If you want animation then you should use a Swing Timer to schedule the animation. Then when the Timer fires you invoke a method on your custom class to change the location of the rectangle and then you invoke repaint(). This will cause the panel to be repainted.
Read the Swing Tutorial. There are sections on:
Performing Custom Painting
How to Use Swing Timers
to get your started with basic examples.

Here is one of the examples how to update JPanel by a timer.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class MainClass extends JPanel {
static JFrame frame = new JFrame("Oval Sample");
static MainClass panel = new MainClass(Color.CYAN);
static Color colors[] = {Color.RED, Color.BLUE, Color.GREEN, Color.YELLOW};
static Color color;
static int step = 0;
public MainClass(Color color) {
this.color = color;
}
final static Timer tiempo = new Timer(500, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// paintComponent();
System.out.println("Step: " + step++);
if (step % 2 == 0) {
color = Color.DARK_GRAY;
} else {
color = Color.BLUE;
}
panel.repaint();
}
});
#Override
public void paintComponent(Graphics g) {
int width = getWidth();
int height = getHeight();
g.setColor(color);
g.drawOval(0, 0, width, height);
}
public static void main(String args[]) {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(2, 2));
panel = new MainClass(colors[2]);
frame.add(panel);
frame.setSize(300, 200);
frame.setVisible(true);
tiempo.start();
}
}

Can't see child JPanel in JPanel in JFrame

I've created a JFrame.
Inside this JFrame, I've created a JPanel.
Inside this JPanel I've created another JPanel (lets call it "A").
I've drawn in "A" a rectangle, and wanted to create buttons using graphics.
There is no rectangle in my gui. I could see that the paintComponent() method inside "A" is not being invoked.
Code:
The JPanels: (the child JPanel is inner class)
public class MemoryPanel extends JPanel {
public MemoryPanel(){
setPreferredSize(new Dimension(350,448));
}
#Override
public void paintComponent(Graphics g) {
//POSITIONING
setLayout(new BorderLayout());
//CREATE MEMORY BUTTONS
MemButton a=new MemButton();
//Drawing Rectangles for Memory
add(a,BorderLayout.CENTER);
}
private class MemoryButton extends JPanel{
public MemoryButton(){
setLayout(null);
setPreferredSize(new Dimension(87,40));
}
#Override
public void paintComponent(Graphics g){
Graphics2D td= (Graphics2D)g;
td.drawRect(0, 0, 20, 20);
}
}
}

You should program the JButtons first in order for your graphics to work as buttons. I belive this post will help you with that:
Creating a custom button in Java
I you want a rectangle to be the background for your buttons you can draw it in your main panel and add the buttons on it. Try using different Layouts to mantain some order.

I've made a simple GUI to test your code and the rectangle appears correctly.
I made no relevant changes in the code that you posted.
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class SimpleJFrameProgram extends JFrame {
private static final long serialVersionUID = 1L;
public SimpleJFrameProgram() {
super("TEST");
initComponents();
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
}
private void initComponents() {
MemoryPanel memoryPanel = new MemoryPanel();
this.add(memoryPanel);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
new SimpleJFrameProgram();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
I've applyed minor changes to your MemoryPanel: replaced MemButton by your MemoryButton and fill the rectangle in red to improve its visibility for the test. Without this last change, the rectangle appears too.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;
public class MemoryPanel extends JPanel {
public MemoryPanel(){
setPreferredSize(new Dimension(350,448));
}
#Override
public void paintComponent(Graphics g) {
// POSITIONING
setLayout(new BorderLayout());
// CREATE MEMORY BUTTONS
MemoryButton a = new MemoryButton();
// Drawing Rectangles for Memory
add(a,BorderLayout.CENTER);
}
private class MemoryButton extends JPanel{
public MemoryButton(){
setLayout(null);
setPreferredSize(new Dimension(87,40));
}
#Override
public void paintComponent(Graphics g) {
Graphics2D td = (Graphics2D) g;
td.setColor(Color.red);
td.fillRect(0, 0, 20, 20);
}
}
}
This is the obtained result:
Maybe your problem is located on initializing the parent JFrame.

Changing the class name of MemoryButton fixed it.
I had another package with the same class name.

Java: Using graphics component within an ActionListener

I have two separate class and driver files, and in the class file I create the paint method:
public void paint(Graphics g){
g.drawLine(......
....
//along with all of my other draw commands
}
Further down in the code, I create a JButton and within this button's action listener I don't know how to use a Graphics object to create more graphics in the JFrame. Should I be adding something to my driver to make this happen, or is there a way to use these graphics within my action listener? Thank you, and any help is appreciated.

You need to draw everything within the paint method. The actionPerformed should only change the state of something already in the paint method, and then call repaint. For example
boolean drawHello = true;
boolean drawWorld = false;
protected void paintComponent(Graphics g) {
super.paintCompoent(g);
if (drawHello)
g.drawString("Hello", 50, 50);
if (drawWorld)
g.drawString("World", 10, 10);
}
Then in your actionPerformed, you can change the state of drawWorld to true and call repaint().
public void actionPerformed(ActionEvent e) {
drawWorld = true;
repaint();
}
So as you can see, everything should be drawn in the paintComponent method. You can just hide and paint renderings, and make them "visible" from a action command. You should already have predefined what could posibly be drawn. Then just change the state of it rendering
And as #MadPrgrammer pointed out, you should not be painting on top-level containers like JFrame. Instead paint on a custom JPanel or JComponent and override the paintComponent method, instead of JFrame and paint
Here's an example where I draw a new square every time the button is pressed. If look at the code, you will see that in the paintComponent method, I loop through a list of Squares and draw them, and in the actionPerformed all I do is add a new Square to the List and call repaint()
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class AddSquares {
private int R = 0;
private int G = 0;
private int B = 0;
private int xLoc = 0;
private int yLoc = 0;
List<Square> squares = new ArrayList<>();
private JButton addSquare = new JButton("Add Square");
private RectsPanel panel = new RectsPanel();
public AddSquares() {
addSquare.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
Color color = new Color(R, G, B);
squares.add(new Square(xLoc, yLoc, color));
panel.repaint();
R += 10;
G += 20;
B += 30;
xLoc += 20;
yLoc += 20;
}
});
JFrame frame = new JFrame("Draw Squares");
frame.add(panel, BorderLayout.CENTER);
frame.add(addSquare, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
private class RectsPanel extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Square square : squares) {
square.drawSquare(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(250, 250);
}
}
private class Square {
int x = 0;
int y = 0;
Color color;
public Square(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public void drawSquare(Graphics g) {
g.setColor(color);
g.fillRect(x, y, 75 ,75);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
AddSquares addSquares = new AddSquares();
}
});
}
}

It's difficult to be 100%, but it would seem as you don't understand how custom painting is performed in Swing.
Start by taking a look at Performing Custom Painting and Painting in AWT and Swing.
Essentially, painting is arranged by the Repaint Manager, which decides what and when something should be painted. It then calls (through a chain of methods) the paint method of the components it thinks need to be updated, passing it a reference to a Graphics context that should be used to actually paint on.
Basically, when ever your paint method is called, you should create paint the current state of your painting.
You should avoid overriding paint and instead use paintComponent from classes the extend JComponent

Your question is a little on the vague side as to what you are actually wondering about but generally speaking:
We don't override paint in Swing, we override paintComponent.
If you are already aware of this, you may be overriding paint because you are doing it on a JFrame and you found that JFrame does not have a paintComponent method. You shouldn't override paint on a JFrame. Instead, create a JPanel or something to put inside the frame and override paintComponent on the panel.
Question about the ActionListener.
It sounds like you are wanting to do painting outside of paintComponent in which case probably the best way is to do painting to a separate Image. Then you paint the Image on to the panel in paintComponent. You can also put an Image in a JLabel as an ImageIcon. Here is a very simple drawing program using MouseListener that demonstrates this (taken from here):
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
class PaintAnyTime {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new PaintAnyTime();
}
});
}
final BufferedImage image = (
new BufferedImage(500, 500, BufferedImage.TYPE_INT_ARGB)
);
final JFrame frame = new JFrame();
final JLabel label = new JLabel(new ImageIcon(image));
final MouseAdapter drawer = new MouseAdapter() {
Graphics2D g2D;
#Override
public void mousePressed(MouseEvent me) {
g2D = image.createGraphics();
g2D.setColor(Color.BLACK);
}
#Override
public void mouseDragged(MouseEvent me) {
g2D.fillRect(me.getX(), me.getY(), 3, 3);
label.repaint();
}
#Override
public void mouseReleased(MouseEvent me) {
g2D.dispose();
g2D = null;
}
};
PaintAnyTime() {
label.setPreferredSize(
new Dimension(image.getWidth(), image.getHeight())
);
label.addMouseListener(drawer);
label.addMouseMotionListener(drawer);
frame.add(label);
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
#MadProgrammer has already linked to the articles that I was going to link to.

Making an image show up in Java

I've been struggling to get an image to show up for some time now. Ive read a few different things, and all of them seem to have different ways of showing images. Can someone tell me what I'm doing wrong? I'm trying to make a program that uses 2 classes to make a picture show up in a frame. I guess what I don't understand still is what a Graphics object is, what a Graphics2D object is and how its different, and what method from what class do I call in order to make an image show up. Here is my code:
public class Smiley {
private BufferedImage smileyFace;
private Graphics2D renderWindow;
private Dimension smileyPosition;
private File smileyFile;
public Smiley() {
try{
smileyFile = new File("C:\\Users\\MyName\\Desktop\\smiley.png");
smileyFace = ImageIO.read(smileyFile);
}
catch (Exception e){
System.out.println("There was an error finding or reading the file \" smiley.png.\"");
}
MainScreen.graphicPane.drawImage(smileyFace,50,50, null);
}
and the second class:
public class MainScreen extends JFrame{
public static MainScreen ms;
public static Graphics2D graphicPane;
public static void main (String[] args){
MainScreen ms = new MainScreen();
Smiley newSmiley = new Smiley();
}
public MainScreen(){
super("Main Screen Window");
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setVisible(true);
this.setSize(500,800);
this.getContentPane().setBackground(Color.black);
graphicPane = (Graphics2D) this.getContentPane().getGraphics();
}
}
the program compiles with no errors and nothing is reported back to me about not finding the file.

Your going to need some sore of paint method. For that you will require a Component to paint on. You need to learn a GUI framework, like Swing. There are clear compoents you can paint on like a JPanel. With that panel you need to override its paintComponent method.
The Graphcics object is what the component uses to actually paint the graphic onto the component.
The Graphics2D object just extends the capabilities of the Graphics object.
You should take a look at the Swing tuorial and the **Graphics toturial
To get your program running though you would do something like this
public class DrawPanel extends JPanel {
BufferedImage smileyFace;
public DrawPanel() {
try{
smileyFile = new File("C:\\Users\\MyName\\Desktop\\smiley.png");
smileyFace = ImageIO.read(smileyFile);
}
catch (Exception e){
System.out.println("There was an error finding or reading the file \" smiley.png.\"");
}
}
#Override
protected void paintComponent(Graphics g){
super.paintComponent(g);
g.drawImage(smileyFace,50,50, this);
}
#Override
public Dimension getPreferredSize(){
return new Dimension(500, 500);
}
}
Then you can instantiate that panel in another class, adding it to a JFrame to run it
public class Main {
public static void main(String[] args) {
SwingUtiliites.invokeLater(new Runnable(){
public void run() {
JFrame frame = new JFrame();
frame.add(new DrawPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
});
}
}

You are calling this in your constructor for your Smiley class.
MainScreen.graphicPane.drawImage(smileyFace,50,50, null);
If you are going to paint the image yourself you need to override paintComponent() in a component that gets added to your main screen.
Or just add the image to a JLabel that you added to the main screen.

You draw image in wrong way.
For using drawImage() you need to use that in paintComponent() method of JComponent(for example JPanel), examine next code:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.beans.Transient;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Example extends JFrame {
public Example() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Smiley());
frame.pack();
frame.setVisible(true);
}
public static void main(String args[]) {
new Example();
}
class Smiley extends JPanel{
private BufferedImage smileyFace;
Smiley(){
try {
File smileyFile = new File("C:\\Users\\MyName\\Desktop\\smiley.png");
smileyFace = ImageIO.read(smileyFile);
} catch (Exception e) {
System.out
.println("There was an error finding or reading the file \" smiley.png.\"");
}
}
#Override
#Transient
public Dimension getPreferredSize() {
return new Dimension(smileyFace.getWidth(),smileyFace.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(smileyFace, 0,0, this);
}
}
}
or you can add your image to JLabel and that do all for you, change Smile class like next:
class Smiley extends JPanel{
Smiley(){
ImageIcon icon = new ImageIcon("C:\\Users\\MyName\\Desktop\\smiley.png");
JLabel l = new JLabel(icon);
add(l);
}
}
ALso read more about customPaintings.