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How can I use 2 Class paint in JFrames generate code by Palette in Netbeans?

public class DrawST extends javax.swing.JFrame {
/**
* Creates new form DrawST
*/
public DrawST() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
#SuppressWarnings("unchecked")
Generated code
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new DrawST().setVisible(true);
}
});
}
class Class01 extends JPanel{
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
}
}
class Class02 extends JPanel{
#Override
public void paintComponent(Graphics g){
super.paintComponent(g);
}
}
// Variables declaration - do not modify
// End of variables declaration
}
How can I use both Class01 and Class02 to paint in this JFrame, Class01 will draw pipes, and Class02 will draw frog(Happy Frog). I try to create Container contain = getContentPane(); and add two classes. But it work only 1 class added.If I add two classes, the JFrame won't draw anything.

You're making a common mistake: creating drawing classes that extend Swing components when they should be logical classes, not component classes:
If you're doing animation, usually only one component, often a JPanel does the drawing, meaning the paintComponent method is overridden in one component.
If you desire a class to draw a specific sprite, such as a frog, or pipes, then these sprites will be drawn in that same single drawing class described above.
Component classes, classes that extend Swing GUI components such as JPanels are usually placed into the GUI as components -- building blocks of the GUI that are placed in a limited location in the GUI, and that paint themselves and their children only.
So to do drawings where multiple sprites occupy the same drawing space, the classes that create these sprites should not extend JPanel or similar Swing components and instead should only be logical classes (classes that are not components), and then that are drawn by that single drawing JPanel.
For example
public class DrawST extends javax.swing.JFrame {
public DrawST() {
// add the DrawingPanel to the JFrame here
}
}
// this class extends JPanel and does *all* the drawing
public class DrawingPanel extends JPanel {
private Frog frog = new Frog(0, 0);
private List<Pipe> pipes = new ArrayList<>();
private Timer timer; // you'll probably need a Swing Timer to drive the animation
// a single paintComponent method is present
protected void paintComponent(Graphics g) {
super.paintComponent(g); // Don't forget this
frog.draw(g); // have this component draw a frog
for (Pipe pipe : pipes) {
pipe.draw(g); // draw all the pipes
}
}
}
// does not extend JPanel
public class Frog {
private int x;
private int y;
public Frog(int x, int y) {
this.x = x;
this.y = y;
}
public void draw(Graphics g) {
// use x, y, and g to draw a frog at x,y location
}
}
// does not extend JPanel (not sure what a pipe is, TBH)
public class Pipe {
private int x;
private int y;
// other? length, color, width?
public void draw(Graphics g) {
// use x, y, and g to draw a pipe.
// maybe also needs a length, color, width?
}
}

Using repaint() in different class instances in one panel

I have a draw class that extends JPanel and has a void method called drawing with repaint() in it.
public class draw extends JPanel {
public draw(int position_x, int position_y, int width, int height) {
positionx = position_x;
positiony = position_y;
this.width = width;
this.height = height;
}
public void drawing() {
repaint();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillRect(positionx, positiony, width, height);
}
}
So, my intention is create a lot of this rectangles in a JPanel so they create a graphic bar.
public class coin_launcher {
public static void main(String[] args) {
JFrame frame = new JFrame("Coin Launcher");
frame.setVisible(true);
frame.setSize(1920, 1080);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
draw object = new draw(2,2,100,2);
frame.add(object);
object.drawing();
draw object2 = new draw(2,6,200,2);
frame.add(object2);
object2.drawing();
}
}
The problem is that when I call drawing() in both of the objects only one gets drawn.
If use the debugger its only the first one, if I dont, its only the second one. I need to make 100 bars but it literally repaints the JPanel every time, how can I add different draw class in one JPanel without erasing the others?

JFrame uses a BorderLayout by default, this means that only the last component added (to the default centre position) will be managed by the layout.
See BorderLayout for more details.
An immediate solution might be to use a different layout manager, but I would argue that's the wrong solution.
Instead, you should have ONE component, which is capable of paint multiple bars, based on the data available from a "model"
This decouples the source of the data from the presentation of the data, allowing to produce multiple different implementations of these, which shouldn't break the other.
In this case, the "view" shouldn't care how the data is obtained or marinated, only that it conforms to a specified contract, like wise the data doesn't care how its presented.
See Model-View-Controller for more details

This answer is a very basic and simplified example of
"you should have ONE component, which is capable of paint multiple
bars, based on the data available from a "model"
quoted from MadProgrammer's answer.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Arrays;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class CoinLauncher {
public static void main(String[] args) {
JFrame frame = new JFrame("Coin Launcher");
frame.setSize(920, 480);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//data to be painted. for better implementation use a model class that
//encapsulates the data
Rectangle[] bars = {
new Rectangle(2,2,100,2),
new Rectangle(2,6,200,2),
};
Draw object = new Draw(Arrays.asList(bars));
frame.add(object);
frame.setVisible(true);
}
}
class Draw extends JPanel {
private final List<Rectangle> bars;
Draw(List<Rectangle> bars) {
this.bars = bars;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
for(Rectangle bar : bars){
g.fillRect(bar.x, bar.y, bar.width, bar.height);
}
}
}
Implementing a model to encapsulate data need for the view, can be as simple as :
public class CoinLauncher {
public static void main(String[] args) {
JFrame frame = new JFrame("Coin Launcher");
frame.setSize(920, 480);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Model model = new Model();
model.addBar( new Rectangle(2,2,100,2) );
model.addBar( new Rectangle(2,6,200,2) );
Draw object = new Draw(model);
frame.add(object);
frame.setVisible(true);
}
}
class Draw extends JPanel {
private final List<Rectangle> bars;
Draw(Model model) {
bars = model.getBars();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
for(Rectangle bar : bars){
g.fillRect(bar.x, bar.y, bar.width, bar.height);
}
}
}
class Model {
private final List<Rectangle> bars;
Model(){
bars = new ArrayList<>();
}
void addBar(Rectangle rectangle){
bars.add(rectangle);
}
List<Rectangle> getBars() { return bars; }
}

JApplet repaint() doesn't work

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.

Calling repaint from another class JFrame

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.

JPanel Repaint Not Clearing

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.