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Java Swing moving shapes with mouse

I am working on a simple object drawing program using Swing in Java.
My program simply should draw shapes according to buttons when clicked, and move any shapes with the mouse. I have four buttons which draw rectangle, circle and square on screen. So far I did managed to draw to shapes when you click on buttons. but i want to move the shapes on screen which it did not work out.
The problem is this: When I click on circle shape to drag it around with mouse, it clears all the screen and noting is on the screen.
And, is there a way to clean all the screen when I click on clear button?
Thank you?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class PaintProject extends JComponent implements ActionListener,
MouseMotionListener {
private int CircleX=0;
private int CircleY=0;
private int RectX=100;
private int RectY=100;
private int SquareX=300;
private int SquareY=200;
public static void main(String[] args) {
JFrame frame = new JFrame("NEW PAINT PROGRAME!");
JButton CircleButton = new JButton("Circle");
CircleButton.setActionCommand("Circle");
JButton RectangleButton = new JButton("Rectangle");
RectangleButton.setActionCommand("Rectangle");
JButton SquareButton = new JButton("Square");
SquareButton.setActionCommand("Square");
PaintProject paint = new PaintProject();
CircleButton.addActionListener(paint);
RectangleButton.addActionListener(paint);
SquareButton.addActionListener(paint);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
frame.add(paint);
frame.add(CircleButton);
frame.add(RectangleButton);
frame.add(SquareButton);
frame.addMouseMotionListener(paint);
frame.pack();
frame.setVisible(true);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
private void drawCircle() {
Graphics g = this.getGraphics();
g.setColor(Color.red);
g.fillOval(CircleX, CircleY, 100, 100);
}
private void drawRectangle() {
Graphics g = this.getGraphics();
g.setColor(Color.green);
g.fillRect(RectX, RectY, 100, 300);
}
private void drawSquare() {
Graphics g = this.getGraphics();
g.setColor(Color.blue);
g.fillRect(SquareX, SquareY, 100, 100);
}
#Override
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if (command.equals("Circle")) {
drawCircle();
}
else if (command.equals("Rectangle")) {
drawRectangle();
}
else if (command.equals("Square")) {
drawSquare();
}
}
#Override
public void mouseDragged(MouseEvent e) {
CircleX=e.getX();
CircleY=e.getY();
repaint();
}
}

As noted here and here, getGraphics() is not how to perform custom painting in Swing. Instead, override paintComponent() to render the desired content. It looks like you want to drag shapes using the mouse. A basic approach to moving a selected object is shown here; substitute your fillXxx() invocation for the drawString() shown there. For multiple shapes, use a List<Shape>; the clear command then becomes simply List::clear. A complete example is cited here; it features moveable, selectable, resizable, colored nodes connected by edges.

Drawing multiple Shapes on the same Canvas when pressed a button

I need to draw a square,line,circle when pressed the corespondent button. Also I need to do this using FactoryMethod design pattern.
I simply don't get how to draw on the same canvas, and because I have a class for every shape, how do i get the corresponding paint(Graphics g) method?
This is what I have so far:
public interface Shape
{
public void draw();
}
Square class
public class Square extends Canvas implements Shape
{
Graphics g;
Canvas c;
public Canvas getCanvas()
{
return c;
}
public void setCanvas(Canvas c)
{
this.c=c;
}
#Override
public void draw()
{
g.drawRect(20, 30,100,100);
}
public void paint(Graphics g)
{
g.drawRect(20, 30,100,100);
g.setColor(Color.BLUE);
}
}
Factory
public class ClassFactory extends Canvas{
JButton patrat;
Figura d;
String nameButon;
Graphics g;
Canvas c;
public Canvas getCanvas()
{
return c;
}
public void setCanvas(Canvas c)
{
this.c=c;
}
public ClassFactory()
{
super();
this.setBounds(0,0,500,450);
this.setBackground(Color.CYAN);
JButton square=new JButton("square");
patrat.setBounds(510, 10, 80,25);
JPanel panel=new JPanel();
panel.setLayout(null);
panel.setBounds(0,0,600,500);
panel.setBackground(Color.GRAY);
panel.add(this);
this.addComponentListener(p);
panel.add(square);
JFrame f=new JFrame("Draw");
f.setLayout(null);
f.setBounds(50,50,700,600);
f.getContentPane().setBackground(Color.DARK_GRAY);
f.setResizable(false);
f.add(panel);
f.show();
}
public Shape getFigure()
{
Shape d=null;
if(nameButton.equals("square"))
{
d=new Square();
}
return d;
}
}

Suggestions:
The factory should not create a GUI, should not extend Canvas, or really extend anything, it should not create a JFrame or do anything of the sort. It should concern itself only with creating objects of Shape child classes. The GUI creation code should be elsewhere.
Likely the factory's getFigure(...) method will be the one to produce this. It should likely accept a parameter, perhaps a String or an enum, that tells it what sub-class of Shape to produce.
Shape's draw method should likely accept a Graphics parameter so that its children can use it to draw with.
You shouldn't mix AWT components (i.e., Canvas) and Swing components together unnecessarily. Instead, just draw in a JPanel's paintComponent(Graphics g) method, not in a Canvas's paint(Graphics g) method.
In that JPanel have a Shape variable that is not initialized, perhaps called shape.
Inside of paintComponent(...) check if shape is null. If not, draw it by calling shape.draw(g).
In your JButton ActionListeners, have the Factory create a Shape child class object and assign it to the shape variable
Then call repaint() on the JPanel that does the drawing.

Why won't the JPanels display?

I'm learning some swing and awt programming in Java so I decided to make Pong. The Main class is the parent JFrame. It instantiates a Ball and a Paddle and adds them (they are JPanels). However, only the last one added is displayed. How do I fix this?
Code:
public class Main extends JFrame {
public Main() {
super("Pong");
add(new Ball());
add(new Paddle());
setSize(500, 500);
setBackground(Color.orange);
setLocationRelativeTo(null);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new Main().setVisible(true);
}
}
The Ball class:
public class Ball extends JPanel implements ActionListener {
Timer timer;
private Vec2d position;
private Vec2d velocity;
private Dimension ballSize;
public Ball() {
super();
position = new Vec2d(50, 50);
velocity = new Vec2d(2, 3);
timer = new Timer(25, this);
ballSize = new Dimension(40, 40);
timer.start();
}
#Override
public void actionPerformed(ActionEvent ae) {
//Perform game frame logic
bounceBall();
repaint();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillArc((int)position.x, (int)position.y, ballSize.width,
ballSize.height, 0, 360);
position.add(velocity);
}
private void bounceBall() {
if(position.x < 0 || position.x > getWidth() - ballSize.width) {
velocity.x *= -1;
}
if (position.y < 0|| position.y > getHeight() - ballSize.height) {
velocity.y *= -1;
}
}
}
And finally, the Paddle class:
public class Paddle extends JPanel implements ActionListener {
private Vec2d position;
private double yVelocity;
private Rectangle rect;
private Timer timer;
public Paddle() {
super();
position = new Vec2d(30, 250);
yVelocity = 0;
timer = new Timer(25, this);
timer.start();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillRect((int) position.x, (int) position.y, 20, 40);
}
#Override
public void actionPerformed(ActionEvent ae) {
repaint();
}
}
Note that Vec2d is simply a small two dimensional Vector class I threw together. Also, the Pong logic (collision between Paddle and ball, scoring, etc) is not implemented. I just want to get it to draw correctly
Thanks in advance for the help!

The first thing to do is to add the JPanels to the content pane of your window, not to the window itself. I'm surprised you didn't get a runtime warning about that.
Also, it looks like you are planning to have each of your panels fill the screen, but paint only a small section of it. If that is really the way you want to do it, then you need to do setOpaque(false) on them so the panels under them can show through. But probably a better solution would be to have a single JPanel that is the drawing surface, and have its paintComponent() pass off the Graphics to each of the game objects to let them draw themselves.

add(new Ball());
add(new Paddle());
By default, the layout manager of a JFrame is a BorderLayout. And if you don't specify where you want to add a component (BorderLayout.WEST, or EAST, etc.), the it's added at the center. So you add two components at the same place: in the center. So, only one of them is displayed.

You are adding the Ball and Paddle to the same BorderLayout.CENTER position so only the last one added, (i.e. the Paddle) is displayed. You could use a GridLayout here to display:
setLayout(new GridLayout(1, 2));
add(new Paddle());
add(new Ball());

in the Paddle class, you never add the velocity to position with position.add(velocity) like you do in your ball class..

JPanel setBackground(Color.BLACK) does nothing

I have the folowing custom JPanel and I have aded it to my frame using Netbeans GUI builder but the background won't change! I can see the circle, drawing with g.fillOval(). What's wrong?
public class Board extends JPanel{
private Player player;
public Board(){
setOpaque(false);
setBackground(Color.BLACK);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.red);
g.fillOval(player.getxCenter(), player.getyCenter(), player.getRadius(), player.getRadius());
}
public void updatePlayer(Player player){
this.player=player;
}
}

If your panel is 'not opaque' (transparent) you wont see your background color.

You have to call the super.paintComponent(); as well, to allow the Java API draw the original background. The super refers to the original JPanel code.
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.red);
g.fillOval(player.getxCenter(), player.getyCenter(), player.getRadius(), player.getRadius());
}

You need to create a new Jpanel object in the Board constructor.
for example
public Board(){
JPanel pane = new JPanel();
pane.setBackground(Color.ORANGE);// sets the background to orange
}

setOpaque(false);
CHANGED to
setOpaque(true);

I just tried a bare-bones implementation and it just works:
public class Test {
public static void main(String[] args) {
JFrame frame = new JFrame("Hello");
frame.setPreferredSize(new Dimension(200, 200));
frame.add(new Board());
frame.pack();
frame.setVisible(true);
}
}
public class Board extends JPanel {
private Player player = new Player();
public Board(){
setBackground(Color.BLACK);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.red);
g.fillOval(player.getCenter().x, player.getCenter().y,
player.getRadius(), player.getRadius());
}
}
public class Player {
private Point center = new Point(50, 50);
public Point getCenter() {
return center;
}
private int radius = 10;
public int getRadius() {
return radius;
}
}

In order to completely set the background to a given color :
1) set first the background color
2) call method "Clear(0,0,this.getWidth(),this.getHeight())" (width and height of the component paint area)
I think it is the basic procedure to set the background...
I've had the same problem.
Another usefull hint : if you want to draw BUT NOT in a specific zone (something like a mask or a "hole"), call the setClip() method of the graphics with the "hole" shape (any shape) and then call the Clear() method (background should previously be set to the "hole" color).
You can make more complicated clip zones by calling method clip() (any times you want) AFTER calling method setClip() to have intersections of clipping shapes.
I didn't find any method for unions or inversions of clip zones, only intersections, too bad...
Hope it helps

Problem with calling repaint() and paintComponent() method, using mvc design pattern

I'm creating a small game, you click buttons (up, down, left and right) to control a cat (represented by a rectangle) to chase a mouse (represented by another rectangle). Lame I know... anyway I'm using the mvc design pattern and I am having problems calling the repaint method from button listeners in the controller on the panel where the two rectangles are to be 'painted'. They paint successfully the first time but not any further time.
I've implemented the the paintComponent() method in two ways but both didn't work
Create a separate class that extends JPanel and does the paintComponent business, creating a new object of that class in the view and using it to paint the rectangles.
Creating a JPanel and writing the paintComponent stuff in the parenthesis of the new JPanel object.
and I've implemented the code to in the controller to repaint in two ways and both didn't work
Call a method from the view that returns the jpanel that uses the paintComponent method and calling repaint on it.
Creating a jpanel in the controller and assigning the panel from the view to it then calling repaint on that.
The code for the view and controller (which is long, sorry!) is below, it also includes the commented out stuff I couldn't get to work from the two methods to approaching the problem mentioned before...
View
/*
* gameView.java
*/
package game;
import java.awt.;
import java.awt.event.;
import javax.swing.*;
public class gameView extends JFrame{
//components
private JButton up = new JButton("Up");
private JButton down = new JButton("Down");
private JButton left = new JButton("Left");
private JButton right = new JButton("Right");
//panels
private JPanel content = new JPanel();
//boardPanel leftPanel = new boardPanel();
private Stroke drawingStroke = new BasicStroke(1);
private JPanel leftPanel = new JPanel(){
#Override
protected void paintComponent(Graphics g) {
super.paintComponents(g);
myPaint(g);
}
};
private JPanel rightPanel = new JPanel();
//model
private gameModel model;
//mouse and cat
private Rectangle cat;
private Rectangle mouse;
public void myPaint(Graphics g){
Graphics2D g1 = (Graphics2D)g;
Graphics2D g2 = (Graphics2D)g;
g1.setStroke(drawingStroke);
g1.draw(cat);
g1.setPaint(Color.yellow);
g1.fill(cat);
g2.setStroke(drawingStroke);
g2.draw(mouse);
g2.setPaint(Color.red);
g2.fill(mouse);
}
//constructor
public gameView(gameModel _model){
model = _model;
//cat and mouse
cat = new Rectangle(_model.getCatX(), _model.getCatY(), 10, 10);
mouse = new Rectangle(_model.getMouseX(), _model.getMouseY(), 10, 10);
//layout
content.setSize(500, 400);
content.setLayout(new GridLayout(0,2));
leftPanel.setSize(200, 200);
leftPanel.setBackground(Color.blue);
rightPanel.setSize(100, 400);
rightPanel.setLayout(new FlowLayout());
rightPanel.add(new JLabel("Controls"));
rightPanel.add(up);
rightPanel.add(down);
rightPanel.add(left);
rightPanel.add(right);
content.add(leftPanel);
content.add(rightPanel);
this.setSize(500, 400);
this.setContentPane(content);
this.setTitle("Cat & Mouse Game");
}
//returns the leftPanel to repaint in the controller
public JPanel getLeft(){
return leftPanel;
}
//listeners for buttons
public void addUpListener(ActionListener moveUp){
up.addActionListener(moveUp);
}
public void addDownListener(ActionListener moveDown){
down.addActionListener(moveDown);
}
public void addLeftListener(ActionListener moveLeft){
left.addActionListener(moveLeft);
}
public void addRightListener(ActionListener moveRight){
right.addActionListener(moveRight);
}
public void addCloseListener(WindowListener close){
this.addWindowListener(close);
}
//
public Rectangle getCat(){
return cat;
}
public Rectangle getMouse(){
return mouse;
}
//left side board panel
/*class boardPanel extends JPanel{
Stroke drawingStroke = new BasicStroke(1);
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g1 = (Graphics2D)g;
g1.setStroke(drawingStroke);
g1.draw(cat);
g1.setPaint(Color.yellow);
g1.fill(cat);
Graphics2D g2 = (Graphics2D)g;
g2.setStroke(drawingStroke);
g2.draw(mouse);
g2.setPaint(Color.red);
g2.fill(mouse);
}
}
public JPanel getLeft(){
return leftPanel;
}*/
}
Controller
/*
* gameController.java
*/
package game;
import java.awt.event.;
import javax.swing.;
public class gameController {
private gameModel model;
private gameView view;
private JPanel lp = new JPanel();
public gameController(gameModel _model, gameView _view){
model = _model;
view = _view;
lp=_view.getLeft();
//listeners
view.addUpListener(new UpListener());
view.addDownListener(new DownListener());
view.addLeftListener(new LeftListener());
view.addRightListener(new RightListener());
view.addCloseListener(
new WindowAdapter(){
public void windowClosing(WindowEvent we){
System.exit(0);
}
});
}
//DOWN
class DownListener implements ActionListener{
public void actionPerformed(ActionEvent e){
model.setCatY((model.getCatY()+10));
//do a random move for the mouse
//model.randomMove();
//view.getLeft().repaint();
lp.repaint();
System.out.println("x="+model.getCatX()+"y="+model.getCatY());
}
}
//LEFT
class LeftListener implements ActionListener{
public void actionPerformed(ActionEvent e){
model.setCatY((model.getCatY()-10));
//do a random move for the mouse
//model.randomMove();
//view.getLeft().repaint();
lp.repaint();
System.out.println("x="+model.getCatX()+"y="+model.getCatY());
}
}
//RIGHT
class RightListener implements ActionListener{
public void actionPerformed(ActionEvent e){
model.setCatY((model.getCatY()+10));
//do a random move for the mouse
//model.randomMove();
//view.getLeft().repaint();
lp.repaint();
System.out.println("x="+model.getCatX()+"y="+model.getCatY());
}
}
}

Looks like your button listeners update the model, but nothing actually updates the coordinates of the cat and mouse rectangles. They get their initial bounds from the model, but then are never updated.
The view should probably listen to the model to sync the cat and mouse's locations to the actual Rectangle objects.