Drawing a dynamic graph. - java

By saying dynamic graph i mean that the user can drag Vertices around the screen and later remove and more.
I am stuck at this point where i want to paint more then one Vertex, and am trying to avoid making JVM paint the whole graph all over again when the graph changes.
do i have to make it paint the whole graph or is there another way to do that?
here's my code:
class GraphPanel extends JPanel {
private static final long serialVersionUID = 1L;
private Vector<Vertex> V=new Vector<Vertex>();
private Vertex v;
private int R = 20;
public GraphPanel() {
V.add(new Vertex(70,70));
V.add(new Vertex(10,50));
paintGraph();
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
for (int i=0;i<V.size();i++) {
if ((V.get(i).getX()<=e.getX() && V.get(i).getX()+R>=e.getX()) && ( V.get(i).getY()<=e.getY() && V.get(i).getY()+R>=e.getY())) {
v=V.get(i);
moveVertex(e.getX(),e.getY());
v.changeState();
}
}
}
public void mouseReleased(MouseEvent e) {
v.changeState();
}
});
addMouseMotionListener(new MouseAdapter() {
public void mouseDragged(MouseEvent e) {
if (v.isPressed()) moveVertex(e.getX(),e.getY());
}
});
}
private void paintGraph() {
int OFFSET = 1;
for (int i=0;i<V.size();i++) {
v=V.get(i);
repaint(v.getX(),v.getY(),R+OFFSET,R+OFFSET);
}
}
private void moveVertex(int x, int y) {
int OFFSET = 1;
if ((v.getX()!=x) || (v.getY()!=y)) {
repaint(v.getX(),v.getY(),R+OFFSET,R+OFFSET);
v.setLocation(x-10, y-10);
repaint(v.getX(),v.getY(),R+OFFSET,R+OFFSET);
}
}
public Dimension getPreferredSize() {
return new Dimension(250,200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (v!=null) {
g.setColor(Color.RED);
g.fillOval(v.getX(),v.getY(),R,R);
g.setColor(Color.BLACK);
g.drawOval(v.getX(),v.getY(),R,R);
}
}
}
public class Vertex {
private int x,y;
boolean isPressed;
Vertex(int x0,int y0) {x=x0;y=y0;isPressed=false;}
public void setLocation(int x0,int y0) {x=x0;y=y0;}
public int getX() {return x;}
public int getY() {return y;}
public boolean isPressed() {return isPressed;}
public boolean changeState() {return isPressed=!isPressed;}
}
public class Tester {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
JFrame f = new JFrame("Swing Paint Demo");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new GraphPanel());
f.pack();
f.setVisible(true);
}
}

Let's consider graph is list of Ovals and list of Lines. IN the paintComponent() method of Graph we have to draw all the lists' members.
Add a check that g.getClipBounds rectangle intersects Oval (or Line) rectangle. If they intersect we draw oval or line.
When vertex is moved somewhere we have old and new position and can get rectangle to be repainted.
Use the rectangle location and size and pass in the graph panel's repaint().
That way you will repaint changed region only and only ovals and lines visible in the rectangle.

This example can easily handle thousands of vertices. Larger numbers may benefit from using the flyweight pattern for rendering; one approach is illustrated here.

Related

Why the menubar is displayed twice, and the drawn lines only appear on a quarter of the page? [closed]

Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Closed 2 years ago.
Improve this question
I am learning Java. And I have a problem, certainly basic.
The menubar is displayed twice, and the drawn lines only appear on a quarter of the page.
Do you think there is a relation between the Panel and the JMenuBar ?
Do you think the problem is related to the repaint() method ?
Here is the code :
Class panel:
public class Panel extends JPanel {
private String colorName = "All";
private Color color = Color.RED;
private String shape = "Circle";
private int size1 = 30;
private int x = 0, y = 0;
private boolean allow = false;
#Override
public void paintComponent(Graphics g) {
// TODO Auto-generated method stub
super.paintComponent(g);
if (allow == true) {
if (colorName == "Red")
g.setColor(Color.RED);
else if (colorName == "Blue")
g.setColor(Color.BLUE);
else if (colorName == "All") {
int r = (int) ((Math.random()) * 256);
int v = (int) ((Math.random()) * 256);
int b = (int) ((Math.random()) * 256);
color = new Color(r, v, b);
g.setColor(color);
}
if (shape == "Circle")
g.fillOval(x, y, size1, size1);
if (shape == "Square")
g.fillRect(x, y, size1, size1);
}
repaint();
}
public String getColorName() {
return colorName;
}
public void setColorName(String colorName) {
this.colorName = colorName;
}
public boolean isAllow() {
return allow;
}
public void setAllow(boolean allow) {
this.allow = allow;
}
public String getShape() {
return shape;
}
public void setForme(String forme) {
this.shape = shape;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public int getSize1() {
return size1;
}
public void setSize1(int size1) {
this.size1 = size1;
}
}
Class frame :
public class Frame extends JFrame{
JMenuBar mb = new JMenuBar();
JMenu file = new JMenu("File");
JMenu edit = new JMenu("Edit");
Panel p = new Panel();
public Frame() {
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setSize(400,400);
this.setTitle("Test");
this.addMouseListener(new MouseAdapter(){
#Override
public void mousePressed(MouseEvent e) {
int a = e.getX() - (p.getSize1()/2);
int b = e.getY() - (p.getSize1());
p.setX(a);
p.setY(b);
p.setAllow(true);
}
});
this.addMouseMotionListener(new MouseMotionListener() {
#Override
public void mouseMoved(MouseEvent e) {
}
#Override
public void mouseDragged(MouseEvent e) {
int a = e.getX() - (p.getSize1()/2);
int b = e.getY() - (p.getSize1());
p.setX(a);
p.setY(b);
p.setAllow(true);
}
});
mb.add(file);
mb.add(edit);
this.setJMenuBar(mb);
this.setLayout(new BorderLayout());
this.add(p, BorderLayout.CENTER);
this.setVisible(true);
}
public static void main(String[] args) {
new Frame();
}
}
Can you help me please?
You've a very bad typographical bug in your code:
#Override
public void paintComponent(Graphics g) {
// TODO Auto-generated method stub
super.paintComponents(g);
should be:
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Please note the difference in the super call since paintComponents != paintComponent
Also, don't compare Strings using == or !=. Use the equals(...) or the equalsIgnoreCase(...) method instead. Understand that == checks if the two object references are the same which is not what you're interested in. The methods on the other hand check if the two Strings have the same characters in the same order, and that's what matters here.
And so, not:
if (colorName == "Red") {
// ....
}
but rather:
if (colorName.equalsIgnoreCase("Red")) {
// ....
}
Also, never call repaint() within a painting method. Also, don't randomize the painting or change object state within paintComponent since you do not have control over when or if the method will be called. Randomize in a listener, such as the mouse listener, and if you need animation separate from what the mouse listener provides, use a Swing Timer
ALSO
This:
public int getX() {
// ...
}
Overrides a key method of JPanel inherited from the Component class, that is key to placement of the JPanel, same for getY(). Rename those methods ASAP

Drawing shape on mouse drag

class MyPanel extends JPanel implements Observer, MouseMotionListener, MouseListener {
private MyModel model;
private View view;
private String mode;
private Rectangle rectangle;
private Square square;
public MyPanel(MyModel model, View view) {
this.setBackground(Color.black);
this.setPreferredSize(new Dimension(300, 300));
this.addMouseListener(this);
this.addMouseMotionListener(this);
this.model = model;
this.model.addObserver(this);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
ArrayList<Rectangle> rectangles = this.model.getRectangles();
for (Rectangle r : getRectangles()) {
int width = Math.abs(r.getStartPoint().getX() - r.getEndPoint().getX());
int height = Math.abs(r.getStartPoint().getY() - r.getEndPoint().getY());
}
ArrayList<Square> squares = this.model.getSquares();
for (Square sqr : getSquares()) {
int xPosition = Math.min(sqr.getStartPoint().getX(), sqr.getEndPoint().getX());
int yPosition = Math.min(sqr.getStartPoint().getY(), sqr.getEndPoint().getY());
int width = Math.abs(sqr.getStartPoint().getX() - sqr.getEndPoint().getX());
int height = Math.abs(sqr.getStartPoint().getY() - sqr.getEndPoint().getY());
}
g2d.dispose();
}
public void update(Observable o, Object arg) {
this.repaint();
}
#Override
public void mouseDragged(MouseEvent e) {
if (this.mode.equals("Rectangle")) {
this.rectangle.setEndPoint(e.getX(), e.getY());
this.model.addRectangle(this.rectangle);
}
else if (this.mode.equals("Square")) {
// What code should I add here?
this.model.addSquare(this.square);
}
}
// MouseListener below
#Override
public void mouseClicked(MouseEvent e) {}
#Override
public void mousePressed(MouseEvent e) {
if (this.mode.equals("Rectangle")) {
this.rectangle = new Rectangle(e.getX(), e.getY());
}
else if (this.mode.equals("Square")) {
this.square = new Square(e.getX(), e.getY());
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (this.mode.equals("Rectangle")) {
this.rectangle.setEndPoint(e.getX(), e.getY());
this.model.addRectangle(this.rectangle);
this.rectangle = null;
}
else if (this.mode.equals("Square")) {
this.model.addSquare(this.square);
this.square = null;
}
}
#Override
public void mouseEntered(MouseEvent e) {}
#Override
public void mouseExited(MouseEvent e) {}
}
The user chooses a mode, rectangle or square. Then they can draw a square or a rectangle with their mouse (live feedback is shown). Here is my drawing panel class. I was successfully able to implement the rectangle mode. The user can draw a rectangle and as they move their mouse, the rectangle is shown in mid construction. I want to do the same for the square mode. For some reason, I'm having a hard time doing this. How would I show a perfect square in mid construction when the user is moving their mouse and how would I draw it once released? What code should I add to my paintComponent method, mouseDragged, mousePressed and mouseReleased method to do this? It was easy for a rectangle because there was no constraint but I'm not sure how to do it for a square with my current implementation.
int width = Math.abs(r.getStartPoint().getX() - r.getEndPoint().getX());
int height = Math.abs(r.getStartPoint().getY() - r.getEndPoint().getY());
I would guess that the "size" of the square would be the maximum of the above two values.
Then I would think you would just use:
r.drawStyle(g2d, xPosition, yPosition, size, size);

can't draw on a JPanel after repaint method

I'm experimenting on a GUI that I programmed and I don't understand how I can fix my problem:
My GUI contains a jPanel that on receiving a mouseclick, paints a point with filloval command.
private void myPnlMousePressed(java.awt.event.MouseEvent evt) {
changed = true;
p.x = evt.getX();
p.y = evt.getY();
drewPoints(p.x, p.y);
}
private void drewPoints (int x, int y) {
if (gf == null) {
gf = (Graphics)myPnl.getGraphics();
}
myPointsList.add(new Point(x, y));
gf.fillOval(x, y, 5, 5);
xVal.setText("X = " + x);
yVal.setText("Y = " + y);
}
everything works fine but when I want to open an XML file that I created to save all the points it doesn't work.
The problem is that when I use the repaint method on the jPanel after choosing a file, all the points loads fine but the panel can't draw the points.
If I put the repaint method in the open button listener (before the choosing file) it works, but then if the user cancels the open option so the panel stays blank and I don't want to draw the points again.
I think it happens because the repaint process is not finished.
All the points added to a private List.
private void OpenFile() {
try {
File thisFile;
JFileChooser of = new JFileChooser();
int option = of.showOpenDialog(of);
if (option == JFileChooser.APPROVE_OPTION){
thisFileName = of.getSelectedFile().getPath();
thisFile = new File(thisFileName);
if (!of.getSelectedFile().getName().endsWith(".xml")) {
String error = "Error, You didn't select XML file";
JOptionPane.showMessageDialog(this, error, "Wrong type of file", JOptionPane.INFORMATION_MESSAGE);
return;
}
myPnl.repaint();
myPointsList.clear();
....
....
....
for (int i = 0; i < pointsList.getLength(); i++) {
Element point = (Element) pointsList.item(i);
p.x = Integer.parseInt(point.getElementsByTagName("X").item(0).getTextContent());
p.y = Integer.parseInt(point.getElementsByTagName("Y").item(0).getTextContent());
drewPoints(p.x, p.y);
}
....
how can I make it work??
Don't use gf = (Graphics)myPnl.getGraphics();, this is not how painting in Swing works. The getGraphics method can return null and is nothing more then a snap shot of the last paint cycle, any thing you paint to it will be erased on the next paint cycle (repaint).
Instead, override the JPanels paintComponent and put all you painting logic there. There is an expectation that when called, you are expected to fully re-paint the current state of the component.
See Painting in AWT and Swing and Performing Custom Painting for more details about how painting works in Swing
You have to use the repaint() and override the paint() method:
class MyPanel extends JPanel implements MouseListener
{
private int x;
private int y;
public MyPanel() {
super();
addMouseListener(this);
}
#Override public void mouseEntered(MouseEvent e) { }
#Override public void mouseExited(MouseEvent e) { }
#Override public void mouseClicked(MouseEvent e) { }
#Override public void mousePressed(MouseEvent e) { }
#Override public void mouseReleased(MouseEvent e) {
x = e.getX();
y = e.getY();
repaint();
}
#Override public void paint(Graphics g) {
super.paint(g);
g.fillOval(x, y, 10, 10);
}
}
If you want to draw all points, don't use x and y but a list of points:
class MyPanel extends JPanel implements MouseListener
{
private ArrayList<Point> points = new ArrayList<>();
public MyPanel() {
super();
addMouseListener(this);
}
#Override public void mouseEntered(MouseEvent e) { }
#Override public void mouseExited(MouseEvent e) { }
#Override public void mouseClicked(MouseEvent e) { }
#Override public void mousePressed(MouseEvent e) { }
#Override public void mouseReleased(MouseEvent e) {
points.add(new Point(e.getX(), e.getY()));
repaint();
}
#Override public void paint(Graphics g) {
super.paint(g);
for (Point p : points)
g.fillOval(p.getX(), p.getY(), 10, 10);
}
}
where:
class Point
{
private int x;
private int y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
Then use it:
public static void main(String[] args) {
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
MyPanel myPanel = new MyPanel();
frame.add(myPanel);
frame.setVisible(true);
}

Adding JPanel after removing it from JFrame

I'm developing a Java Game. I'm stuck at a point,where I need to restart the whole game again after GameOver. Here is the skeleton of my program:
package projectflappy;
import java.awt.*;
public final class TheGame extends JFrame implements MouseListener{
JPanel jp;
//declaration of the varibles
int x_width = 500;
int y_height = 500;
int count = 5 ;
Ellipse2D Ball;
int x_ball;
int y_ball;
int cord_xup1,cord_xdown1;
int cord_xup2,cord_xdown2;
int cord_xup3,cord_xdown3;
int cord_xup4,cord_xdown4;
int cord_xup5,cord_xdown5;
Boolean flag = true;
RoundRectangle2D up1,down1,up2,down2,up3,down3,up4,down4;
Font font = new Font("Matura MT Script Capitals",Font.ROMAN_BASELINE,40);
Font font1 = new Font("Matura MT Script Capitals",Font.ROMAN_BASELINE,20);
Font font3 = new Font("Matura MT Script Capitals",Font.ROMAN_BASELINE,20);
float das[] = {10.0f};
BasicStroke color = new BasicStroke(10,BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL,20.0f,das,0.0f);
GradientPaint gp2 = new GradientPaint(20, 0,
Color.DARK_GRAY, 0, 10, Color.GRAY, true);
GradientPaint gp3 = new GradientPaint(30, 0,
Color.BLACK, 0, 20, Color.GREEN, true);
Toolkit kit = Toolkit.getDefaultToolkit();
//Getting the "background.jpg" image we have in the folder
Image background = kit.getImage("D:\\College\\Programs\\ProjectFLAPPY\\src\\projectflappy\\1.png");
JLabel a = new JLabel("Get Ready ! Click to Start.");
JLabel retry = new JLabel(new ImageIcon("D:\\College\\Programs\\ProjectFLAPPY\\src\\projectflappy\\unnamed.png"));
int score = 0;
//constructor
public TheGame() throws IOException
{
super("Simple Drawing");
setSize(x_width, y_height);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
jp = new DrawingPanel();
add(jp);
addMouseListener(this);
}
ActionListener action = new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
update();
repaint();
}
};
Timer t = new Timer(50,action);
public void init()
{
x_ball = 30;
y_ball = 200;
cord_xup1 = 175; cord_xdown1 = 175;
cord_xup2 = 320; cord_xdown2 = 320;
cord_xup3 = 460; cord_xdown3 = 460;
cord_xup4 = 585; cord_xdown4 = 585;
cord_xup5 = 700; cord_xdown5 = 700;
retry.setVisible(false);
retry.setBounds(175,260,46,46);
a.setForeground(Color.YELLOW);
a.setFont(font1);
a.setVisible(true);
a.setBounds(105,200,300,100);
}
#Override
public void mouseClicked(MouseEvent e) {
//throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
a.setVisible(false);
if( flag == false)
{
t.stop();
}
else
{
t.start();
}
y_ball = y_ball - 40;
count--;
}
#Override
public void mousePressed(MouseEvent e) {
//throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
#Override
public void mouseReleased(MouseEvent e) {
//throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
#Override
public void mouseEntered(MouseEvent e) {
//throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
#Override
public void mouseExited(MouseEvent e) {
//throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
// for drawing on the panel
class DrawingPanel extends JPanel{
private static final long serialVersionUID = 1L;
public DrawingPanel() {
setPreferredSize(new Dimension(300, 300));
setLayout(null);
init();
add(a);
add(retry);
// addMouseListener(this);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D d = (Graphics2D)g;
d.drawImage(background, -270,-30, this);
Ball = new Ellipse2D.Double(x_ball,y_ball,30,30);
d.setColor(Color.green);
d.setFont(font3);
up1 = new RoundRectangle2D.Double(cord_xup1,-5,30,175,20,20);
down1 = new RoundRectangle2D.Double(cord_xdown1,310,30,155,20,20);
up2 = new RoundRectangle2D.Double(cord_xup2,-5,30,200,20,20);
down2 = new RoundRectangle2D.Double(cord_xdown2,310,30,175,20,20);
up3 = new RoundRectangle2D.Double(cord_xup3,-5,30,230,20,20);
down3 = new RoundRectangle2D.Double(cord_xdown3,350,30,135,20,20);
up4 = new RoundRectangle2D.Double(cord_xup4,-5,30,115,20,20);
down4 = new RoundRectangle2D.Double(cord_xdown4,240,30,115,20,20);
d.setPaint(gp2);
d.setStroke(color);
d.fill(up1);
d.fill(down1);
d.fill(up2);
d.fill(down2);
d.fill(up3);
d.fill(down3);
d.fill(up4);
d.fill(down4);
d.setPaint(gp3);
d.setStroke(color);
d.fill(Ball);
d.setColor(Color.BLACK);
d.setFont(font1);
d.drawString(""+score ,200,50);
if( Ball.intersects(up1.getBounds()) || Ball.intersects(down1.getBounds()) || Ball.intersects(up2.getBounds()) || Ball.intersects(down2.getBounds()) || Ball.intersects(up3.getBounds()) || Ball.intersects(down3.getBounds()) || Ball.intersects(up4.getBounds()) || Ball.intersects(down4.getBounds()))
{
t.stop();
flag = false;
d.setColor(Color.red);
d.setFont(font);
d.drawString("Game Over : "+score ,100,250);
retry.setVisible(true);
}
retry.addMouseListener(new MouseListener() {
#Override
public void mouseClicked(MouseEvent event) {
init(); //reset properties
}
//...
#Override
public void mousePressed(MouseEvent e) {
// throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
#Override
public void mouseReleased(MouseEvent e) {
// throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
#Override
public void mouseEntered(MouseEvent e) {
// throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
#Override
public void mouseExited(MouseEvent e) {
// throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
});
}
}
public void update()
{
cord_xdown1 -= 5;
cord_xup1 -= 5;
cord_xdown2 -= 5;
cord_xup2 -= 5;
cord_xdown3 -= 5;
cord_xup3 -= 5;
cord_xdown4 -= 5;
cord_xup4 -= 5;
cord_xdown5 -= 5;
cord_xup5 -= 5;
if( cord_xup1 <=-20)
{
cord_xup1 = 500;
cord_xdown1 = 500;
}
if( cord_xup2 <=-20)
{
cord_xup2 = 500;
cord_xdown2 = 500;
}
if( cord_xup3 <=-20)
{
cord_xup3 = 500;
cord_xdown3 = 500;
}
if( cord_xup4 <=-20)
{
cord_xup4 = 500;
cord_xdown4 = 500;
}
if( cord_xup5 <=-20)
{
cord_xup5 = 500;
cord_xdown5 = 500;
}
if(count >= 0)
{
y_ball = y_ball - 7;
count--;
if( y_ball == y_height)
{
t.stop();
}
}
else
{
y_ball = y_ball + 7;
if( y_ball == y_height-70)
{
t.stop();
}
}
if(cord_xdown1 == x_ball || cord_xdown2 == x_ball || cord_xdown3 == x_ball || cord_xdown4 == x_ball)
{
score = score+1;
}
}
public static void main(String[] args) throws IOException {
new TheGame();
}
}
here retry is a JLabel in which I'm using a MouseListener to do things.
When I run,the JPanel gets completely removed from the JFrame but the new JPanel really doesn't seem to work. But only one component i.e, a.setVisble(true) works.
This is the frame when the Players gets out.
This Frames when the Player clicks on the retry button.
The reason your new panel is not showing is due to the component hierarchy being invalid. You attempt to revalidate, but you did it before adding the panel. You need to do it AFTER you add a component to an already visible container. Check out invalidate():
This method is called automatically when any layout-related information changes (e.g. setting the bounds of the component, or adding the component to a container).
So you must validate after adding the component, not before. revalidate() invalidates then revalidates the component hierarchy.
The proper way to handle this would be to revert your game back to it's original form; just change everything back to how it was. No need to create a new panel.
You could create a method, init(), which sets your game to how it should be:
//Contains the properties that will change during gameplay
void init() {
retry.setVisible(false);
a.setForeground(Color.YELLOW);
//...
}
Which you can then call when you create the board (in the constructor) and when you press retry (in the listener):
public DrawingPanel() {
setPreferredSize(new Dimension(300, 300));
setPreferredSize(new Dimension(300, 300));
setLayout(null);
init(); //sets properties
a.setFont(font1);
a.setVisible(true);
a.setBounds(105,200,300,100);
add(a);
retry.setBounds(175,260,46,46);
retry.addMouseListener(new MouseListener() {
public void mouseClicked(MouseEvent event) {
init(); //reset properties
}
//...
});
add(retry);
}
You shouldn't add a listener to a component in your update() method, since update() will be called multiple times. Add it in your constructor.
If retry is a JButton, you should use an ActionListener. I wasn't sure, so I kept it as a mouse listener.
You should avoid using null layout (absolute positioning). Layout Managers position and size components using specific calculations to ensure your resulting GUI looks the same on all platforms. There are a few uses where absolute positioning is a viable option, as mentioned in the tutorials, but it's always best to prefer a Layout Manager. IMO, null layout is bad practice, and the only reason one would use it is if they didn't understand layout managers, which is a problem in itself.
To learn more about layout managers, check out the Visual Guide to Layout Managers trail. Not only does the JDK come bundled with layouts, but you can also create your own or use a third party layout, like MigLayout
EDIT:
Post Swing code to the Event Dispatch Thread. Swing event handlers (painting, listeners) are executed on the Event Dispatch Thread. To ensure the Swing code you write is in sync with the EDT, post any Swing code that isn't already being executed on the EDT to the EDT by using invokeLater or invokeAndWait.
Do not size your frame directly. Allow your frame to size based off the contents inside of it. Your DrawingPanel (the game canvas) should determine the size of the frame.
TheGame should not extend JFrame, since it's not a frame itself, rather than something contained within a frame. Having it extend JPanel would be a little easier on you (you won't be forced to create a new class to override the paint method). Although, TheGame shouldn't extend anything, it should HAVE these things (has-a relationship, not is-a). But since you're still a beginner, I don't wanna overwhelm you with a completely new design, so I considered TheGame to be the actual game canvas (where things will be draw; TheGame will extend JPanel), so you'll no longer need DrawingBoard.
As mentioned before, you should NOT add listeners (or do any task that is only needed once) in the paint method. Keep in mind that the paint method is for painting, not initializing or setting values. You should attempt to keep logic out of that method if possible.
Stay consistent. You use a JLabel for "Click to start!", yet you use drawString for "Game Over". Pick one or the other. This choice is really up to you. For this example, I chose to use drawString, since it's consistent with the rest of your rendering methods (how you paint the background, ball and obstacles)
DO NOT CREATE NEW OBJECTS IN YOUR PAINT METHOD. You're creating a ton of new objects every 50 milliseconds. This is NOT needed, and will harm performance critically. When you use the new keyword, you create a new object. Instead of creating a new object to change it (or revert it back), just change it's state.
Take advantage of Object Orientation. It'll help keep you organized, and allow you to easily manage and scale up your application. Don't shove a bunch of variables into one class to represent a ton of different things (cordx_up1, cordx_up2... it's definitely not scalable).
Look into some of the Adapter classes like MouseAdapter and KeyAdapter; they allow you to handle events without needing to declare methods you might not use.
Use access modifiers. If you aren't familiar with them, get to know them. It makes managing code a lot easier if you know where it can be used ahead of time.
Your paths point to a specific drive with a specific name. This should not be the case, since not everyone uses that drive and/or folder name. Package your images with your project, then refer to them locally.
With that said, you have a lot of studying to do.
What I did was create a Ball class and an Obstacle class, to get a little more organized. ball_x and ball_y are now inside the Ball class, as well as the gradient for it. The objects we create from this class will now have these properties (states). I create 1 ball object for your game.
Instead of creating new variables for each pole (cordx_up1), the Obstacle class has 2 RoundRectangle2D, top and bottom, which are the poles your ball is supposed to avoid. Each obstacle also has a gradient, which is used for both top and bottom. Now I can create 1 obstacle object for 2 aligned poles. You can change the starting x position of the obstacle (although I don't recommend allowing this; x should be set dynamically based on other obstacles' positions), as well as the size for top and bottom. I create 5 obstacle objects.
To keep your game labels organized (by color, message, location, font) while using drawString instead of JLabel, I created a GameLabel class.
I separated the main method into it's own class, named Launcher, which creates a JFrame and adds your game to it; all on the Event Dispatch Thread:
public class Launcher {
public static void main(String[] args) throws IOException {
EventQueue.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.add(new TheGame());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
});
}
}
Your Game class now extends JPanel, so you can override the paint method to render the game. I created 1 Ball and a LinkedList for your obstacles. I chose a LinkedList since inserting/removing from front/end is guaranteed constant time, meaning it'll take the same amount of time to remove/insert no matter how many obstacles are in the list. When the ball passes an obstacle, I remove it from the front of the list and add it to the back. The first obstacle in the list is always the next obstacle.
I saw how some Strings were being re-used, so I created final variables for them, which you can easily change. There's also the currentlyPlaying and isAlive booleans. currentlyPlaying is set to true when the user first clicks (to start the game), and set to false once the user has clicked to restart the game (after he lost).
readyToJump is the flag I use to forward mouse events to your update() method (technically your updatePlayerPostion() method, but it's still "centeralized" within your update() method). It's best to keep all your logic in one place. readyToJump = true would have been the only statement in your listener's method if you weren't relying on calling timer.start() in it. Since update() can't be called unless the timer has started, and mouseEvent starts the timer, we must still handle starting the game in your listener's method.
#SuppressWarnings("serial")
public final class TheGame extends JPanel implements MouseListener, ActionListener {
public static final int WIDTH = 500, HEIGHT = 500;
private final String START_SCORE = "0",
START_MESSAGE = "Get Ready ! Click to Start.",
BACKGROUND_URL = "/res/flappy.png";
private boolean currentlyPlaying, readyToJump, isAlive = true;
private int score;
private Timer timer;
private Image background;
private GameLabel messageLabel, scoreLabel;
private Collection<Obstacle> obstaclesInOrder;
private LinkedList<Obstacle> obstacles;
private Ball ball;
public TheGame() {
setPreferredSize(new Dimension(WIDTH, HEIGHT));
addMouseListener(this);
timer = new Timer(50, this);
background = loadBackgroundImage();
messageLabel = new GameLabel(START_MESSAGE, 150, 240);
scoreLabel = new GameLabel(START_SCORE, 250, 60);
obstacles = new LinkedList<>();
obstacles.removeAll(obstacles);
obstaclesInOrder = Arrays.asList(new Obstacle(175, 20, 45), new Obstacle(320), new Obstacle(460), new Obstacle(585), new Obstacle(700));
obstacles.addAll(obstaclesInOrder);
ball = new Ball(30, 100);
}
#Override
public void mouseClicked(MouseEvent e) {
if (!currentlyPlaying) {
startGame();
} else if (!isAlive) {
reset();
}
readyToJump = true;
}
private void startGame() {
currentlyPlaying = true;
messageLabel.update("");
timer.start();
}
private void endGame() {
isAlive = false;
scoreLabel.update("");
messageLabel.update("Game Over. Your score was " + Integer.toString(score));
timer.stop();
}
private void reset() {
ball.reset();
for (Obstacle obstacle : obstacles)
obstacle.reset();
messageLabel.update(START_MESSAGE, 150, 240);
scoreLabel.update(START_SCORE, 250, 60);
obstacles.removeAll(obstacles);
obstacles.addAll(obstaclesInOrder);
score = 0;
isAlive = true;
currentlyPlaying = false;
repaint();
}
#Override
public void actionPerformed(ActionEvent ae) {
update();
repaint();
}
private void update() {
if (isAlive) {
updateBallPosition();
updateObstaclePositions();
if(ballOutOfBounds() || playerCollidedWithObstacle()) {
endGame();
} else if(ballPassedObstacle()) {
addToScore();
setupNextObstacle();
}
}
}
private void updateBallPosition() {
if (readyToJump) {
readyToJump = false;
ball.jump();
} else {
ball.fall();
}
}
private void updateObstaclePositions() {
for (Obstacle obstacle : obstacles) {
if (obstacle.getX() <= -obstacle.getWidth()) {
obstacle.moveToBack();
continue;
}
obstacle.moveForward();
}
}
private void addToScore() {
scoreLabel.update(Integer.toString(++score));
}
private void setupNextObstacle() {
obstacles.addLast(obstacles.removeFirst());
}
private boolean ballOutOfBounds() {
return ball.getY() >= HEIGHT || ball.getY() <= 0;
}
private boolean ballAtObstacle() {
Obstacle currentObstacle = obstacles.getFirst();
return ball.getX() + ball.getWidth() >= currentObstacle.getX() && ball.getX() <= currentObstacle.getX() + currentObstacle.getWidth();
}
private boolean ballPassedObstacle() {
Obstacle currentObstacle = obstacles.getFirst();
return ball.getX() >= (currentObstacle.getX() + currentObstacle.getWidth());
}
private boolean playerCollidedWithObstacle() {
boolean collided = false;
if(ballAtObstacle()) {
for (Obstacle obstacle : obstacles) {
RoundRectangle2D top = obstacle.getTop();
RoundRectangle2D bottom = obstacle.getBottom();
if (ball.intersects(top.getX(), top.getY(), top.getWidth(), top.getHeight()) || ball.intersects(bottom.getX(), bottom.getY(), bottom.getWidth(), bottom.getHeight())) {
collided = true;
}
}
}
return collided;
}
private Image loadBackgroundImage() {
Image background = null;
URL backgroundPath = getClass().getResource(BACKGROUND_URL);
if(backgroundPath == null) {
background = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
} else {
try {
background = ImageIO.read(backgroundPath);
} catch (IOException e) {
e.printStackTrace();
}
}
return background;
}
#Override
public void paintComponent(Graphics graphics) {
super.paintComponent(graphics);
Graphics2D g = (Graphics2D) graphics;
g.drawImage(background, 0, 0, null);
ball.paint(g);
for (Obstacle obstacle : obstacles)
obstacle.paint(g);
scoreLabel.paint(g);
messageLabel.paint(g);
}
//...
}
loadBackgroundImage() loads and returns an image. If a problem occurs (image probably isn't there), it returns a black image.
(Most of) The game logic is in the update() method. Although it should all be in there, we can't due to a design flaw (from you using Timer which manages update(), and you start the timer in a listener, therefore we needed some logic in the listener). Your logic should be easy to read, and every execution step should be monitored and set by highest priority to lowest.
First, I check to make sure the ball hasn't collided with anything or gone out of bounds. If one of those things occur, I end the game.
If not, I check to see if the player has passed an obstacle. If the player passes an obstacle, I add to the score:
private void update() {
if (ballOutOfBounds() || playerCollidedWithObstacle()) {
endGame();
} else if (ballPassedObstacle()) {
addToScore();
setupNextObstacle();
}
updateBallPosition();
updateObstaclePositions();
}
I then finally update the positions.
To avoid constantly comparing the player's position and the obstacle's position (to see if the player has passed it), I created a boolean ballAtObstacle() method, which checks if the player is at an obstacle. Only then do I compare positions:
private boolean playerCollidedWithObstacle() {
boolean collided = false;
if (ballAtObstacle()) {
for (Obstacle obstacle : obstacles) {
RoundRectangle2D top = obstacle.getTop();
RoundRectangle2D bottom = obstacle.getBottom();
if (ball.intersects(top.getX(), top.getY(), top.getWidth(), top.getHeight()) || ball.intersects(bottom.getX(), bottom.getY(), bottom.getWidth(), bottom.getHeight())) {
collided = true;
}
}
}
return collided;
}
The ball.intersects method call is a bit messy. I did this so the shape didn't have to be specific, although you could declare the intersects method as boolean intersects(Shape shape).
Finally, I gave it a more flappy bird feel by increasing the fall speed as you fall. When you jump again, it goes back to normal. The longer it takes you to jump, the faster you'll fall. If you don't like this feature, and don't know how to remove it, let me know and I'll show you how.
The other classes involved:
GameLabel.java
public class GameLabel {
private String message;
private Font font;
private Color color;
private int x, y;
public GameLabel(String message, int x, int y, Color color, Font font) {
update(message, x, y, color, font);
}
public GameLabel(String message, int x, int y) {
this(message, x, y, Color.BLACK, new Font("Matura MT Script Capitals", Font.ROMAN_BASELINE, 20));
}
public GameLabel() {
this("", 0, 0);
}
public void setMessage(String message) {
this.message = message;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
public void setColor(Color color) {
this.color = color;
}
public void setFont(Font font) {
this.font = font;
}
public final void update(String message, int x, int y, Color color, Font font) {
this.message = message;
this.x = x;
this.y = y;
this.color = color;
this.font = font;
}
public void update(String message, int x, int y) {
update(message, x, y, color, font);
}
public void update(String message) {
update(message, x, y);
}
public void paint(Graphics2D g) {
g.setFont(font);
g.setColor(color);
g.drawString(message, x, y);
}
public Font getFont() {
return font;
}
public Color getColor() {
return color;
}
public String getMessage() {
return message;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
Obstacle.java
public class Obstacle {
public static final int DEFAULT_TOP_HEIGHT = 175;
public static final int DEFAULT_BOTTOM_HEIGHT = 175;
public static final int DEFAULT_WIDTH = 30;
public static final int DEFAULT_ARCH_WIDTH = 20;
public static final int DEFAULT_ARCH_HEIGHT = 20;
public static final int DEFAULT_TOP_INSET = -5;
public static final int DEFAULT_BOTTOM_INSET = TheGame.HEIGHT + 5;
private RoundRectangle2D top, bottom;
private BasicStroke stroke;
private GradientPaint gradient;
private int initialX, x, width;
public Obstacle(int x, int width, int topHeight, int bottomHeight) {
this.x = initialX = x;
this.width = width;
top = new RoundRectangle2D.Double(x, DEFAULT_TOP_INSET, width, topHeight, DEFAULT_ARCH_WIDTH, DEFAULT_ARCH_HEIGHT);
bottom = new RoundRectangle2D.Double(x, DEFAULT_BOTTOM_INSET-bottomHeight, width, bottomHeight, DEFAULT_ARCH_WIDTH, DEFAULT_ARCH_HEIGHT);
stroke = new BasicStroke(10, BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL, 20.0f, new float[] { 10.0f }, 0.0f);
gradient = new GradientPaint(20, 0, Color.DARK_GRAY, 0, 10, Color.GRAY, true);
}
public Obstacle(int x, int topHeight, int bottomHeight) {
this(x, DEFAULT_WIDTH, topHeight, bottomHeight);
}
public void reset() {
x = initialX;
top.setRoundRect(initialX, top.getY(), top.getWidth(), top.getHeight(), top.getArcWidth(), top.getArcHeight());
bottom.setRoundRect(initialX, bottom.getY(), bottom.getWidth(), bottom.getHeight(), bottom.getArcWidth(), bottom.getArcHeight());
}
public Obstacle(int x, int width) {
this(x, width, DEFAULT_TOP_HEIGHT, DEFAULT_BOTTOM_HEIGHT);
}
public Obstacle(int x) {
this(x, DEFAULT_WIDTH);
}
public void moveToBack() {
x = 600;
}
public void moveForward() {
x -= 5;
top.setRoundRect(x, top.getY(), top.getWidth(), top.getHeight(), top.getArcWidth(), top.getArcHeight());
bottom.setRoundRect(x, bottom.getY(), bottom.getWidth(), bottom.getHeight(), bottom.getArcWidth(), bottom.getArcHeight());
}
public RoundRectangle2D getTop() {
return top;
}
public RoundRectangle2D getBottom() {
return bottom;
}
public int getX() {
return x;
}
public int getWidth() {
return width;
}
public void paint(Graphics2D g) {
g.setPaint(gradient);
g.setStroke(stroke);
g.fill(top);
g.fill(bottom);
}
}
Ball.java
public class Ball {
public static final int DEFAULT_DROP_SPEED = 7;
private Ellipse2D ball;
private GradientPaint gradient;
private int initialY, x, y, width = 30, height = 30, dropSpeed = DEFAULT_DROP_SPEED;
public Ball(int x, int y) {
this.x = x;
this.y = initialY = y;
width = height = 30;
ball = new Ellipse2D.Double(x, y, width, height);
gradient = new GradientPaint(30, 0, Color.BLACK, 0, 20, Color.GREEN, true);
}
public void reset() {
y = initialY;
updateBall();
}
public void jump() {
dropSpeed = DEFAULT_DROP_SPEED;
y -= 40;
updateBall();
}
public void fall() {
y += dropSpeed++;
updateBall();
}
private void updateBall() {
ball.setFrame(x, y, width, height);
}
public boolean intersects(double x, double y, double w, double h) {
return ball.intersects(x, y, w, h);
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getWidth() {
return width;
}
public int getHeight() {
return width;
}
public void paint(Graphics2D g) {
g.setPaint(gradient);
g.fill(ball);
}
public void moveForward() {
x += 7;
}
}
Reinitialize all the components by adding the initialization code to one method(resetAll) and call that method when u want to reinitailize
Below is an example:
import java.awt.*;
import java.awt.event.*;
public class ResetTest extends Frame{
Button b;
TextField tf;
Frame f;
Panel p;
public ResetTest(){
f=this; //intialize frame f to this to have access to our frame in event handler methods
resetAll(); //first time call to resetAll will initialize all the parameters of the frame
f.pack();
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent we){
System.exit(0);
}
});
this.setLayout(new FlowLayout(FlowLayout.CENTER,20,20));
this.setVisible(true);
}
/**
This method will be called on click of button to
reset all the parameters of the frame so that we
get fresh new frame, everything as it was before.
**/
public void resetAll(){
b=new Button("Reset");
p=new Panel(new FlowLayout(FlowLayout.CENTER,20,20));
p.add(b);
tf = new TextField("Edit And Reset");
p.add(tf);
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae){
remove(p); //remove the panel that contains all our components
resetAll(); // reset all the components
f.pack(); //refreshes the view of frame when everything is reset.
}
});
add(p);
}
}
class NewClass{
public static void main(String[] args) {
ResetTest fReset = new ResetTest();
}
}

Custom painting in Java - drawing UI elements onto the JPanel

I am creating a drawing board program, basically a simplified version of MS Paint. It is working for the most part but when I draw on the board, the currently selected UI element shows up on the drawing area.
I tried paintComponent, which worked when I called super.paintComponent(g) (as one does) but it cleared the drawing area before I drew the next object. I overrode update and put a println statement in there and it is never being called.
The buttons at the top are red because I set the background to the bottom JPanel to red to see what the background of these buttons would be. So clearly they are part of the bottom JPanel. I am using a BorderLayout for the layout.
Here is my code (with some irrelevant bits removed):
public class JSPaint extends JFrame implements Serializable
{
private static final long serialVersionUID = -8787645153679803322L;
private JFrame mainFrame;
private JPanel bp;
private JButton ...
private DrawingArea da;
public JSPaint()
{
setTitle("JS Paint");
setSize(1024, 768);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Drawing area
da = new DrawingArea();
setLayout(new BorderLayout());
// add the buttons to the panel
buttonPanel();
// Add the drawing area
add(bp, BorderLayout.SOUTH);
bp.setBackground(Color.RED);
add(da, BorderLayout.CENTER);
da.setBackground(Color.BLUE);
setVisible(true);
}
// I put it here too just in case
#Override
public void update(Graphics g)
{
System.out.println("update in JSPaint called.");
paint(g);
}
/*
* Creates the panel for the buttons, creates the buttons and places them on
* the panel
*/
public void buttonPanel()
{
// Create the panel for the buttons to be placed in
bp = new JPanel();
saveButton = new JButton("Save");
loadButton = new JButton("Load");
//more buttons
bp.add(saveButton);
bp.add(loadButton);
//more buttons
// ActionListeners
colorButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
System.out.println("color");
da.color();
}
});
}
public class DrawingArea extends JPanel
{
private static final long serialVersionUID = -8299084743195098560L;
boolean dragged = false;
#Override
public void update(Graphics g)
{
System.out.println("Update in DrawingArea called");
paint(g);
}
/*
* Draws the selected shape onto the screen and saves it into a Stack.
*
*/
public void draw()
{
this.addMouseMotionListener(new MouseMotionListener()
{
public void mouseDragged(MouseEvent me)
{
dragged = true;
}
public void mouseMoved(MouseEvent me) {}
});
//more listeners...
});
}
/*
* Draws the selected String onto the screen when the mouse is held down.
*
*/
public void brush()
{
this.addMouseMotionListener(new MouseMotionListener()
{
public void mouseDragged(MouseEvent me)
{
// If we are in drawing mode, draw the String. Create a new
// Figure Object and push it onto the Stack
if(activeButton == "brush")
{
startPoint = me.getPoint();
Figure fig = new Figure("String", startPoint, null, currentColor);
// figures.push(calculate(fig));
toPaint.push(calculate(fig));
repaint();
}
}
public void mouseMoved(MouseEvent me) {}
});
}
// more of the same...
public void paint(Graphics g)
{
toSave.addAll(toPaint);
while(!toPaint.isEmpty())
{
Figure f = toPaint.pop();
String t = f.type;
if(f.color != null)
{
g.setColor(f.color);
}
switch(t)
{
case "Rectangle": g.drawRect(f.x1, f.y1, f.width, f.height);
break;
case "Oval": g.drawOval(f.x1, f.y1, f.width, f.height);
break;
case "Line": g.drawLine(f.x1, f.y1, f.x2, f.y2);
break;
case "Clear":
g.fillRect(0, 0, da.getWidth(), da.getHeight());
clearStack(toSave);
break;
case "String": g.drawString(f.toPrint, f.x1, f.y1);
break;
}
}
}
}
private class Figure implements Serializable
{
private static final long serialVersionUID = 4690475365105752994L;
String type, toPrint;
Color color;
Point start;
Point end;
int x1, y1, x2, y2, width, height;
public Figure(String figureType,
Point startPoint, Point endPoint, Color figureColor)
{
type = figureType;
color = figureColor;
start = startPoint;
end = endPoint;
}
// Rect, Oval
public Figure(String figureType, int figureX, int figureY,
int figureWidth, int figureHeight, Color figureColor)
{
type = figureType;
x1 = figureX;
y1 = figureY;
width = figureWidth;
height = figureHeight;
color = figureColor;
}
// more shapes
}
public static void main(String args[])
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new JSPaint();
}
});
}
}
If the currently selected UI element shows up on the drawing area, this can have only one reason: you are doing something wrong with the Graphics objects, possibly calling a translate on them, and not resetting the tranlation when you are done. (See this link for an example of translate used correctly).

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