I want to have a text field to input an integer, then select 1) Grow or 2) Shrink, and then click the button so that the circle gets redrawn on the screen based on the selected options.
I don't know why it isn't repaining. (Don't worry about the layout, just want to get it to work first)
My Frame:
public class Main {
public static void main(String[] args) {
var frame = new JFrame();
frame.setSize(400,400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
var circleComp = new circleComponent();
var panel1 = new JPanel();
var multiplierLabel = new JLabel("Grow Multiplier");
var multiplierField = new JTextField(20);
var radio1 = new JRadioButton("Grow Circle");
var radio2 = new JRadioButton("Shrink Circle");
var bg = new ButtonGroup();
bg.add(radio1);
bg.add(radio2);
JButton button = new JButton("Rivizato");
button.addActionListener(
new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(radio1.isSelected()){
rrComp.repaint(0,0,Integer.parseInt(multiplierField.getText())*rrComp.getWidth(), Integer.parseInt(multiplierField.getText())*rrComp.getHeight());
}
else if(radio2.isSelected()){
rrComp.repaint(0,0,Integer.parseInt(multiplierField.getText())/rrComp.getWidth(), Integer.parseInt(multiplierField.getText())/rrComp.getHeight());
}
}
}
);
panel1.add(multiplierLabel);
panel1.add(multiplierField);
panel1.add(button);
panel1.add(radio1);
panel1.add(radio2);
frame.add(panel1);
frame.add(circleComp);
}
}
My CircleComponent class:
public class CircleComponent extends JComponent {
public void paintComponent(Graphics g){
super.paintComponent(g);
var g2 = (Graphics2D) g;
var circle = new Ellipse2D.Double(0,0,100,100);
g2.draw(circle);
}
}
var circle = new Ellipse2D.Double(0,0,100,100); means that your circle will never change size.
You should also be careful with repaint(x, y, width, height) as it could leave regions of your component "dirty". Better to just use repaint.
As a conceptual example...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
private CirclePane circlePane;
public MainPane() {
setLayout(new BorderLayout());
JPanel actionsPane = new JPanel(new GridBagLayout());
JButton growButton = new JButton("Grow");
growButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
circlePane.grow();
}
});
JButton shrinkButton = new JButton("Shrink");
shrinkButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
circlePane.shrink();
}
});
actionsPane.add(growButton);
actionsPane.add(shrinkButton);
circlePane = new CirclePane();
add(circlePane);
add(actionsPane, BorderLayout.SOUTH);
}
}
public class CirclePane extends JPanel {
private Ellipse2D circle;
public CirclePane() {
circle = new Ellipse2D.Double(0, 0, 100, 100);
}
public void grow() {
double width = circle.getWidth() + 10;
double height = circle.getHeight() + 10;
circle.setFrame(0, 0, width, height);
repaint();
}
public void shrink() {
double width = Math.max(0, circle.getWidth() - 10);
double height = Math.max(0, circle.getHeight() - 10);
circle.setFrame(0, 0, width, height);
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
double x = (getWidth() - circle.getWidth()) / 2d;
double y = (getHeight() - circle.getHeight()) / 2d;
g2d.translate(x, y);
g2d.draw(circle);
g2d.dispose();
}
}
}
nb: I know I've not used JTextField to specify the size of the circle, that's on purpose. You will need to adapt your requirements to work in a similar way - can you see where you might pass parameters to the CirclePane?
Related
I'm trying to animate a rectangle based on a coordinate determined by for-loop, inside a button. Here is my JComponent Class:
public class Rect extends JComponent {
public int x;
public int y;
public int w;
public int h;
public Rect (int x, int y, int w, int h) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
repaint();
}
#Override
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
super.paintComponent(g);
g2.setColor(Color.green);
g2.drawRect(x+15, y+15, w, h);
}
}
and here is my button and button inside JFrame class:
public class MainFrame extends JFrame {
Rect R = new Rect(15, 15, 50, 50);
JPanel lm = new JPanel();
LayoutManager lay = new OverlayLayout(lm);
JButton animate = new JButton("animate");
public MainFrame () {
setSize(1200, 700);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
lm.setLayout(lay);
lm.add(R);
}
animate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
for (int k = 0; k < 500; k+=50) {
R = new Rect(k, k, 50, 50);
validate();
repaint();
}
}
});
}
But when I run the code and click the button, nothing happens. What's wrong?
EDIT: I run the frame inside my main class like this:
public class OrImage {
public static void main(String[] args) throws Exception
SwingUtilities.invokeLater(new Runnable() {
public void run() {
MainFrame mf = new MainFrame();
mf.setVisible(true);
}
});
}
}
I changed the code of class MainFrame such that when you press the animate button, something happens, but I don't know if that is what you want to happen.
I did not change class Rect and I added main() method to MainFrame just to keep everything in one class.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.OverlayLayout;
public class MainFrame extends JFrame {
Rect R = new Rect(15, 15, 50, 50);
JPanel lm = new JPanel();
LayoutManager lay = new OverlayLayout(lm);
JButton animate = new JButton("animate");
public MainFrame () {
setSize(1200, 700);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
lm.setLayout(lay);
lm.add(R);
animate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
for (int k = 0; k < 500; k+=50) {
R = new Rect(k, k, 50, 50);
lm.add(R);
}
lm.revalidate();
lm.repaint();
}
});
add(lm, BorderLayout.CENTER);
add(animate, BorderLayout.PAGE_END);
setLocationByPlatform(true);
setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> new MainFrame());
}
}
The main change is in method actionPerformed(). You need to add R to the JPanel. You need to call revalidate() on the JPanel because you have changed the number of components that it contains. And after calling revalidate() you should call repaint() (again, on the JPanel) to make it redraw itself.
This is how it looks before pressing animate.
And this is how it looks after pressing animate
EDIT
As requested – with animation.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.OverlayLayout;
import javax.swing.Timer;
public class MainFrame extends JFrame {
Rect R = new Rect(15, 15, 50, 50);
JPanel lm = new JPanel();
LayoutManager lay = new OverlayLayout(lm);
JButton animate = new JButton("animate");
private int x;
private int y;
private Timer timer;
public MainFrame () {
setSize(1200, 700);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
lm.setLayout(lay);
lm.add(R);
timer = new Timer(500, event -> {
if (x < 500) {
lm.remove(R);
x += 50;
y += 50;
R = new Rect(x, y, 50, 50);
lm.add(R);
lm.revalidate();
lm.repaint();
}
else {
timer.stop();
}
});
timer.setInitialDelay(0);
animate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
timer.start();
}
});
add(lm, BorderLayout.CENTER);
add(animate, BorderLayout.PAGE_END);
setLocationByPlatform(true);
setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> new MainFrame());
}
}
JButtons are not displayed until or unless I hover on the buttons.
package paint;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
*
* #author Rehan Shakir
*/
public class PaintFrame extends JFrame implements MouseMotionListener,ActionListener
{
private int x=0;
private int y=0;
private final JButton red,yellow,blue,green;
private final JPanel p;
//private final JLabel l;
private final Container c;
private Color color;
public PaintFrame()
{
setTitle("Paint");
setSize(800,600);
setDefaultCloseOperation(EXIT_ON_CLOSE);
//setLayout(new FlowLayout());
p = new JPanel();
p.setLayout(new GridLayout(4,1));
red = new JButton("Red");
red.setBackground(Color.red);
p.add(red);
yellow = new JButton("Yellow");
yellow.setBackground(Color.yellow);
p.add(yellow);
blue = new JButton("Blue");
blue.setBackground(Color.blue);
p.add(blue);
green = new JButton("Green");
green.setBackground(Color.green);
p.add(green);
red.addActionListener(this);
yellow.addActionListener(this);
blue.addActionListener(this);
green.addActionListener(this);
c = this.getContentPane();
c.setLayout(new BorderLayout());
JLabel l = new JLabel("Drag the mouse to draw",JLabel.RIGHT);
c.add(l,BorderLayout.SOUTH);
c.add(p,BorderLayout.WEST);
c.addMouseMotionListener(this);
setVisible(true);
}
#Override
public void mouseDragged(MouseEvent e )
{
x= e.getX();
y= e.getY();
repaint();
}
#Override
public void mouseMoved(MouseEvent e)
{
}
#Override
public void actionPerformed(ActionEvent e)
{
String s = e.getActionCommand();
if(s.equals("Red"))
color = Color.red;
else if(s.equals("Yellow"))
color = Color.yellow;
else if(s.equals("Blue"))
color = Color.blue;
else if(s.equals("Green"))
color = Color.green;
else
color = Color.BLACK;
}
#Override
public void paint(Graphics g)
{
g.setColor(color);
g.fillOval(x, y, 4, 4);
}
}
Main Class
public class Paint {
package paint;
public static void main(String[] args) {
// TODO code application logic here
PaintFrame Jf = new PaintFrame();
}
}
When I execute this program only the first JButton is displayed on the screen. I have to hover on other buttons so that they can be displayed on the screen.
Why does this happen?
Immediately from your title, I could guess that you weren't calling the super's painting method in your override -- and I was right:
#Override
public void paint(Graphics g)
{
// ********** no super call here! *******
g.setColor(color);
g.fillOval(x, y, 4, 4);
}
By not doing this, you're not allowing the component to do its important house-keeping painting, including the painting of child components and removal of "dirty" pixels
This:
#Override
public void paint(Graphics g)
{
super.paint(g);
g.setColor(color);
g.fillOval(x, y, 4, 4);
}
will likely fix things
Having said this, I must add:
Don't paint directly in a JFrame
Do paint in the paintComponent method override of a class that extends JPanel instead
Call the super.paintComponent(g) in your JPanel's overridden method (for the same reasons).
Example using a BufferedImage:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
#SuppressWarnings("serial")
public class MainPaintPanel extends JPanel {
private PaintPanel paintPanel = new PaintPanel();
public MainPaintPanel() {
MyMouse myMouse = new MyMouse();
paintPanel.addMouseListener(myMouse);
paintPanel.addMouseMotionListener(myMouse);
JPanel btnPanel = new JPanel(new GridLayout(0, 1, 3, 3));
addColorButton(btnPanel, Color.RED, "Red");
addColorButton(btnPanel, Color.YELLOW, "Yellow");
addColorButton(btnPanel, Color.BLUE, "Blue");
addColorButton(btnPanel, Color.GREEN, "Green");
setLayout(new BorderLayout());
add(paintPanel, BorderLayout.CENTER);
add(btnPanel, BorderLayout.LINE_START);
}
class MyMouse extends MouseAdapter {
Point p1 = null;
private void moveOval(MouseEvent e) {
if (p1 == null) {
return;
}
Point p2 = e.getPoint();
paintPanel.addLine(p1, p2);
}
#Override
public void mousePressed(MouseEvent e) {
p1 = e.getPoint();
}
#Override
public void mouseDragged(MouseEvent e) {
moveOval(e);
p1 = e.getPoint();
}
#Override
public void mouseReleased(MouseEvent e) {
moveOval(e);
p1 = null;
}
}
private void addColorButton(JPanel btnPanel, Color color, String name) {
JButton button = new JButton(new ButtonAction(name, color));
button.setBackground(color);
btnPanel.add(button);
}
class ButtonAction extends AbstractAction {
private Color color;
public ButtonAction(String name, Color color) {
super(name);
this.color = color;
}
#Override
public void actionPerformed(ActionEvent e) {
paintPanel.setOvalColor(color);
}
}
private static void createAndShowGui() {
MainPaintPanel mainPanel = new MainPaintPanel();
JFrame frame = new JFrame("Painting GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
#SuppressWarnings("serial")
class PaintPanel extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 600;
private static final int OVAL_WIDTH = 4;
private static final Stroke BASIC_STROKE = new BasicStroke(OVAL_WIDTH);
private BufferedImage img;
private Color ovalColor;
public PaintPanel() {
img = new BufferedImage(PREF_W, PREF_W, BufferedImage.TYPE_INT_ARGB);
}
public void addLine(Point p1, Point p2) {
if (img != null && ovalColor != null) {
Graphics2D g2 = img.createGraphics();
g2.setStroke(BASIC_STROKE);
g2.setColor(ovalColor);
g2.drawLine(p1.x, p1.y, p2.x, p2.y);
g2.dispose();
repaint();
}
}
public void setOvalColor(Color ovalColor) {
this.ovalColor = ovalColor;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
}
I am practicing to draw a ball in the Panel and show the ball's coordinate when the ball is dragged.
This is my first time to practice a drawing exercise(?)
This is my code.
import java.awt.*;
import java.awt.event.*;
public class MovingBall extends Frame {
Panel ballPanel = new Panel();
Label ballLabel = new Label();
Panel coordinatePanel = new Panel();
Label coordinateLabel = new Label();
int x0=0,y0 =0, x=20,y=30;
int nowX, nowY;
Label nowXcoordinateLabel = new Label("Now X :"+nowX);
Label nowYcoordinateLabel = new Label("Now Y :"+nowY);
MovingBall(){
setLayout(new GridLayout(1,1));
ballPanel.add(ballLabel); coordinatePanel.add(coordinateLabel);
add(ballPanel);
add(coordinatePanel);
ballPanel.setBackground(Color.white);
coordinatePanel.setBackground(Color.LIGHT_GRAY);
nowXcoordinateLabel.setBackground(Color.WHITE);
nowYcoordinateLabel.setBackground(Color.WHITE);
coordinatePanel.add(nowXcoordinateLabel);
coordinatePanel.add(nowYcoordinateLabel);
setVisible(true);
setSize(400,400);
MouseMotionListener ml = new MouseMotionAdapter(){
public void mouseDragged(MouseEvent e){
Point p = new Point();
nowX = (int) p.getX();
nowY = (int) p.getY();
}
};
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
dispose();
}
}
);
}
public void paintComponent(Graphics2D gg){
// super.paintComponents(gg);
ballPanel.paintComponents(gg);
gg.setColor(Color.BLUE);
gg.fillOval(x0, y0, 10, 10);
}
public static void main(String[]arg){
MovingBall mb = new MovingBall();
}
}
I have two problems
I used fillOval and paintComponent to draw and display a ball but I don't see that on the screen. Why?
Any idea how to move the ball if I want to move that using mouseDragged? Do I need some thread?
Let's start with
Frame doesn't have a paintComponent method, so nothing is ever going to call it.
Even if it did, position 0x0 would paint the circle under the frame's borders, so you wouldn't see it
You should be getting the Point from the MouseEvent, not from the new Point object you've created
It's not the responsibility of the frame to manage the mouse dragged or painting, the frame is responsible for providing the initial container onto which everything else added
From that, you should move the functionality of the painting and mouse dragged management to it's own class. This provides you with two things, first, a surface onto which you can paint, and which will contained within the frame borders and the mouse events will automatically be converted to the panels context (0x0 will be the top left corner of the panel)
This raises the question about how to update the labels. Well, you could take a leaf from the AWT API and use a simple observer pattern to generate events when the coordinates are changed, for example
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Label;
import java.awt.Panel;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.EventObject;
import java.util.List;
public class MovingBall extends Frame {
BallPane ballPanel = new BallPane();
Label ballLabel = new Label();
int x0 = 0, y0 = 0, x = 20, y = 30;
int nowX, nowY;
Label nowXcoordinateLabel = new Label("Now X :" + nowX);
Label nowYcoordinateLabel = new Label("Now Y :" + nowY);
MovingBall() {
setLayout(new BorderLayout());
ballPanel.add(ballLabel);
add(ballPanel);
ballPanel.setBackground(Color.white);
nowXcoordinateLabel.setBackground(Color.WHITE);
nowYcoordinateLabel.setBackground(Color.WHITE);
setVisible(true);
setSize(400, 400);
addWindowListener(new WindowAdapter() {
#Override
public void windowClosed(WindowEvent e) {
dispose();
}
});
Panel coordinates = new Panel(new FlowLayout());
coordinates.add(nowXcoordinateLabel);
coordinates.add(nowYcoordinateLabel);
coordinates.setBackground(Color.LIGHT_GRAY);
add(coordinates, BorderLayout.SOUTH);
ballPanel.addCoordinateListene(new CoordinateListener() {
#Override
public void coordinatesChanged(CoordinateEvent evt) {
nowXcoordinateLabel.setText("Now X: " + evt.getCoordinate().getX());
nowYcoordinateLabel.setText("Now X: " + evt.getCoordinate().getY());
revalidate();
repaint();
}
});
}
public static void main(String[] arg) {
MovingBall mb = new MovingBall();
}
public class CoordinateEvent extends EventObject {
private final Point p;
public CoordinateEvent(Object source, Point p) {
super(source);
this.p = p;
}
public Point getCoordinate() {
return p;
}
}
public interface CoordinateListener {
public void coordinatesChanged(CoordinateEvent evt);
}
public class BallPane extends Panel {
int x0 = 0, y0 = 0, x = 20, y = 30;
private List<CoordinateListener> coordinateListeners;
public BallPane() {
MouseMotionListener ml = new MouseMotionAdapter() {
public void mouseDragged(MouseEvent e) {
x0 = (int) e.getX();
y0 = (int) e.getY();
fireCoordinateChange(new Point(e.getPoint()));
repaint();
}
};
addMouseMotionListener(ml);
coordinateListeners = new ArrayList<>(5);
}
#Override
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.BLUE);
g.fillOval(x0, y0, 10, 10);
}
public void addCoordinateListene(CoordinateListener listener) {
coordinateListeners.add(listener);
}
public void removeCoordinateListene(CoordinateListener listener) {
coordinateListeners.remove(listener);
}
protected void fireCoordinateChange(Point p) {
CoordinateEvent evt = new CoordinateEvent(this, p);
for (CoordinateListener listener : coordinateListeners) {
listener.coordinatesChanged(evt);
}
}
}
}
Make your class extending Panel and make it ready to drawing with overriding paint method and add the MouseMotionListener to listining your panel.Get X and Y coordinates for using in paint method, at last add your drawing panel to Frame.
Simple code : UPDATED
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.Panel;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class TestClass extends Panel {
/**
*
*/
private static final long serialVersionUID = 1L;
Panel ballPanel = new Panel();
Label ballLabel = new Label();
Panel coordinatePanel = new Panel();
Label coordinateLabel = new Label();
int nowX, nowY;
Label nowXcoordinateLabel = new Label("Now X :");
Label nowYcoordinateLabel = new Label("Now Y :");
TestClass() {
coordinatePanel.add(coordinateLabel);
nowXcoordinateLabel.setBackground(Color.WHITE);
nowYcoordinateLabel.setBackground(Color.WHITE);
nowXcoordinateLabel.setPreferredSize(new Dimension(100, 25));
nowYcoordinateLabel.setPreferredSize(new Dimension(100, 25));
coordinatePanel.setPreferredSize(new Dimension(400, 30));
coordinatePanel.setBackground(Color.LIGHT_GRAY);
coordinatePanel.add(nowXcoordinateLabel);
coordinatePanel.add(nowYcoordinateLabel);
MouseAdapter ml = new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent e) {
nowXcoordinateLabel.setText("Now X :" + e.getX());
nowYcoordinateLabel.setText("Now Y :" + e.getY());
nowX = e.getX();
nowY = e.getY();
repaint();
super.mouseMoved(e);
}
};
setLayout(new GridLayout(1, 1));
setBackground(Color.WHITE);
addMouseMotionListener(ml);
setVisible(true);
setSize(400, 400);
}
#Override
public void paint(Graphics g) {
Graphics2D gg = (Graphics2D) g;
gg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
gg.setColor(Color.BLUE);
gg.fillOval(nowX, nowY, 20, 20);
}
public static void main(String[] arg) {
TestClass mb = new TestClass();
Frame frame = new Frame("Test drawing");
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
frame.dispose();
super.windowClosing(e);
}
});
frame.setLayout(new GridLayout(1, 1));
frame.add(mb);
frame.add(mb.coordinatePanel);
frame.setSize(800, 600);
frame.setVisible(true);
}
}
To get the position of the mouse instead of:
nowX = (int) p.getX();
Write this:
nowX = (int) e.getX();
You also need to redraw the oval every time the user triggers a Mouse Drag event
This is my main class:
public class Sad {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Sad window = new Sad();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Sad() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 512, 399);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new CardLayout(0, 0));
JPanel panel = new JPanel();
frame.getContentPane().add(panel, "name_12361565901507");
panel.setLayout(null);
JButton btnNes = new JButton("Nes");
btnNes.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
Grafik grafik = new Grafik(20, 20, 100);
panel.add(grafik);
}
});
btnNes.setBounds(90, 146, 89, 23);
panel.add(btnNes);
}
}
And this is drawing class
public class Grafik extends JPanel{
private int x;
private int y;
private int r;
public Grafik(int x, int y, int r){
this.x = x;
this.y = y;
this.r = r;
}
public void paintComponent(Graphics g) {
Graphics2D g2 =(Graphics2D) g;
Ellipse2D circ = new Ellipse2D.Float(x, y, r, r);
g2.setColor(Color.RED);
g2.draw(circ);
}
}
They are in same package. And when i click button its suposed to draw Ellipse in red color, but it doesn't show anything. Can someone help me? BTW Sorry for bad english
It's because you don't call panel.setBounds(), revalidate() and repaint().
But you shouldn't use a null layout anyway: Use layout
managers.
You should call super.paintComponent(g) at the beginning of
the paintComponent method.
Rather than adding a new component to the panel after every button press you might want to just toggle a boolean value inside the Grafik instance which determines wheter the ellipse should be visible or not.
If you want the ellipse to be "smooth", you can call g2.setRenderingHint(hintKey, hintValue).
Modified code including my suggestions:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Sad {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Sad window = new Sad();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Sad() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 512, 399);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Grafik grafik = new Grafik(20, 20, 100);
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.add(grafik);
JButton btnNes = new JButton("Nes");
btnNes.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
grafik.setEllipseVisible(true);
panel.repaint();
}
});
JPanel btnPanel = new JPanel();
btnPanel.add(btnNes);
panel.add(btnPanel, BorderLayout.SOUTH);
frame.setContentPane(panel);
}
}
class Grafik extends JPanel {
private int x;
private int y;
private int r;
private boolean ellipseVisible;
public Grafik(int x, int y, int r) {
this.x = x;
this.y = y;
this.r = r;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (isEllipseVisible()) {
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Ellipse2D circ = new Ellipse2D.Float(x, y, r, r);
g2.setColor(Color.RED);
g2.draw(circ);
}
}
public boolean isEllipseVisible() {
return ellipseVisible;
}
public void setEllipseVisible(boolean ellipseVisible) {
this.ellipseVisible = ellipseVisible;
}
}
I am unable to draw line when I press the component in Java Swing. How can I do this? I already used paint method, my problem is when program executes paint method invoke automatically, DrawLine() method will be there in paint method, so is there any way that I can get the lines other than paint method?
Please give some suggestion.
Below code I have tried, it's displaying lines but I want to display the lines when I click the component.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
public class ReferenceLink1 extends JFrame
{
JLabel l1;
JLabel l2;
JPanel p1;
ReferenceLink1()
{
p1 = new JPanel();
p1.setLayout(null);
p1.setBackground(Color.ORANGE);
p1.setOpaque(true);
p1.setBounds(0,0,300,400);
setLayout(null);
l1 = new JLabel();
l1.setText("l1");
l1.setBounds(20, 40, 100, 40);
l1.setHorizontalAlignment(SwingConstants.CENTER);
l1.setBackground(Color.GREEN);
l1.setOpaque(true);
l2 = new JLabel(); ;
l2.setText("l2");
l2.setBounds(20, 100,100,40);
l2.setBackground(Color.BLUE);
l2.setHorizontalAlignment(SwingConstants.CENTER);
l2.setOpaque(true);
p1.add(l1);
p1.add(l2);
add(p1);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setBounds(0,0,400,400);
}
public void paint(Graphics g)
{
super.paint(g);
g.drawLine(77,110,77,130);
}
public static void main(String args[])
{
ReferenceLink1 rf = new ReferenceLink1();
}
}
class Surface extends JPanel {
private void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.blue);
Dimension size = getSize();
Insets insets = getInsets();
int w = size.width - insets.left - insets.right;
int h = size.height - insets.top - insets.bottom;
Random r = new Random();
for (int i = 0; i < 1000; i++) {
int x = Math.abs(r.nextInt()) % w;
int y = Math.abs(r.nextInt()) % h;
g2d.drawLine(x, y, x, y);
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class Points extends JFrame {
public Points() {
initUI();
}
private void initUI() {
setTitle("Points");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(new Surface());
setSize(350, 250);
setLocationRelativeTo(null);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Points ps = new Points();
ps.setVisible(true);
}
});
}
}
You could simply add a mouse listener to the label that represents your button.
l2.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
p1.getGraphics().drawLine(77,110,77,130);
}
});
public class ReferenceLink1 extends JFrame {
JLabel l1;
JButton l2;
JPanel p1;
public static class MyListener implements ActionListener{
Graphics g;
public MyListener(Graphics g) {
this.g = g;
}
#Override
public void actionPerformed(ActionEvent e) {
g.drawLine(77, 110, 77, 130);
}
}
public ReferenceLink1() {
p1 = new JPanel();
setVisible(true);
p1.setLayout(null);
p1.setBackground(Color.ORANGE);
p1.setOpaque(true);
p1.setBounds(0,0,300,400);
setLayout(null);
l1 = new JLabel();
l1.setText("l1");
l1.setBounds(20, 40, 100, 40);
l1.setHorizontalAlignment(SwingConstants.CENTER);
l1.setBackground(Color.GREEN);
l1.setOpaque(true);
l2 = new JButton();
l2.addActionListener(new MyListener(this.getGraphics()));
l2.setText("l2");
l2.setBounds(20, 100,100,40);
l2.setBackground(Color.BLUE);
l2.setHorizontalAlignment(SwingConstants.CENTER);
l2.setOpaque(true);
p1.add(l1);
p1.add(l2);
add(p1);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(0,0,400,400);
}
public static void main(String args[]) {
ReferenceLink1 rf = new ReferenceLink1();
}
}