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Painting method paints things from other components

I am trying to make a simple Java program with GUI using Java Swing.
I have painting panel (gPanel) in the center of the screen, panel with buttons (buttonSet) in the west and panel with labels (labelPanel) in the east. To paint over gPanel I use paintComponent method and since I have two buttons, which are supposed to draw different things (and change label on the right of the screen), I decided to put switch case in paintComponent method for it to choose the correct actual painting method.
When I run the program everything looks fine - program uses the first method to paint and there is a sampletext.png image shown in the middle of the screen with yellow background, as it should be. Button number 1 also uses this method to draw over gPanel, so pressing it draws the same thing.
Now Button number 2 uses the second painting method and this is where things go wrong. It draws sampleimage.png over the gPanel, but also parts of left and right panels (i.e. buttons from left buttonSet panel and orange colour that is background colour of side panels) are drawn, though it shouldn't happen. Also the whole gPanel becomes gray (I think it happens because of label on the right that becomes very long after pressing Button number 2, because when the label was shorter gPanel didn't turn gray and left the previously drawn things instead).
Pressing Button number 1 paints things from first method properly, so pressing it after pressing Button number 2 "reverts" the changes.
What do I have to do to make my second painting method work properly?
Also why adding border to buttonSet and labelPanel works but adding it to gPanel doesn't?
package com.inferjus.drawingproject;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.border.*;
/**
*
* #author inferjus
*/
public class DrawingProject
{
private JFrame frame;
private graphicPanel gPanel;
private JPanel buttonSet;
private JPanel labelPanel;
private JLabel label;
private int painter=0;
public static void main(String[] args)
{
DrawingProject program=new DrawingProject();
program.prepareGUI();
}
public int getPainter()
{
return painter;
}
public void setPainter(int x)
{
painter=x;
}
public void prepareGUI()
{
//setting JFrame and icon
frame=new JFrame("Drawing Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
try { frame.setIconImage(ImageIO.read(getClass().getResource("/resources/sampleicon.png")));}
catch (IOException e) { e.printStackTrace(); }
//border for components
Border bigBlackBorder=new LineBorder(Color.black, 3);
//setting JPanel (graphicPanel) for drawing images
gPanel=new graphicPanel();
gPanel.setBorder(bigBlackBorder); // <--- why it does not work?
//setting JPanel for buttons on the left of the screen
buttonSet=new JPanel();
buttonSet.setLayout(new BoxLayout(buttonSet, BoxLayout.Y_AXIS));
buttonSet.setBorder(bigBlackBorder);
//setting JButtons
JButton buttonOne=new JButton("Button number 1");
buttonOne.addActionListener(new buttonOneListener());
buttonSet.add(buttonOne);
buttonSet.setBackground(Color.orange);
JButton buttonTwo=new JButton("Button number 2");
buttonTwo.addActionListener(new buttonTwoListener());
buttonSet.add(buttonTwo);
//setting JLabels on the right of the screen
label=new JLabel("Default label");
label.setFont(new Font("Consolas", Font.PLAIN, 20));
labelPanel=new JPanel();
labelPanel.setLayout(new BoxLayout(labelPanel, BoxLayout.Y_AXIS));
labelPanel.setBackground(Color.orange);
labelPanel.setBorder(bigBlackBorder);
JLabel popeLabelTitle=new JLabel("What does the label say?");
popeLabelTitle.setFont(new Font("Consolas", Font.BOLD, 24));
//adding JLabels to labelPanel
labelPanel.add(BorderLayout.NORTH, popeLabelTitle);
labelPanel.add(BorderLayout.CENTER, label);
//adding components to JFrame
frame.getContentPane().add(BorderLayout.CENTER, gPanel);
frame.getContentPane().add(BorderLayout.EAST, labelPanel);
frame.getContentPane().add(BorderLayout.WEST, buttonSet);
frame.setVisible(true);
}
class graphicPanel extends JPanel
{
private BufferedImage sampletext=null;
private BufferedImage sampleimage=null;
#Override
public void paintComponent(Graphics g)
{
//for Button One paint sampletext.png, for Button Two paint sampleimage.png
switch (painter)
{
case 0:
paintSampletext(g);
break;
case 1:
paintSampleimage(g);
break;
}
}
//paint yellow background and put sampletext.png in the middle
private void paintSampletext(Graphics g)
{
if (sampletext==null)
{
gPanel.setSampletextPNG();
}
g.setColor(Color.yellow);
g.fillRect(0,0, gPanel.getWidth(), gPanel.getHeight());
g.drawImage(sampletext, gPanel.getWidth()/2-sampletext.getWidth()/2, gPanel.getHeight()/2-sampletext.getHeight()/2, this);
g.setColor(Color.black);
g.drawRect(gPanel.getWidth()/2-sampletext.getWidth()/2, gPanel.getHeight()/2-sampletext.getHeight()/2, sampletext.getWidth(), sampletext.getHeight());
g.dispose();
}
//paint sampleimage.png over what is already displayed
private void paintSampleimage(Graphics g)
{
if (sampleimage==null)
{
gPanel.setSampleimagePNG();
}
int x=(int)((Math.random()*gPanel.getWidth())-sampleimage.getWidth());
int y=(int)((Math.random()*gPanel.getHeight())-sampleimage.getHeight());
g.drawImage(sampleimage, x, y, gPanel);
g.dispose();
}
public void setSampletextPNG()
{
try { sampletext=ImageIO.read(getClass().getResource("/resources/sampletext.png")); }
catch (IOException ex) { System.out.println("Image error"); }
}
public void setSampleimagePNG()
{
try { sampleimage=ImageIO.read(getClass().getResource("/resources/sampleimage.png")); }
catch (IOException ex) { System.out.println("Image error"); }
}
}
class buttonOneListener implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
label.setText("Reaction to button number 1: change of label.");
setPainter(0);
gPanel.repaint();
}
}
class buttonTwoListener implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
label.setText("Reaction to button number 2: change of label + drawing images over gPanel.");
setPainter(1);
gPanel.repaint();
}
}
}
Tree of my project:
DrawingProject
-JRE System Library
-src
--com.inferjus.drawingproject
---DrawingProject.java
--resources
---sampleicon.png
---sampleimage.png
---sampletext.png
what shows after running the program by default or after pressing Button One
what shows after pressing Button Two one time
what shows after pressing Button Two a few times

Introduction
Oracle has a helpful tutorial, Creating a GUI With Swing. Skip the Learning Swing with the NetBeans IDE section.
I went ahead and created the following GUI. I created two BufferedImages for the text image and the plain image so I wouldn't have to read any external files.
Explanation
When I create a Swing GUI, I use the model-view-controller pattern. This pattern allows me to separate my concerns and focus on one part of the application at a time.
Model
I created a model class to hold the button flag and the two BufferedImages. This is the class where you would read the resources.
You can add the JFrame icon back to this class.
Model classes are plain Java getter/setter classes.
View
All Swing applications must start with a call to the SwingUtilities invokeLater method. This method ensures that the Swing components are created and executed on the Event Dispatch Thread.
Class names are written in camel case and start with an upper case character. Method names are written in camel case and start with a lower case character. Field names follow the same rules as method names.
I separated the creation of the JFrame from the creation of the JPanels. This helps me to separate my concerns and makes it much easier to visually verify whether or not the code is correct. Aim to write short methods that do one thing and do it well.
You have to manually draw a border on a graphic JPanel. I added the code to your paintComponent method to paint a partial border.
Your paintComponent method should paint. Period. Nothing else. It must also start with a call to the super.paintComponent method to maintain the Swing paint chain.
I changed your JLabel in the right JPanel to a JTextArea. A JTextArea allows for longer messages to word wrap on multiple lines and not make your JFrame change size.
Controller
Your JButton controller classes were fine, except for the class names.
Code
Here's the complete runnable code. I made all the additional classes inner classes so I could post the code in one block.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class DrawingProject implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new DrawingProject());
}
private final DrawingModel model;
private GraphicPanel graphicPanel;
private JTextArea textArea;
public DrawingProject() {
this.model = new DrawingModel();
}
#Override
public void run() {
JFrame frame = new JFrame("Drawing Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
graphicPanel = new GraphicPanel(model);
frame.add(createButtonPanel(), BorderLayout.WEST);
frame.add(graphicPanel, BorderLayout.CENTER);
frame.add(createTextPanel(), BorderLayout.EAST);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtonPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setBackground(Color.orange);
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JButton buttonOne = new JButton("Button number 1");
buttonOne.addActionListener(new ButtonOneListener());
panel.add(buttonOne);
JButton buttonTwo = new JButton("Button number 2");
buttonTwo.addActionListener(new ButtonTwoListener());
panel.add(buttonTwo);
return panel;
}
private JPanel createTextPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JLabel popeLabelTitle = new JLabel("What does the label say?");
popeLabelTitle.setFont(new Font(Font.MONOSPACED, Font.BOLD, 24));
panel.add(popeLabelTitle, BorderLayout.NORTH);
textArea = new JTextArea(4, 30);
textArea.setEditable(false);
textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 20));
textArea.setText("Default label");
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
panel.add(textArea, BorderLayout.CENTER);
return panel;
}
public class GraphicPanel extends JPanel {
private static final long serialVersionUID = 1L;
private final DrawingModel model;
public GraphicPanel(DrawingModel model) {
this.model = model;
this.setPreferredSize(new Dimension(640, 480));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Paint border
int width = getWidth();
int height = getHeight();
int lineThickness = 3;
g.setColor(Color.BLACK);
g.fillRect(0, 0, width, height);
g.setColor(Color.YELLOW);
g.fillRect(0, lineThickness, width, height - 2 * lineThickness);
switch (model.getPainter()) {
case 0:
paintSampleText(g);
break;
case 1:
paintSampleImage(g);
break;
}
}
private void paintSampleText(Graphics g) {
BufferedImage image = model.getSampleText();
int x = (getWidth() - image.getWidth()) / 2;
int y = (getHeight() - image.getHeight()) / 2;
g.drawImage(image, x, y, this);
}
private void paintSampleImage(Graphics g) {
BufferedImage image = model.getSampleImage();
int x = (int) ((Math.random() * getWidth()) - image.getWidth());
int y = (int) ((Math.random() * getHeight()) - image.getHeight());
g.drawImage(image, x, y, this);
}
}
public class ButtonOneListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 1: change of label.");
model.setPainter(0);
graphicPanel.repaint();
}
}
public class ButtonTwoListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 2: change of label + "
+ "drawing images over gPanel.");
model.setPainter(1);
graphicPanel.repaint();
}
}
public class DrawingModel {
private int painter;
private final BufferedImage sampleText;
private final BufferedImage sampleImage;
public DrawingModel() {
this.painter = 0;
this.sampleText = createBufferedImage(Color.BLUE);
this.sampleImage = createBufferedImage(Color.MAGENTA);
}
private BufferedImage createBufferedImage(Color color) {
BufferedImage image = new BufferedImage(64, 64,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(color);
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.dispose();
return image;
}
public int getPainter() {
return painter;
}
public void setPainter(int painter) {
this.painter = painter;
}
public BufferedImage getSampleText() {
return sampleText;
}
public BufferedImage getSampleImage() {
return sampleImage;
}
}
}
Update
In order to paint multiple images, you have to save the origin of the images in a List. I've modified the application model to hold a List of origin Point instances. I also corrected the code to create a random point.
Here's the GUI with multiple images.
Here's the modified code
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class DrawingProject implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new DrawingProject());
}
private final DrawingModel model;
private GraphicPanel graphicPanel;
private JTextArea textArea;
public DrawingProject() {
this.model = new DrawingModel();
}
#Override
public void run() {
JFrame frame = new JFrame("Drawing Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
graphicPanel = new GraphicPanel(model);
frame.add(createButtonPanel(), BorderLayout.WEST);
frame.add(graphicPanel, BorderLayout.CENTER);
frame.add(createTextPanel(), BorderLayout.EAST);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtonPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setBackground(Color.orange);
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JButton buttonOne = new JButton("Button number 1");
buttonOne.addActionListener(new ButtonOneListener());
panel.add(buttonOne);
JButton buttonTwo = new JButton("Button number 2");
buttonTwo.addActionListener(new ButtonTwoListener());
panel.add(buttonTwo);
return panel;
}
private JPanel createTextPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 3));
JLabel popeLabelTitle = new JLabel("What does the label say?");
popeLabelTitle.setFont(new Font(Font.MONOSPACED, Font.BOLD, 24));
panel.add(popeLabelTitle, BorderLayout.NORTH);
textArea = new JTextArea(4, 30);
textArea.setEditable(false);
textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 20));
textArea.setText("Default label");
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
panel.add(textArea, BorderLayout.CENTER);
return panel;
}
public class GraphicPanel extends JPanel {
private static final long serialVersionUID = 1L;
private final DrawingModel model;
public GraphicPanel(DrawingModel model) {
this.model = model;
this.setPreferredSize(new Dimension(640, 480));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
paintMyBorder(g);
if (model.getPainter() == 1) {
createSampleImage(g);
}
paintSampleText(g);
BufferedImage image = model.getSampleImage();
List<Point> origin = model.getImageOrigin();
for (Point point : origin) {
g.drawImage(image, point.x, point.y, this);
}
}
private void paintMyBorder(Graphics g) {
int width = getWidth();
int height = getHeight();
int lineThickness = 3;
g.setColor(Color.BLACK);
g.fillRect(0, 0, width, height);
g.setColor(Color.YELLOW);
g.fillRect(0, lineThickness, width, height - 2 * lineThickness);
}
private void paintSampleText(Graphics g) {
BufferedImage image = model.getSampleText();
int x = (getWidth() - image.getWidth()) / 2;
int y = (getHeight() - image.getHeight()) / 2;
g.drawImage(image, x, y, this);
}
private void createSampleImage(Graphics g) {
BufferedImage image = model.getSampleImage();
int x = (int) (Math.random() * (getWidth() - image.getWidth()));
int y = (int) (Math.random() * (getHeight() - image.getHeight()));
model.addNewImageOrigin(new Point(x, y));
}
}
public class ButtonOneListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 1: change of label.");
model.setPainter(0);
graphicPanel.repaint();
}
}
public class ButtonTwoListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
textArea.setText("Reaction to button number 2: change of label + "
+ "drawing images over gPanel.");
model.setPainter(1);
graphicPanel.repaint();
}
}
public class DrawingModel {
private int painter;
private final BufferedImage sampleText;
private final BufferedImage sampleImage;
private final List<Point> imageOrigin;
public DrawingModel() {
this.painter = 0;
this.sampleText = createBufferedImage(Color.BLUE);
this.sampleImage = createBufferedImage(Color.MAGENTA);
this.imageOrigin = new ArrayList<>();
}
private BufferedImage createBufferedImage(Color color) {
BufferedImage image = new BufferedImage(64, 64,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(color);
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.dispose();
return image;
}
public void addNewImageOrigin(Point point) {
this.imageOrigin.add(point);
}
public int getPainter() {
return painter;
}
public void setPainter(int painter) {
this.painter = painter;
}
public BufferedImage getSampleText() {
return sampleText;
}
public BufferedImage getSampleImage() {
return sampleImage;
}
public List<Point> getImageOrigin() {
return imageOrigin;
}
}
}

why repeated call to repaint() method did not work

My objective is to put a button and a circle on the JFrame. When i click the button the circle should move randomly on the panel/frame.
But when i click the button the circle just move once only and after putting SOP statements i found that "frame.repaint()" is getting called multiple times but this call is triggering the "paintComponent" method only once, the very first time (defined in class Panel1). Its very strange!
I have also provided another code which works as expected but has no buttons to trigger the animation. I have read that repaint() requests are coalesced together and executed once, then how come the second program works?
import java.awt.event.*;
import java.awt.Graphics.*;
import javax.swing.*;
import java.awt.*;
public class SimpleGui3c_4 {
public static void main(String args[]) {
Frame1 frame = new Frame1();
frame.go();
}
}
class Frame1 {
JFrame frame;
Panel1 p;
void go() {
frame = new JFrame();
JButton button1 = new JButton("Color Change");
p = new Panel1();
frame.setSize(500,500);
frame.setVisible(true);
frame.getContentPane().add(BorderLayout.SOUTH, button1);
frame.getContentPane().add(BorderLayout.CENTER, p);
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
button1.addActionListener(new ColorActionListener());
}
class ColorActionListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
for(int i=0;i<130;i++) {
System.out.println("Frame repaint started");
frame.repaint();
try {
Thread.sleep(5000);
}catch(Exception ex) {}
System.out.println("Frame repaint ended");
}
}
}
class Panel1 extends JPanel {
public void paintComponent(Graphics g) {
System.out.println("Inside the paint Component method");
int x = (int)(Math.random()*100);
int y = (int)(Math.random()*100);
g.setColor(Color.BLUE);
g.fillOval(x,y,100,100);
System.out.println("Exiting the paint component method");
}
}
}
Code which works but has no button to trigger the animation, it works as soon as i run the code. I am not sure why the below program works and the above program fails!
import javax.swing.*;
import java.awt.*;
public class SimpleAnimation {
int x = 70;
int y = 70;
public static void main(String args[]) {
SimpleAnimation gui = new SimpleAnimation();
gui.go();
}
public void go() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyDrawPanel drawPanel = new MyDrawPanel();
frame.getContentPane().add(drawPanel);
frame.setSize(300,300);
frame.setVisible(true);
for(int i = 0;i<130;i++) {
//x++;
//y++;
drawPanel.repaint();
try {
Thread.sleep(50);
}catch(Exception ex) {}
}
}//close go
class MyDrawPanel extends JPanel {
public void paintComponent(Graphics g) {
g.setColor(Color.WHITE);
g.fillRect(0,0,this.getWidth(), this.getHeight());
int x = (int)(Math.random()*70);
int y = (int)(Math.random()*70);
g.setColor(Color.green);
g.fillOval(x,y,40,40);
}
}
}

I have also provided another code which works as expected but has no buttons to trigger the animation.
The difference between the two pieces of code is context within which they are been called.
The code that "works" is actually been updated out side the context of the Even Dispatching Thread, in the "main" thread, which means that doing something like Thread.sleep won't prevent the UI from been updated.
The code which does not work is been updated from with the content of the Event Dispatching Thread (from within the ActionListener), which is prevent the EDT from processing new paint requests until after the actionPerformed method returns
Another issue you will face relates to when you decide to update the position of the circle.
paintComponent can be called for all a number of different reasons, many which you don't control. Painting should focus on painting the current state and should never modify it (directly or indirectly). Instead, you should use some kind of update method, whose job it is, is to update the x/y position of the circle and trigger a new paint cycle.
I would highly recommend that you stop and take the time to read through:
Concurrency in Swing for a more detail explanation
How to use Swing Timers for a possible solution
Performing Custom Painting and Painting in AWT and Swing for a better understanding into how painting actually works in Swing.
Your problem is rookie mistake which comes about from not understanding how the API actually works and not understanding the tools available to solve it
There are a number of other "issues" which would result in undesirable behaviour, like not calling setVisible last, so the UI doesn't need be updated again to ensure that the components been added are visible.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
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.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class SimpleGui3c_4 {
public static void main(String args[]) {
new SimpleGui3c_4();
}
public SimpleGui3c_4() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
Frame1 frame = new Frame1();
frame.go();
}
});
}
public interface Animatable {
public void update();
}
public class Frame1 {
JFrame frame;
Panel1 p;
void go() {
frame = new JFrame();
JButton button1 = new JButton("Color Change");
p = new Panel1();
frame.getContentPane().add(BorderLayout.SOUTH, button1);
frame.getContentPane().add(BorderLayout.CENTER, p);
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
button1.addActionListener(new ColorActionListener(p));
frame.pack();
frame.setVisible(true);
}
class ColorActionListener implements ActionListener {
private Animatable parent;
public ColorActionListener(Animatable parent) {
this.parent = parent;
}
public void actionPerformed(ActionEvent e) {
JButton btn = (JButton) e.getSource();
btn.setEnabled(false);
Timer timer = new Timer(5000, new ActionListener() {
private int counter = 0;
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Frame repaint started");
parent.update();
counter++;
if (counter >= 130) {
((Timer)e.getSource()).stop();
btn.setEnabled(true);
}
}
});
timer.setInitialDelay(0);
timer.start();
}
}
class Panel1 extends JPanel implements Animatable {
private int xPos, yPos;
public Panel1() {
update();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
System.out.println("Inside the paint component method");
g.setColor(Color.BLUE);
g.fillOval(xPos, yPos, 100, 100);
System.out.println("Exiting the paint component method");
}
#Override
public void update() {
System.out.println("Inside the update method");
xPos = (int) (Math.random() * 100);
yPos = (int) (Math.random() * 100);
repaint();
}
}
}
}

Painting inside Swing Timer not working

I never worked with Timers before so my problem is probably stupid one really. My program draws a circle which is red and after random seconds the circle should change its color to green. I just made a swing timer as you can see below in the code. And it enters actionPerformed() method but it doesn't change color. Could you help me somehow fix my problem with changing colors?
My code:
package igrica;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class ChangingCircle implements ActionListener{
JFrame frame;
Timer timer;
Random r;
public static void main(String[] args) {
ChangingCircle gui = new ChangingCircle();
gui.go();
}
public void go() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyPanel panel = new MyPanel();
frame.getContentPane().add(BorderLayout.CENTER, panel);
frame.setSize(300, 300);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent event) {
frame.repaint();
}
class MyPanel extends JPanel {
public void paintComponent(Graphics g) {
g.setColor(Color.red);
g.fillOval(100, 100, 100, 100);
Random r = new Random();
Timer timer = new Timer(r.nextInt(5000) + 1000, new ActionListener() {
public void actionPerformed(ActionEvent ev) {
System.out.println("Timer out");
g.setColor(Color.green);
g.fillOval(100, 100, 100, 100);
}
});
timer.start();
}
}
}

There's quite the mess in your code. Try this:
public class ChangingCircle {
Color color = Color.RED;
MyPanel panel = new MyPanel();
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
ChangingCircle gui = new ChangingCircle();
gui.go();
});
}
public void go() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(panel, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
Random r = new Random();
Timer timer = new Timer(r.nextInt(5000) + 1000, new ActionListener() {
public void actionPerformed(ActionEvent ev) {
System.out.println("Timer");
color = Color.GREEN;
panel.repaint();
}
});
timer.setRepeats(false);
timer.start();
}
class MyPanel extends JPanel {
private int size = 100, loc = 100;
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(color);
g.fillOval(loc, loc, size, size);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(size + loc, size + loc);
}
}
}
The idea is that the timer only changes the property of the shape to be drawn and then calls repaint() to reflect the change. The paintComponent is called whenever it is needed, even in quick succession and should return quickly.
Specific Notes:
Start Swing from the EDT.
Create and start the timer from outside of paintComponent since it is called many times and that will create and start many timers.
You should probably set the timer not to repeat.
Call super.paintComponent(g); as the first thing inside paintComponent.
You seem to have an ActionListener that does nothing.
General tips:
Use the #Override annotation when applicable.
Call pack() on the frame instead of setting its size manually and #Override the getPreferredSize method of the component you paint on. Return a meaningful size based on what you draw.
Use add(component, location) and not the other way around (deprecated).
Don't use fields when local variables will do (Random r for example).
Use uppercase constant names (Color.RED instead of Color.red).

Don't initiate a Timer from within a paintComponent method. This method should be for painting and painting only. Instead start the Timer in your constructor and within your Timer's actionPerromed and call repaint(), change the state of a field of the class, and use that information within the paintComponent use that field to draw any new information.
e.g.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class ChangingCircle {
JFrame frame;
public static void main(String[] args) {
ChangingCircle gui = new ChangingCircle();
gui.go();
}
public void go() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyPanel panel = new MyPanel();
frame.getContentPane().add(BorderLayout.CENTER, panel);
frame.setSize(300, 300);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent event) {
frame.repaint();
}
class MyPanel extends JPanel {
private Random r = new Random();
private boolean draw = false;
public MyPanel() {
Timer timer = new Timer(r.nextInt(5000) + 1000, new ActionListener() {
public void actionPerformed(ActionEvent ev) {
draw = true;
repaint();
}
});
timer.setRepeats(false);
timer.start();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (draw) {
g.setColor(Color.red);
g.fillOval(100, 100, 100, 100);
}
}
}
}
Also, don't forget to call the super's paintComponent method from within your override.
If you need to change colors, give the JPanel a Color field, say called color and change it's value from within the Timer, and then call repaint(). Again within paintComponent, use the value of that field to draw the oval with. Also in this situation, the Timer should repeat, so get rid of timer.setRepeats(false) in that situation.

The timer works asynchronously and paintComponent finishes before finishing the work of timer.

How to make JScrollPane (In BorderLayout, containing JPanel) smoothly autoscroll

I'm trying to have a JPanel of varying size (potentially much wider than the standard screen) inside of a JScrollPanel. Currently it works out great, and I have configured the scrollbars to work fine manually, however I would like the JPanel to "scroll" constantly to the left, so that over time the whole thing is displayed. All of the answers I found are specific to JTextArea and use Carets, or use rectToVisible. Neither of these will work because I'm trying to scroll internally to a single JPanel.
I've included what I believe to be all of the relevant code below.
center is the JPanel (of which Grid is a subclass, used to paint specifically a grid with some specific cells colored) with a BorderLayout that I would like to autoscroll.
public GuiViewFrame(Song playMe) {
String[][] songArray = playMe.to2DArray();
this.displayPanel = new ConcreteGuiViewPanel(playMe);
main = new JPanel();
main.setLayout(new BorderLayout());
displayPanel.setLayout(new BorderLayout());
center = new Grid(playMe);
labels = new Labels(playMe);
horiz = new Horiz(playMe);
center.setPreferredSize(new Dimension(10 * songArray.length, 10 * songArray[0].length));
horiz.setPreferredSize(new Dimension(10 * songArray.length, 10));
horiz.setVisible(true);
main.add(center, BorderLayout.CENTER);
main.add(horiz, BorderLayout.NORTH);
scroll = new JScrollPane(main,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
add(scroll, BorderLayout.CENTER);
labels.setPreferredSize(new Dimension(20, 10 * songArray[0].length));
labels.setVisible(true);
add(labels, BorderLayout.WEST);
JScrollBar horiz = scroll.getHorizontalScrollBar();
InputMap im = horiz.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
im.put(KeyStroke.getKeyStroke("RIGHT"), "positiveUnitIncrement");
im.put(KeyStroke.getKeyStroke("LEFT"), "negativeUnitIncrement");
im.put(KeyStroke.getKeyStroke("HOME"), "minScroll");
im.put(KeyStroke.getKeyStroke("END"), "maxScroll");
this.setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
this.pack();
}
The project as a whole is to generate a view for playing music that combines MIDI and a GUI, but right now once MIDI plays enough of the song, the relevant notes are off screen. I would like to scroll at a rate to keep pace with MIDI.

You can set the value of the horizontal scrollbar to control what is currently visible:
JScrollBar horizontal = scroll.getHorizontalScrollBar();
horizontal.setValue( horizontal.getValue() + ??? );
You would need to use a Swing Timer to schedule the scrolling at an appropriate interval.
Simple example of using a Timer to scroll text:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class TimerTest extends JPanel implements ActionListener
{
JLabel timeLabel;
JLabel scrollLabel;
public TimerTest()
{
setLayout( new BorderLayout() );
timeLabel = new JLabel( new Date().toString() );
add(timeLabel, BorderLayout.NORTH);
scrollLabel = new JLabel( "Some continuously scrolling text!! " );
add(scrollLabel, BorderLayout.SOUTH);
int time = 1000;
javax.swing.Timer timer = new javax.swing.Timer(time, this);
timer.setInitialDelay(1);
timer.start();
}
public void actionPerformed(ActionEvent e)
{
timeLabel.setText( new Date().toString() );
String oldText = scrollLabel.getText();
// Scroll right to left
String newText = oldText.substring(1) + oldText.substring(0, 1);
// Scroll left to right
// int length = oldText.length();
// String newText = oldText.substring(length-1, length)
// + oldText.substring(0, length-1);
scrollLabel.setText( newText );
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add( new TimerTest() );
frame.setLocationByPlatform( true );
frame.pack();
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}

One possible solution might be to take advantage of JComponent#scrollRectToVisible and a Swing Timer
For example...
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JViewport;
import javax.swing.Scrollable;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ScrollTest {
public static void main(String[] args) {
new ScrollTest();
}
public ScrollTest() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new JScrollPane(new TestPane()));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel implements Scrollable {
public TestPane() {
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JViewport viewport = (JViewport) getParent();
Rectangle viewRect = viewport.getViewRect();
if (viewRect.x + viewRect.width < getWidth()) {
viewRect.x += 2;
scrollRectToVisible(viewRect);
} else {
((Timer)e.getSource()).stop();
}
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(1000, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawLine(0, 0, getWidth(), getHeight());
g2d.dispose();
}
#Override
public Dimension getPreferredScrollableViewportSize() {
return new Dimension(200, 200);
}
#Override
public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
return 64;
}
#Override
public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
return 64;
}
#Override
public boolean getScrollableTracksViewportWidth() {
return getPreferredSize().width <= getParent().getSize().width;
}
#Override
public boolean getScrollableTracksViewportHeight() {
return getPreferredSize().height <= getParent().getSize().height;
}
}
}

Using java timer in JFrame

when handset button pressed I want to green button color change red.After a certain time,again
I want to green button.I dont use timer class.Please help me.
For example my code
if (e.getSource() == handsetbutton) {
text1.setBackground(Color.RED);
// What l have to add here?
}

Run this example. I use a Swing Timer and set the delay to 4 seconds. When the button is pressed, it fires an action to change the color and start the timer. When the 4 seconds is up, the color changes back
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class GreenToRed extends JPanel {
private Color color = Color.RED; // global color object
static JButton button = new JButton("Change");
private Timer timer = null;
public GreenToRed(){
timer = new Timer(4000, new ActionListener(){ // Timer 4 seconds
public void actionPerformed(ActionEvent e) {
color = Color.RED; // after 4 seconds change back to red
repaint();
}
});
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
color = Color.GREEN; // change to green
repaint(); // repaint
timer.start(); // start timer
}
});
}
private static void createAndShowGui() {
JFrame frame = new JFrame();
frame.add(new GreenToRed(), BorderLayout.CENTER);
frame.add(button, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(color);
g.fillOval(getWidth() / 2 - 50, getHeight() / 2 - 50, 100, 100);
}
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}