Hello I am new to JAVA and recently studied graphics but got stuck on how to draw a circle (I learn on my own through Google) I would be happy if you help me with the following lines of code
(Do not refer to the background sub button)
public class Panel_ {
static JPanel panel1 = new JPanel();
public static Color randomColor() {
int r = (int) Math.round(Math.random() * 255 - 1);
int g = (int) Math.round(Math.random() * 255 - 1);
int b = (int) Math.round(Math.random() * 255 - 1);
Color R_col = new Color(r, g, b);
System.out.println(R_col);
return R_col;
}
public static void Panel() {
var color_changer = new JButton("To change color");
color_changer.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
panel1.setBackground(randomColor());
}
});
var Panel = new JPanel();
Panel.add(color_changer);
Panel.setBackground(Color.blue);
panel1.setBackground(Color.black);
panel1.setPreferredSize(new Dimension(400, 430));
var frame = new JFrame("Color changer");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(panel1, BorderLayout.NORTH);
frame.getContentPane().add(Panel, BorderLayout.SOUTH);
frame.pack();
frame.setSize(500, 500);
frame.setBackground(Color.blue);
frame.setVisible(true);
}
public void paintCircle(Graphics g) {
g.setColor(Color.blue);
g.fillOval(60, 80, 100, 100);
}
public static void main(String args[]) {
Panel();
}
}
Use paintComponent for panel1 which I changed the name to topPanel in the runnable code below:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import javax.swing.*;
public class Panel extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel topPanel;
private JPanel panel;
private JButton color_changer;
public Panel() {
initializeForm();
}
private void initializeForm() {
setAlwaysOnTop(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBackground(Color.blue);
color_changer = new JButton("To change color");
color_changer.addActionListener((ActionEvent e) -> {
topPanel.setBackground(randomColor());
});
topPanel = new JPanel() {
private static final long serialVersionUID = 1L;
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.blue);
g.fillOval(60, 80, 100, 100);
};
};
panel = new JPanel();
panel.add(color_changer);
panel.setBackground(Color.blue);
topPanel.setBackground(Color.black);
topPanel.setOpaque(true);
topPanel.setPreferredSize(new Dimension(400, 430));
getContentPane().add(topPanel, BorderLayout.NORTH);
getContentPane().add(panel, BorderLayout.SOUTH);
pack();
setLocationRelativeTo(null);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(() -> {
new Panel().setVisible(true);
});
}
public static Color randomColor() {
int r = (int) Math.round(Math.random() * 255 - 1);
int g = (int) Math.round(Math.random() * 255 - 1);
int b = (int) Math.round(Math.random() * 255 - 1);
Color R_col = new Color(r, g, b);
System.out.println(R_col);
return R_col;
}
}
Related
I'm making a score-keeping program, but I'm running into a problem. What I've tried to do is have a JPanel at the top that contains two JPanels, which, in turn, contains two team names. I'm confused as to why the two JLabels at the top of the program aren't centered inside of the JPanels they're contained in.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ScoreFrame extends JFrame {
private static final Dimension SCREEN_SIZE = Toolkit.getDefaultToolkit().getScreenSize();
private static final int WIDTH = SCREEN_SIZE.width;
private static final int HEIGHT = SCREEN_SIZE.height;
private final JTextField[] nameField = new JTextField[] { new JTextField(), new JTextField() };
private final JLabel[] nameLabel = new JLabel[] { new JLabel("Team 1"), new JLabel("Team 2") };
private final GridBagLayout gridBag = new GridBagLayout();
private final GridBagConstraints constraints = new GridBagConstraints();
private final JPanel topPanel = new JPanel();
public ScoreFrame() {
super();
setResizable(false);
setSize(SCREEN_SIZE);
setLayout(gridBag);
setUndecorated(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
addKeyListener(new EscapeListener());
addComponents();
}
private void addComponents() {
addToTopPanel();
constraints.insets = new Insets(0, 0, (int) (HEIGHT * (double) 4 / 5), 0);
gridBag.setConstraints(topPanel, constraints);
add(topPanel);
}
private void addToTopPanel() {
final JPanel[] teamPanel = new JPanel[] { new JPanel(), new JPanel() };
topPanel.setLayout(gridBag);
topPanel.setSize(new Dimension(WIDTH, HEIGHT / 5));
Dimension teamPanelSize = new Dimension(WIDTH / 2, HEIGHT / 5);
teamPanel[0].setSize(teamPanelSize);
teamPanel[1].setSize(teamPanelSize);
Font nameFont = new Font("Times New Roman", Font.PLAIN, 50);
nameLabel[0].setFont(nameFont);
nameLabel[1].setFont(nameFont);
teamPanel[0].add(nameLabel[0]);
teamPanel[1].add(nameLabel[1]);
gridBag.setConstraints(teamPanel[0], constraints);
constraints.gridx = 1;
gridBag.setConstraints(teamPanel[1], constraints);
topPanel.add(teamPanel[0]);
topPanel.add(teamPanel[1]);
}
public void paint(Graphics g) {
super.paint(g);
int strokeSize = ((WIDTH + HEIGHT) / 2) / 300;
if (strokeSize < 1) {
strokeSize = 1;
}
final int fontSize = (int) (strokeSize * 12.5);
Graphics2D g2d = (Graphics2D) g;
g2d.setStroke(new BasicStroke(strokeSize));
g.drawLine(WIDTH / 2, 0, WIDTH / 2, HEIGHT / 5);
g.drawLine(WIDTH / 2, (int) (HEIGHT * (double) 105 / 400), WIDTH / 2, HEIGHT);
g.drawLine(0, HEIGHT / 5, WIDTH, HEIGHT / 5);
g.drawRect((int) (WIDTH * (double) 45 / 100), HEIGHT / 5, WIDTH / 10, (int) (HEIGHT * (double) 3 / 20));
g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.setFont(new Font("Times New Roman", Font.PLAIN, fontSize));
g.drawString("Errors", (int) (WIDTH * (double) 101 / 220), HEIGHT / 4);
}
private JFrame getFrame() {
return this;
}
public static void main(final String args[]) {
new ScoreFrame().setVisible(true);
}
public class EscapeListener implements KeyListener {
public void keyPressed(final KeyEvent event) {
if (event.getKeyCode() == 27) {
final int choice = JOptionPane.showConfirmDialog(getFrame(), "Do you want to exit the program?");
if (choice == 0) {
System.exit(0);
}
}
}
public void keyReleased(final KeyEvent event) {
}
public void keyTyped(final KeyEvent event) {
}
}
}
Invoking pack() is a critical step in using layouts. This example uses JLabel.CENTER and GridLayout to center the labels equally as the frame is resized. For simplicity, the center panel is simply a placeholder. This somewhat more complex example uses a similar approach along with java.text.MessageFormat.
Addendum: But how would I apply pack() to my code?
Simply invoke pack() as shown in the examples cited. I don't see an easy way to salvage your current approach of setting sizes extrinsically. Instead, override getPreferredSize() in a JPanel for your main content. No matter the screen size, your implementation of paintComponent() should adapt to the current size, for example.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/** #see https://stackoverflow.com/a/14422016/230513 */
public class Scores {
private final JLabel[] nameLabel = new JLabel[]{
new JLabel("Team 1", JLabel.CENTER),
new JLabel("Team 2", JLabel.CENTER)};
private void display() {
JFrame f = new JFrame("Scores");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel teamPanel = new JPanel(new GridLayout(1, 0));
teamPanel.add(nameLabel[0]);
teamPanel.add(nameLabel[1]);
f.add(teamPanel, BorderLayout.NORTH);
f.add(new JPanel() {
#Override
public Dimension getPreferredSize() {
return new Dimension(320, 240);
}
}, BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Scores().display();
}
});
}
}
My JPanel doesn't show up when my JButton is clicked. It does shows up when I add the JPanel in my go() method. However, once I tried to execute it by click the JButton, it doesn't work. The program does goes into the loop of the actionPeformed() method of the listener though.
public class MyShape
{
JFrame frame;
JPanel panel;
JButton drawButton;
public static void main (String[] args)
{
MyShape test = new MyRandomShape();
test.go();
}
public void go()
{
drawButton = new JButton("Draw Shape!");
drawButton.addActionListener(new DrawListener());
frame = new JFrame();
frame.add(drawButton, BorderLayout.NORTH);
frame.setSize(500,500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private class DrawListener implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
if(empty)
{
System.out.print("IN");
panel = new DrawPanel();
frame.add(panel, BorderLayout.CENTER);
}
}
}
private class DrawPanel extends JPanel
{
public void paintComponent(Graphics g)
{
super.paintComponents(g);
int randNo = (int)(Math.random() * 3);
int width = (int)(Math.random() * getWidth());
int height = (int)(Math.random() * getHeight());
int xpos = getWidth()/2-width/2;
int ypos = getHeight()/2-height/2;
int v1 = (int)(Math.random() * 256);
int v2 = (int)(Math.random() * 256);
int v3 = (int)(Math.random() * 256);
g.setColor(new Color(v1, v2, v3));
if(randNo == 0)
{
g.fillOval(xpos, ypos, width, height);
}
else if(randNo == 1)
{
g.fillRect(xpos, ypos, width, height);
}
else
{
int startAngle = (int)(Math.random() * 360);
int arcAngle = (int)(Math.random() * 360);
g.fillArc(xpos, ypos, width, height, startAngle, arcAngle);
}
}
}
}
How do I get the JPanel to show up once the button is clicked?
You have to call parentComponent.revalidate() every time you do one or more parentComponent.add(childComponent) (or change its children in other ways, such as reorder or remove them).
In your case, your code should be
private class DrawListener implements ActionListener {
public void actionPerformed(ActionEvent event)
{
if(empty)
{
System.out.print("IN");
panel = new DrawPanel();
frame.add(panel, BorderLayout.CENTER);
frame.revalidate(); // <---------- important
}
}
}
Few changes, check this
public static void main(String[] args) {
MyShape test = new MyShape();
test.go();
}
public void go() {
drawButton = new JButton("Draw Shape!");
drawButton.addActionListener(new DrawListener());
frame = new JFrame();
frame.getContentPane().add(drawButton, BorderLayout.NORTH);
panel = new DrawPanel();
frame.getContentPane().add(panel, BorderLayout.CENTER);
frame.setSize(500, 500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private class DrawListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
frame.getContentPane().remove(1);
panel = new DrawPanel();
frame.getContentPane().add(panel, BorderLayout.CENTER);
frame.repaint();
frame.validate();
}
}
I am trying to get a JPanel to appear inside of another JPanel. Currently, the JPanel is in an external JFrame and loads with my other JFrame. I want the JPanel to be inside the other JPanel so the program does not open two different windows.
Here is a picture:
The small JPanel with the text logs I want inside of the main game frame. I've tried adding the panel to the panel, panel.add(othePanel). I've tried adding it the JFrame, frame.add(otherPanel). It just overwrites everything else and gives it a black background.
How can I add the panel, resize, and move it?
Edits:
That is where I want the chatbox to be.
Class code:
Left out top of class.
public static JPanel panel;
public static JTextArea textArea = new JTextArea(5, 30);
public static JTextField userInputField = new JTextField(30);
public static void write(String message) {
Chatbox.textArea.append("[Game]: " + message + "\n");
Chatbox.textArea.setCaretPosition(Chatbox.textArea.getDocument()
.getLength());
Chatbox.userInputField.setText("");
}
public Chatbox() {
panel = new JPanel();
panel.setPreferredSize(new Dimension(220, 40));
panel.setBackground(Color.BLACK);
JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setPreferredSize(new Dimension(380, 100));
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
textArea.setEditable(false);
scrollPane
.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
userInputField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
String fromUser = userInputField.getText();
if (fromUser != null) {
textArea.append(Frame.username + ":" + fromUser + "\n");
textArea.setCaretPosition(textArea.getDocument()
.getLength());
userInputField.setText("");
}
}
});
panel.add(userInputField, SwingConstants.CENTER);
panel.add(scrollPane, SwingConstants.CENTER);
//JFrame frame = new JFrame();
//frame.add(panel);
//frame.setSize(400, 170);
//frame.setVisible(true);
}
Main frame class:
public Frame() {
frame.getContentPane().remove(loginPanel);
frame.repaint();
String capName = capitalizeString(Frame.username);
name = new JLabel(capName);
new EnemyHealth("enemyhealth10.png");
new Health("health10.png");
new LoadRedCharacter("goingdown.gif");
new Spellbook();
new LoadMobs();
new LoadItems();
new Background();
new Inventory();
new ChatboxInterface();
frame.setBackground(Color.black);
Frame.redHealthLabel.setFont(new Font("Serif", Font.PLAIN, 20));
ticks.setFont(new Font("Serif", Font.PLAIN, 20));
ticks.setForeground(Color.yellow);
Frame.redHealthLabel.setForeground(Color.black);
// Inventory slots
panel.add(slot1);
panel.add(name);
name.setFont(new Font("Serif", Font.PLAIN, 20));
name.setForeground(Color.white);
panel.add(enemyHealthLabel);
panel.add(redHealthLabel);
panel.add(fireSpellBookLabel);
panel.add(iceSpellBookLabel);
panel.add(spiderLabel);
panel.add(appleLabel);
panel.add(fireMagicLabel);
panel.add(swordLabel);
// Character
panel.add(redCharacterLabel);
// Interface
panel.add(inventoryLabel);
panel.add(chatboxLabel);
// Background
panel.add(backgroundLabel);
frame.setContentPane(panel);
frame.getContentPane().invalidate();
frame.getContentPane().validate();
frame.getContentPane().repaint();
//I WOULD LIKE THE LOADING OF THE PANEL SOMEWHERE IN THIS CONSTRUCTOR.
new ResetEntities();
frame.repaint();
panel.setLayout(null);
Run.loadKeyListener();
Player.px = Connect.x;
Player.py = Connect.y;
new Mouse();
TextualMenu.rect = new Rectangle(Frame.inventoryLabel.getX() + 80,
Frame.inventoryLabel.getY() + 100,
Frame.inventoryLabel.getWidth(),
Frame.inventoryLabel.getHeight());
Player.startMessage();
}
Don't use static variables.
Don't use a null layout.
Use appropriate layout managers. Maybe the main panel uses a BorderLayout. Then you add your main component to the CENTER and a second panel to the EAST. The second panel can also use a BorderLayout. You can then add the two components to the NORTH, CENTER or SOUTH as you require.
For example, using a custom Border:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Insets;
import java.awt.RadialGradientPaint;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.border.AbstractBorder;
#SuppressWarnings("serial")
public class FrameEg extends JPanel {
public static final String FRAME_URL_PATH = "http://th02.deviantart.net/"
+ "fs70/PRE/i/2010/199/1/0/Just_Frames_5_by_ScrapBee.png";
public static final int INSET_GAP = 120;
private BufferedImage frameImg;
private BufferedImage smlFrameImg;
public FrameEg() {
try {
URL frameUrl = new URL(FRAME_URL_PATH);
frameImg = ImageIO.read(frameUrl);
final int smlFrameWidth = frameImg.getWidth() / 2;
final int smlFrameHeight = frameImg.getHeight() / 2;
smlFrameImg = new BufferedImage(smlFrameWidth, smlFrameHeight,
BufferedImage.TYPE_INT_ARGB);
Graphics g = smlFrameImg.getGraphics();
g.drawImage(frameImg, 0, 0, smlFrameWidth, smlFrameHeight, null);
g.dispose();
int top = INSET_GAP;
int left = top;
int bottom = top;
int right = left;
Insets insets = new Insets(top, left, bottom, right);
MyBorder myBorder = new MyBorder(frameImg, insets);
JTextArea textArea = new JTextArea(50, 60);
textArea.setWrapStyleWord(true);
textArea.setLineWrap(true);
for (int i = 0; i < 300; i++) {
textArea.append("Hello world! How is it going? ");
}
setLayout(new BorderLayout(1, 1));
setBackground(Color.black);
Dimension prefSize = new Dimension(frameImg.getWidth(),
frameImg.getHeight());
JPanel centerPanel = new MyPanel(prefSize);
centerPanel.setBorder(myBorder);
centerPanel.setLayout(new BorderLayout(1, 1));
centerPanel.add(new JScrollPane(textArea), BorderLayout.CENTER);
MyPanel rightUpperPanel = new MyPanel(new Dimension(smlFrameWidth,
smlFrameHeight));
MyPanel rightLowerPanel = new MyPanel(new Dimension(smlFrameWidth,
smlFrameHeight));
top = top / 2;
left = left / 2;
bottom = bottom / 2;
right = right / 2;
Insets smlInsets = new Insets(top, left, bottom, right);
rightUpperPanel.setBorder(new MyBorder(smlFrameImg, smlInsets));
rightUpperPanel.setLayout(new BorderLayout());
rightLowerPanel.setBorder(new MyBorder(smlFrameImg, smlInsets));
rightLowerPanel.setBackgroundImg(createBackgroundImg(rightLowerPanel
.getPreferredSize()));
JTextArea ruTextArea1 = new JTextArea(textArea.getDocument());
ruTextArea1.setWrapStyleWord(true);
ruTextArea1.setLineWrap(true);
rightUpperPanel.add(new JScrollPane(ruTextArea1), BorderLayout.CENTER);
JPanel rightPanel = new JPanel(new GridLayout(0, 1, 1, 1));
rightPanel.add(rightUpperPanel);
rightPanel.add(rightLowerPanel);
rightPanel.setOpaque(false);
add(centerPanel, BorderLayout.CENTER);
add(rightPanel, BorderLayout.EAST);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private BufferedImage createBackgroundImg(Dimension preferredSize) {
BufferedImage img = new BufferedImage(preferredSize.width,
preferredSize.height, BufferedImage.TYPE_INT_ARGB);
Point2D center = new Point2D.Float(img.getWidth()/2, img.getHeight()/2);
float radius = img.getWidth() / 2;
float[] dist = {0.0f, 1.0f};
Color centerColor = new Color(100, 100, 50);
Color outerColor = new Color(25, 25, 0);
Color[] colors = {centerColor , outerColor };
RadialGradientPaint paint = new RadialGradientPaint(center, radius, dist, colors);
Graphics2D g2 = img.createGraphics();
g2.setPaint(paint);
g2.fillRect(0, 0, img.getWidth(), img.getHeight());
g2.dispose();
return img;
}
private static void createAndShowGui() {
FrameEg mainPanel = new FrameEg();
JFrame frame = new JFrame("FrameEg");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.setResizable(false);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class MyPanel extends JPanel {
private Dimension prefSize;
private BufferedImage backgroundImg;
public MyPanel(Dimension prefSize) {
this.prefSize = prefSize;
}
public void setBackgroundImg(BufferedImage background) {
this.backgroundImg = background;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (backgroundImg != null) {
g.drawImage(backgroundImg, 0, 0, this);
}
}
#Override
public Dimension getPreferredSize() {
return prefSize;
}
}
#SuppressWarnings("serial")
class MyBorder extends AbstractBorder {
private BufferedImage borderImg;
private Insets insets;
public MyBorder(BufferedImage borderImg, Insets insets) {
this.borderImg = borderImg;
this.insets = insets;
}
#Override
public void paintBorder(Component c, Graphics g, int x, int y, int width,
int height) {
g.drawImage(borderImg, 0, 0, c);
}
#Override
public Insets getBorderInsets(Component c) {
return insets;
}
}
Which would look like:
This question already has an answer here:
Closed 10 years ago.
Possible Duplicate:
Issues with ActionListener (Java)
I am trying to implement action listener on two buttons in JFrame, but the issue is one of the two button is performing both the functions; but i've not configured it to do so.
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class MyChangingCirlce implements ActionListener {
JButton colorButton, labelButton;
JLabel myLabel;
MyDrawPanel mdp;
JFrame frame;
public static void main(String[] args) {
MyChangingCirlce mcc = new MyChangingCirlce();
mcc.createFrame();
} // end of main
public void createFrame() {
frame = new JFrame();
colorButton = new JButton("Changing Colors");
labelButton = new JButton("Change Label");
myLabel = new JLabel("I'm a label");
mdp = new MyDrawPanel();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(BorderLayout.CENTER, mdp);
frame.getContentPane().add(BorderLayout.SOUTH, colorButton);
frame.getContentPane().add(BorderLayout.EAST, labelButton);
frame.getContentPane().add(BorderLayout.WEST, myLabel);
colorButton.addActionListener(this);
labelButton.addActionListener(this);
frame.setSize(300, 300);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == colorButton) {
frame.repaint();
} else {
myLabel.setText("That's it");
}
}
}
My labelButton is performing both the action only 1 time; i.e it changes the color of the circle along with the label text.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MyDrawPanel extends JPanel{
public void paintComponent(Graphics g)
{
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue= (int) (Math.random() * 255);
Color randomColor = new Color(red,green,blue);
g.setColor(randomColor);
g.fillOval(20,70,100,100);
}
}
You override colorButton and labelButton. So the 'else' is always kicking in. Changing the label will cause a redraw.
change
JButton colorButton = new JButton("Changing Colors");
JButton labelButton = new JButton("Change Label");
to
colorButton = new JButton("Changing Colors");
labelButton = new JButton("Change Label");
After writing myself a class to test it, I came about with this:
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.Date;
public class Foo implements ActionListener {
JButton colorButton, labelButton;
JLabel myLabel;
JFrame frame;
MyDrawPanel mdp;
public static void main(String[] args) {
Foo mcc = new Foo();
mcc.createFrame();
} //end of main
public void createFrame() {
frame = new JFrame();
colorButton = new JButton("Changing Colors");
labelButton = new JButton("Change Label");
myLabel = new JLabel("I'm a label");
mdp = new MyDrawPanel();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JSplitPane jsp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
mdp.setPreferredSize(new Dimension(150, 150));
jsp.setLeftComponent(mdp);
frame.setBounds(10, 10, 600, 600);
JPanel right = new JPanel();
right.add(BorderLayout.SOUTH, colorButton);
right.add(BorderLayout.EAST, labelButton);
right.add(BorderLayout.WEST, myLabel);
jsp.setRightComponent(right);
frame.getContentPane().add(jsp);
colorButton.addActionListener(this);
labelButton.addActionListener(this);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == colorButton) {
myLabel.setText("Color button's it");
frame.repaint();
} else {
myLabel.setText("That's it" + new Date().toString());
}
}
public class MyDrawPanel extends JPanel {
#Override
public void paintComponent(Graphics g) {
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
Color randomColor = new Color(red, green, blue);
g.setColor(randomColor);
g.fillOval(20, 70, 100, 100);
}
}
}
I've hit a wall (in my brain) trying to update my board on button presses. Am I right in thinking that the GameBoard class is the one that needs to be repaint()ed?
GameBoard.java
public class GameBoard extends Panel {
static Compass compass = new Compass();
private static final long serialVersionUID = 1;
Graphics2D g2d;
static final Dimension WINDOW_SIZE = new Dimension(1150, 800);
public void boardMaker() throws Exception {
JFrame frame = new JFrame("Display image");
JPanel panel = new JPanel();
/* unimportant stuff
.....
*/
//
DieRoll roll = new DieRoll("Roll Dies");
roll.setC(compass);
roll.setG2D(g2d);
//
Button button = new Button("new");
button.setGameBoard(this);
JPanel buttonPanel = new JPanel();
buttonPanel.add(button);
buttonPanel.add(roll);
buttonPanel.setPreferredSize(new Dimension(200,100));
frame.getContentPane().add(buttonPanel, BorderLayout.NORTH);
//
frame.getContentPane().add(panel);
frame.setVisible(true);
}
public void paint(Graphics g) {
// not important I think
}
}
Button.java
public class Button extends JButton implements ActionListener {
private static final long serialVersionUID = 1L;
JPanel panel = new JPanel();
JFrame frame = new JFrame();
Compass c = new Compass();
GameBoard gb = new GameBoard();
Button(String text) {
this.setText(text);
this.addActionListener(this);
}
void setGameBoard(GameBoard gb) {
this.gb = gb;
}
#Override
public void actionPerformed(ActionEvent e) {
gb.g2d.setColor(Color.black);
gb.g2d.fillRect(100, 100, 100, 200);
gb.repaint();
}
}
This gives a null pointer exception. So any idea how to repaint my GameBoard? I'm not mad if I've to rewrite everything because of stupidity! ;)
Thanks
You have the wrong idea about how to draw in Java. Components like Panels draw themselves, and all drawing takes place on the UI thread.
Check out this tutorial: docs.oracle.com/javase/tutorial/2d/index.html
The article Painting in AWT and Swing may offer some perspective on application-triggered painting. The example below illustrates the principle. Note that setForeground() calls repaint() automatically because the foreground color is a bound property, but you can always call it yourself.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class SwingPaint {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame f = new JFrame();
final GamePanel gp = new GamePanel();
f.add(gp);
f.add(new JButton(new AbstractAction("Update") {
#Override
public void actionPerformed(ActionEvent e) {
gp.update();
}
}), BorderLayout.SOUTH);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
});
}
private static class GamePanel extends JPanel {
private static final Random r = new Random();
public GamePanel() {
this.setForeground(new Color(r.nextInt()));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(320, 240);
}
public void update() {
this.setForeground(new Color(r.nextInt()));
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Dimension size = this.getSize();
int d = Math.min(size.width, size.height) - 10;
int x = (size.width - d) / 2;
int y = (size.height - d) / 2;
g.fillOval(x, y, d, d);
g.setColor(Color.blue);
g.drawOval(x, y, d, d);
}
}
}