Develop Reference

Using paintComponent() on a JFrame canvas being altered by a separate GUI

I am trying to make a JComponent application which uses two JFrames, one frame with alterable sliders and textfields for the graphical display of a firework on the second. When the "fire" button is pressed, a rendering of the firework should appear. However, I have found through placing strategic print statements, that my paintComponent() method does not run even though the conditional statement wrapping the code is satisfied. I have also double checked all of my other methods to ensure that correct values are generated at the correct times. After looking through all of the JComponent literature and questions I could find, I'm afraid I cannot get it to work - this problem is most likely derived from my lack of familiarity with the library. That being said, any advice no matter how rudimentary, will be much appreciated. Abridged code is below:
*The swing timer may also be the issue for I am not sure if I have used it correctly
[fireworksCanvas.java]
public class fireworkCanvas extends JComponent implements ActionListener{
private static final long serialVersionUID = 1L;
private ArrayList<Ellipse2D> nodes = new ArrayList<Ellipse2D>();
private ArrayList<Line2D> cNodes = new ArrayList<Line2D>();
private ArrayList<QuadCurve2D> bCurves = new ArrayList<QuadCurve2D>();
private int[] arcX;
private int[] arcY;
private Color userColor;
private Random rand = new Random();
private int shellX, shellY, fType, theta, velocity;
private Timer timer;
private int time;
private double g = -9.8; //gravity in m/s
public boolean explosivesSet;
public fireworkCanvas() {
time = rand.nextInt(3000) + 2000;
timer = new Timer(time, this); // 5 seconds
timer.start();
fType = 0;
}
#Override
public void paintComponent(Graphics g){
if (explosivesSet) {
System.out.println("fType" + fType);
super.paintComponent(g);
Graphics2D g2D = (Graphics2D) g;
g.setColor(Color.BLACK);
g.drawPolyline(arcX, arcY, arcX.length);
for (Ellipse2D e : nodes) {
System.out.println("painting nodes"); // NEVER PRINTS
g.setColor(userColor);
g.fillOval(shellX + (int) e.getX(), shellY + (int) e.getY(), (int) e.getWidth(), (int) e.getHeight());
}
for (Line2D l: cNodes) {
System.out.println("painting cNodes"); // NEVER PRINTS
g.setColor(determineColor("l"));
g.drawLine(shellX + (int) l.getX1(), shellY + (int) l.getY1(), shellX + (int) l.getX2(), shellY + (int) l.getY2());
}
for (QuadCurve2D c: bCurves) {
System.out.println("painting curves"); // NEVER PRINTS
g.setColor(determineColor("c"));
g2D.draw(c);
}
}
}
public Color determineColor(String type) {
// returns color
}
public void setExplosives() {
if (fType != 5 && fType != 0) {
nodes.clear(); // clears three array lists with FW components
cNodes.clear(); // these are the components to paint for the
bCurves.clear(); // firework explosion graphic
setArc(); // stores path of shell for a polyLine to be drawn
// builds and generates components for FW based on type chosen (fType)
setExplosivesSet(true);
repaint();
}
}
public void setArc() {
// builds int[] for shellX, shellY
}
#Override
public void actionPerformed(ActionEvent e) {
// nothing is here??
// should I use the action performed in some way?
}
[GUI.java]
public class GUI extends JFrame implements ActionListener, ChangeListener, ItemListener, MouseListener{
private static JFrame canvasFrame = new JFrame("Canvas");
private fireworkCanvas canvas = new fireworkCanvas();
private Choice fireworkChooser = new Choice();
private JSlider launchAngle = new JSlider();
private JSlider velocity = new JSlider();
private JSlider r = new JSlider();
private JSlider g = new JSlider();
private JSlider b = new JSlider();
private JPanel panel = new JPanel();
private JButton button = new JButton("Fire!");
private JLabel launchLabel = new JLabel("Launch Angle ");
private JLabel velocityLabel = new JLabel("Velocity ");
private JLabel rLabel = new JLabel("Red ");
private JLabel gLabel = new JLabel("Green ");
private JLabel bLabel = new JLabel("Blue ");
public static int fHeight = 500;
public static int fWidth = 500;
public GUI() {
this.add(panel);
panel.add(button);
panel.add(fireworkChooser);
panel.add(launchAngle);
panel.add(launchLabel);
panel.add(velocity);
panel.add(velocityLabel);
panel.add(r);
panel.add(rLabel);
panel.add(g);
panel.add(gLabel);
panel.add(b);
panel.add(bLabel);
addActionListener(this);
BoxLayout bl = new BoxLayout(getContentPane(), BoxLayout.Y_AXIS);
setLayout(bl);
fireworkChooser.addItemListener(this);
launchAngle.addChangeListener(this);
velocity.addChangeListener(this);
r.addChangeListener(this);
g.addChangeListener(this);
b.addChangeListener(this);
button.addActionListener(this);
fireworkChooser.add("Firework 1");
fireworkChooser.add("Firework 2");
fireworkChooser.add("Firework 3");
fireworkChooser.add("Firework 4");
fireworkChooser.add("Super Firework");
launchAngle.setMinimum(1);
launchAngle.setMaximum(90);
velocity.setMinimum(1);
velocity.setMaximum(50);
r.setMinimum(0);
r.setMaximum(255);
g.setMinimum(0);
g.setMaximum(255);
b.setMinimum(0);
b.setMaximum(255);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(600, 200);
}
#Override
public void stateChanged(ChangeEvent e) {
// sets FW variables
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == button) {
canvas.setfType(fireworkChooser.getSelectedIndex()+1);
canvas.setExplosives();
canvas.repaint();
canvas.setExplosivesSet(false);
System.out.println("button fired");
}
}
public static void createAndShowGUI() {
GUI gui = new GUI();
gui.pack();
gui.setLocationRelativeTo(null);
gui.setVisible(true);
gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fireworkCanvas canvas = new fireworkCanvas();
canvasFrame.pack();
canvasFrame.add(canvas);
canvasFrame.setLocationRelativeTo(null);
canvasFrame.setVisible(true);
canvasFrame.setSize(fWidth, fHeight);
canvasFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

First of all:
public fireworkCanvas()
Class names should start with an upper case character. All the other classes in your code follow this rule. Learn by example.
private Choice fireworkChooser = new Choice();
Choice is an AWT component don't mix AWT components in a Swing application. Use a JComboBox.
that my paintComponent() method does not run
fireworkCanvas canvas = new fireworkCanvas();
canvasFrame.pack();
canvasFrame.add(canvas);
You add the canvas to the frame AFTER you pack() the frame, so the size of the canvas is (0, 0) and there is nothing to paint.
The canvas should be added to the frame BEFORE the pack() and you should implement getPreferredSize() in your FireworkCanvas class so the pack() method can work properly.
Read the section from the Swing tutorial on Custom Painting for the basics and working examples to get you started.

Unable to make swing undo/redo system work for a simple paint program.

I followed steps from many articles but the undo system not behaving as expected. first, the undo button goes back correctly till the first edit but can't go beyond the first edit. also, when I click undo and then re-edit it circles back to the last edit. It's better if you execute the code and see yourself.
Another question, while I'm trying to figure out a solution I read that saving images in an Array is memory intensive, is that true even for this simple paint class, and what is the alternative? saving the image's graphic?
import java.awt.*;import java.awt.image.BufferedImage;import java.awt.event.*;import java.util.ArrayList;import javax.swing.*;import javax.swing.event.*;import javax.swing.undo.*;
public class Painter extends JFrame{
//attributes//
Painter.Canvas canvas;
JPanel controlPanel;
JButton undoButton;
JButton redoButton;
PainterHandler handler;
Container container;
//undo system elements//
UndoManager undoManager; // history list
UndoableEditSupport undoSupport; // event support
//constructor//
public Painter()
{
super("Painter-test");
controlPanel = new JPanel();
undoButton = new JButton("undo");
redoButton = new JButton("redo");
handler = new Painter.PainterHandler();
container = getContentPane();
canvas = new Painter.Canvas();
this.organizer();
}// end constructor
public void organizer()
{
controlPanel.setLayout(null);
controlPanel.setPreferredSize(new Dimension(120,350));
controlPanel.setBackground(null);
//add undo listeners to undo/redo buttons.
undoButton.addActionListener( new AbstractAction()
{
public void actionPerformed( ActionEvent evt )
{ undoManager.undo(); refreshCanvas(); refreshUndoRedo();}
});
redoButton.addActionListener(new AbstractAction()
{
public void actionPerformed(ActionEvent evt )
{ undoManager.redo(); refreshCanvas(); refreshUndoRedo(); }
});
// initilize the undo/redo system.
undoManager= new UndoManager();//history list
// event support, instance.
undoSupport = new UndoableEditSupport();
//add undoable edit listener to the support instance.
undoSupport.addUndoableEditListener(new UndoableEditListener()
{
public void undoableEditHappened (UndoableEditEvent event)
{
UndoableEdit edit = event.getEdit();
undoManager.addEdit( edit );
refreshUndoRedo();
}
});
refreshUndoRedo();
canvas.setPreferredSize(new Dimension(600,400));
//place buttons on panel.
undoButton.setBounds(10, 160, 80, 20);
redoButton.setBounds(10, 181, 80, 20);
//add components to panel.
controlPanel.add(undoButton);
controlPanel.add(redoButton);
//add panels to window.
container.add(canvas,BorderLayout.WEST);
container.add(controlPanel, BorderLayout.EAST);
}//end organizerTab3()
public void refreshCanvas() { canvas.repaint(); }
//refresh undo, redo buttons.
public void refreshUndoRedo()
{
// refresh undo
undoButton.setEnabled( undoManager.canUndo() );
// refresh redo
redoButton.setEnabled( undoManager.canRedo() );
}
//INNER CLASSES
ArrayList<BufferedImage> imagesArray = new ArrayList<BufferedImage>();
BufferedImage imageCopy;
Graphics graphics;
BufferedImage image;
int index;
private class Canvas extends JPanel
{
public Canvas()
{
//Panel properties
setSize(600,400);
setBackground(new Color(84,84,118));
image = new BufferedImage(getWidth(), getHeight(),BufferedImage.TYPE_INT_ARGB);
//add Listeners.
addMouseMotionListener(handler);
addMouseListener(handler);
}//end constructor
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
}//end inner class PaintPanel
private class PainterHandler extends MouseAdapter
{
#Override
public void mouseDragged(MouseEvent event)
{
if(event.getComponent().equals(canvas))
{
if (image != null)
{
// Paint into the image
graphics = image.getGraphics();
graphics.setColor(new Color(249,30,138));
graphics.fillOval(event.getX(), event.getY(), 20, 20);
imageCopy = new BufferedImage(canvas.getWidth(),canvas.getHeight(),BufferedImage.TYPE_INT_ARGB);
imageCopy.getGraphics().drawImage(image, 0, 0, null);
canvas.repaint();
}
}
}//end mouseDragged(MouseEvent event)
#Override
public void mouseReleased(MouseEvent event)
{
if(event.getComponent().equals(canvas))
{
//UNDO SYSTEM START//
//add image to the array.
imagesArray.add(imageCopy);
// get image's index.
index = imagesArray.indexOf(imageCopy);
//create AddEdit instance of type UndoableEdit.
UndoableEdit edit = new Painter.AddEdit(imagesArray, imageCopy,index);
// notify the listeners
undoSupport.postEdit( edit );
//UNDO SYSTEM END//
}
}
}//end MouseHandler class
private class AddEdit extends AbstractUndoableEdit
{
private ArrayList<BufferedImage> undoableImagesArray;
private BufferedImage undoableImage;
int undoableIndex;
public AddEdit(ArrayList<BufferedImage> v, BufferedImage img, int i)
{
undoableImagesArray = v;
undoableImage = img;
undoableIndex = i;
}
public void undo() throws CannotUndoException
{
undoableImagesArray.remove(undoableImage);
if(!undoableImagesArray.isEmpty())
image = (BufferedImage)undoableImagesArray.get(undoableImagesArray.size()-1);
canvas.repaint();
}
public void redo() throws CannotRedoException
{
undoableImagesArray.add(undoableImage);
image = (BufferedImage)undoableImagesArray.get(undoableImagesArray.size()-1);
canvas.repaint();
}
public boolean canUndo() { return true; }
public boolean canRedo() { return true; }
}//end class AddEdit
public static void main(String[] s)
{
Painter p = new Painter();
p.setSize(800, 500);
p.setVisible(true);
p.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}//END CLASS Painter

You don't use undoableIndex. In fact you should not remove the image from array but instead move the pointer.
canUndo() should return true if the list is not empty and the pointer >0
canRedo() should return true if the pointer!= size() of the list

How do I click a JLabel using MouseListener?

I am trying to make this program for minecraft, and now im just getting started. I want that if you click a label, it will check what label is it and will do something.
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent me) {
System.out.println(me.getX()+", "+me.getY()+".");
Object source = me.getSource();
int intx = me.getX();
int inty = me.getY();
if(me.getX()>=1 && me.getY()>=1 && me.getX()<=70 && me.getY()<=45){
permissionsframe.setLocation(810,250);
System.out.println(p1p.length);
permissionsframe.pack();
permissionsframe.setSize(200, 200);
permissionsframe.setVisible(true);
JLabel playerperms = new JLabel("Player "+p1s+" has "+p1p.length+" permissions.");
playerperms.setBounds(1, 1, 150, 150);
permissionsframe.add(playerperms);
System.out.println("You chose "+player1.getText()+".");
}
else{
System.out.println("You did not click any label.");
}
}
});
This selection area is adapted to the name I have now - NonameSL. But if the name will be longer or shorter, the selection area will obviuosly be different...
Is there a way to get the excact label? I tried if(source.equals(player1))(Player 1 is the label) but I placed the label in 1, 1 and I have to click the excact point that I defined the label in, X=1, Y=1. How can I make a mouse listener listen to a label?

There is no need to check if the mouse coordinates are inside your JLabel.
You can bind a Listener to every JLabel an process the click/press event in your MyMouseListener.class
To do so:
You have to add the MouseListener to every JLabel:
MyMouseListener myMouseListener = new MyMouseListener();
label01.setName("name01");
label01.addMouseListener(myMouseListener);
label02.setName("name02");
label02.addMouseListener(myMouseListener);
To identify the JLabel you could do something like this:
class MyMouseListener extends MouseAdapter {
#Override
public void mouseClicked(MouseEvent e) {
JLabel l = (JLabel) e.getSource();
if(l.getName().equals("name01"))
doSomething01();
else if(l.getName().equals("name02"))
doSomething02();
}
}

The correct way to do this is to use the .getComponent() method instead of the .getSource() since this is MouseEvent which is something different than ActionEvent.
Implement the Listener to your class:
public class Main implements MouseListener {
public static void main(String[] args) {
//setup JFrame and some label and then
label.addMouseListener(this);
}
#Override
public void mousePressed(MouseEvent e) {
if (e.getComponent().equals(label)) {
System.out.println("clicked");
}
}
//the other orderride methods..

How do I make an ImageIcon (or any kind of image really) visible without a JButton?

I'm working on a minesweeper game and I want to make the bomb (or in this case a panda image I created) to show up under the game space when it's pressed. At this point I just want to make it show up under every single space, I know how to do the randomizing of where it shows up after that, the problem is making it show up.
Right now the parts of my code that apply to this topic are in 2 different classes:
1st class
public class MSBoard extends JPanel implements ActionListener
{
int x = 8;
int y = 8;
public GridLayout gl = new GridLayout(x,y,0,0);
public MSBoxes boxarray[][] = new MSBoxes[x][y];
MSBoard()
{
super();
setLayout(gl);
for(int i=0;i<x;i++)
for (int j=0;j<y;j++)
{
boxarray[i][j] = new MSBoxes();
add(boxarray[i][j]);
}
}
public void actionPerformed(ActionEvent ae){}
}
2nd one
public class MSBoxes extends JPanel implements ActionListener
{
public JButton b1;
ImageIcon panda;
MSBoxes()
{
super();
panda = new ImageIcon("panda.gif");
b1 = new JButton();
add(b1);
b1.addActionListener(this);
b1.setVisible(true);
}
public void actionPerformed(ActionEvent ae)
{
if(b1 == ae.getSource())
{
b1.setVisible(false);
}
}
}

use JToggleButton for Minesweeper game
use putClientProperty
use ItemListener for JToggleButton

Simple ActionListener within a 2D array of JButtons

Okay so I am making a 2d array of JToggleButtons. I got the action listener up and going, but I have no way to tell which button is which.
If I click one, all it returns is something like
javax.swing.JToggleButton[,59,58,19x14,alignmentX=0.0,alignmentY=0.5,border=javax.swing.plaf.BorderUIResource$CompoundBorderUIResource#53343ed0,flags=296,maximumSize=,minimumSize=,preferredSize=,defaultIcon=,disabledIcon=,disabledSelectedIcon=,margin=javax.swing.plaf.InsetsUIResource[top=2,left=14,bottom=2,right=14],paintBorder=true,paintFocus=true,pressedIcon=,rolloverEnabled=false,rolloverIcon=,rolloverSelectedIcon=,selectedIcon=,text=]
Is there anyway to stick some sort of item or number in the button object to associate each button?
And then when the button is clicked I can retrieve that item or number that was given to it?
Here is my button generator code. (How could I make "int l" associate (and count) to each button made, when it is called, it will return that number, or something along those lines.
JToggleButton buttons[][] = new JToggleButton[row][col];
int l = 0;
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
buttons[i][j] = new JToggleButton("");
buttons[i][j].setSize(15,15);
buttons[i][j].addActionListener(new e());
panel.add(buttons[i][j]);
l++;
}
}
ActionListner
public class e implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
System.out.println(source);
}
}
variable "source" is what I use to get my data, so how can int l, be returned through "source" (as its unique value for the unique button clicked) as a button is clicked?
Thanks,
-Austin

very simple way is add ClientProperty to the JComponent, add to your definition into loop e.g.
buttons[i][j].putClientProperty("column", i);
buttons[i][j].putClientProperty("row", j);
buttons[i][j].addActionListener(new MyActionListener());
rename e to the MyActionListener and change its contents
public class MyActionListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
JToggleButton btn = (JToggleButton) e.getSource();
System.out.println("clicked column " + btn.getClientProperty("column")
+ ", row " + btn.getClientProperty("row"));
}
EDIT:
for MinerCraft clone isn't required to implements ony of Listeners, there is only about Icon, find out that in this code (don't implement any of Listeners anf remove used ItemListener)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ButtonsIcon extends JFrame {
private static final long serialVersionUID = 1L;
private Icon errorIcon = UIManager.getIcon("OptionPane.errorIcon");
private Icon infoIcon = UIManager.getIcon("OptionPane.informationIcon");
private Icon warnIcon = UIManager.getIcon("OptionPane.warningIcon");
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
ButtonsIcon t = new ButtonsIcon();
}
});
}
public ButtonsIcon() {
setLayout(new GridLayout(2, 2, 4, 4));
JButton button = new JButton();
button.setBorderPainted(false);
button.setBorder(null);
button.setFocusable(false);
button.setMargin(new Insets(0, 0, 0, 0));
button.setContentAreaFilled(false);
button.setIcon((errorIcon));
button.setRolloverIcon((infoIcon));
button.setPressedIcon(warnIcon);
button.setDisabledIcon(warnIcon);
add(button);
JButton button1 = new JButton();
button1.setBorderPainted(false);
button1.setBorder(null);
button1.setFocusable(false);
button1.setMargin(new Insets(0, 0, 0, 0));
button1.setContentAreaFilled(false);
button1.setIcon((errorIcon));
button1.setRolloverIcon((infoIcon));
button1.setPressedIcon(warnIcon);
button1.setDisabledIcon(warnIcon);
add(button1);
button1.setEnabled(false);
final JToggleButton toggleButton = new JToggleButton();
toggleButton.setIcon((errorIcon));
toggleButton.setRolloverIcon((infoIcon));
toggleButton.setPressedIcon(warnIcon);
toggleButton.setDisabledIcon(warnIcon);
toggleButton.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if (toggleButton.isSelected()) {
} else {
}
}
});
add(toggleButton);
final JToggleButton toggleButton1 = new JToggleButton();
toggleButton1.setIcon((errorIcon));
toggleButton1.setRolloverIcon((infoIcon));
toggleButton1.setPressedIcon(warnIcon);
toggleButton1.setDisabledIcon(warnIcon);
toggleButton1.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if (toggleButton1.isSelected()) {
} else {
}
}
});
add(toggleButton1);
toggleButton1.setEnabled(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
}

Just add the row and column data to each listener. You could add an explicit constructor, but I suggest adding a little method (which may have more added to it later).
buttons[i][j].addActionListener(e(i, j));
...
private ActionListener e(final int i, final int j) {
return new ActionListener() {
// i and j available here
...
(In JDK8 you should be able to use a lambda to reduce the syntax clutter.)
And then renaming it with a better name.

I made a minesweeper game and ran into a similar problem. One of the only ways you can do it, is to get the absolute location of the clicked button, then divide that by the x and y between buttons, so for me it was
if ((e.getComponent().getX() != (randx) * 25 && e.getComponent().getY() != (randy) * 25) &&bomb[randx][randy] == false) {
This code was to check if the area had bombs. So I had 25 x and y difference between location of bombs. That will just give you a general idea on how to do this.
I believe: (x - x spacing on left side) / buffer - 1 would work.

Instead of 'e.getSource()' you can always call 'e.getActionCommand()'. For each button you can specify this by:
JButton button = new JButton("Specify your parameters here"); /*you get these from getActionCommand*/
button.setText("title here"); /*as far as I remember*/