Develop Reference

Am not able to test for actions, and therefore cannot update Applet [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 6 years ago.
Improve this question
My main problem is I am confused on where to implement the listener classes so that whenever an action is made (whether it be a key press or mouse click) the applet is updated. I realize my compiling issue is from my CanvasPanel method in my CanvasPanel class and not having arguments in my actionPerformed method. However at this point I'm not sure how these listeners should be implemented correctly. Have tried looking over different questions already posted, so sorry if it is a duplicate.
Here is my code:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class WholePanel extends JPanel
{
private Color foregroundColor, backgroundColor;
private int currentDiameter, x1, y1;
private CanvasPanel canvas;
private JPanel buttonPanel;
private JRadioButton filledRadio, unfilledRadio;
private JRadioButton redRadio, greenRadio;
private boolean fill;
private Graphics myCircle;
public WholePanel()
{
backgroundColor = Color.CYAN;
foregroundColor = Color.RED;
currentDiameter = 100;
x1 = 200; y1 = 100;
unfilledRadio = new JRadioButton("Unfilled", true);
filledRadio = new JRadioButton("Filled", false);
redRadio = new JRadioButton("Red", true);
greenRadio = new JRadioButton("Green", false);
buttonPanel = new JPanel();
buttonPanel.add(unfilledRadio);
buttonPanel.add(filledRadio);
buttonPanel.add(redRadio);
buttonPanel.add(greenRadio);
canvas = new CanvasPanel();
JSplitPane sPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, buttonPanel, canvas);
setLayout(new BorderLayout());
add(sPane, BorderLayout.CENTER);
}
private class ColorListener implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
if (redRadio.isSelected()) {
greenRadio.setSelected(false);
backgroundColor = Color.RED;
}
else if (greenRadio.isSelected()) {
redRadio.setSelected(false);
backgroundColor = Color.GREEN;
}
// ...extra else/if statements
}
} // end of ColorListener
private class FillListener implements ActionListener
{
private boolean fill;
public void actionPerformed(ActionEvent event)
{
if (filledRadio.isSelected()) {
unfilledRadio.setSelected(false);
fill = true;
paintComponent(myCircle);
}
else if (unfilledRadio.isSelected()) {
filledRadio.setSelected(false);
fill = false;
paintComponent(myCircle);
}
}
}
private class CanvasPanel extends JPanel
{
public CanvasPanel( )
{
addKeyListener(new DirectionListener());
addMouseListener(new PointListener());
setBackground(backgroundColor);
//This method needs to be called for this panel to listen to keys
//When panel listens to other things, and go back to listen
//to keys, this method needs to be called again.
ColorListener.actionPerformed();
FillListener.actionPerformed();
requestFocus();
}
public void paintComponent(Graphics page)
{
super.paintComponent(page);
setBackground(backgroundColor);
page.setColor(foregroundColor);
page.drawOval(x1, y1, currentDiameter, currentDiameter);
if (fill == true) {
page.fillOval(x1, y1, currentDiameter, currentDiameter);
}
}
/** This method is overriden to enable keyboard focus */
public boolean isFocusable()
{
return true;
}
private class DirectionListener implements KeyListener
{
public void keyReleased(KeyEvent e) {}
public void keyTyped(KeyEvent e) {}
public void keyPressed(KeyEvent e)
{
currentDiameter = 100;
x1 = 200; y1 = 100;
int keyCode = e.getKeyCode();
// switch statement here
}
}
} // end of DirectionListener
public class PointListener implements MouseListener
{
public void mousePressed (MouseEvent event)
{
canvas.requestFocus();
}
public void mouseClicked (MouseEvent event) {}
public void mouseReleased (MouseEvent event) {}
public void mouseEntered (MouseEvent event) {}
public void mouseExited (MouseEvent event) {}
} // end of PointListener
} // end of Canvas Panel Class
} // end of Whole Panel Class

Some major problems in that code:
You're calling paintComponent directly, something you should never do. Instead change a state field of your class, call repaint()and then have paintComponent use the state field to decide what it should paint.
Same for using a Graphics field -- don't. Instead only use the Graphics object given to your paintComponent method by the JVM. The Swing Graphics tutorial will explain this.
You're trying to call your listener call back methods directly, which is the exact opposite of how listeners are supposed to work and negates the benefits of using listeners. Instead ADD your listeners to the components that will use them -- including adding the ActionListeners to the buttons that need them, the KeyListeners to the components that need them, MouseListeners... etc...
For instance, let's look at a much simpler example, one that uses two JRadioButtons and that's it:
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.*;
#SuppressWarnings("serial")
public class PartialPanel extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private static final int CIRC_W = 200;
private int circleX = 300;
private int circleY = 200;
private Color circleColor = null;
private ButtonGroup buttonGroup = new ButtonGroup();
private JRadioButton blueButton = new JRadioButton("Blue");
private JRadioButton redButton = new JRadioButton("Red");
public PartialPanel() {
ColorListener colorListener = new ColorListener();
blueButton.addActionListener(colorListener);
redButton.addActionListener(colorListener);
buttonGroup.add(blueButton);
buttonGroup.add(redButton);
JPanel buttonPanel = new JPanel();
buttonPanel.add(blueButton);
buttonPanel.add(redButton);
add(buttonPanel);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (circleColor != null) {
g.setColor(circleColor);
g.fillOval(circleX, circleY, CIRC_W, CIRC_W);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
} else {
return new Dimension(PREF_W, PREF_H);
}
}
private class ColorListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == blueButton) {
circleColor = Color.BLUE;
} else if (e.getSource() == redButton) {
circleColor = Color.RED;
}
repaint();
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
private static void createAndShowGui() {
PartialPanel mainPanel = new PartialPanel();
JFrame frame = new JFrame("PartialPanel");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
Here we add a ColorListener to the JRadioButtons. In the listener, we change the state of the class's circColor field, and then call repaint(). The paintComponent method then uses circColor's value to decide what color to use when drawing a circle.

Why won't my shapes draw on the JFrame?

I'm trying to get a specific shape to draw based on what the user clicks. Every other method in the program is working fine.
Here is a picture of what shows up currently:
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.*;
import java.awt.event.*;
public class Gui3 extends JFrame {
private JPanel mousepanel;
private JLabel statusbar;
private JList list;
private static String[] colornames = {"black","blue","red","white"};
private static Color[] colors = {Color.BLACK, Color.BLUE,Color.RED,Color.WHITE};
private JCheckBox cb;
private JCheckBox rect;
private JCheckBox oval;
private JCheckBox drawBox;
private boolean changeColor = true;
private boolean ableToDraw = true;
public Gui3(){
super("The title");
list = new JList(colornames);
list.setVisibleRowCount(4);
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setFixedCellHeight(15);
list.setFixedCellWidth(100);
add(new JScrollPane(list), BorderLayout.WEST);
list.addListSelectionListener(
new ListSelectionListener(){
public void valueChanged(ListSelectionEvent event){
if(changeColor==true){
mousepanel.setBackground(colors[list.getSelectedIndex()]);
}
else{
}
}
}
);
rect= new JCheckBox("Draw a rectangle");
oval= new JCheckBox("Draw a oval");
cb = new JCheckBox("Not able to change the color");
drawBox = new JCheckBox("Not able to draw shapes");
mousepanel = new JPanel();
mousepanel.setBackground(Color.WHITE);
add(mousepanel, BorderLayout.CENTER);
add(drawBox, BorderLayout.EAST);
add(cb, BorderLayout.NORTH);
mousepanel.add(rect,BorderLayout.EAST);
mousepanel.add(oval,BorderLayout.WEST);
statusbar = new JLabel("Default");
add(statusbar, BorderLayout.SOUTH);
HandlerClass handler = new HandlerClass();
mousepanel.addMouseListener(handler);
mousepanel.addMouseMotionListener(handler);
cb.addItemListener(handler);
drawBox.addItemListener(handler);
}
private class HandlerClass implements MouseListener, MouseMotionListener,ItemListener
{
#Override
public void mouseClicked(MouseEvent event) {
statusbar.setText(String.format("Clicked at %d, %d", event.getX(),event.getY()));
This is where what is selected is used to decided what to draw. It works by passing parameters to a method is the drawShape class; shown down below.
if(ableToDraw==true){
if(rect.isSelected()&&oval.isSelected()){
DrawShapes shapes = new DrawShapes();
shapes.whatToDraw(false,false);
}
}
else if(rect.isSelected()){
DrawShapes shapes = new DrawShapes();
shapes.whatToDraw(true, false);
shapes.setPosition(event.getX(), event.getY());
add(shapes);
}
else if(oval.isSelected()){
DrawShapes shapes = new DrawShapes();
shapes.whatToDraw(false, true);
shapes.setPosition(event.getX(), event.getY());
add(shapes);
}
else{
DrawShapes shapes = new DrawShapes();
shapes.whatToDraw(false,false);
}
}
#Override
public void mousePressed(MouseEvent event){
statusbar.setText("You pressed down the mouse");
}
#Override
public void mouseReleased(MouseEvent event){
statusbar.setText("You released the button");
}
#Override
public void mouseEntered(MouseEvent event){
statusbar.setText("You entered the area");
}
#Override
public void mouseExited(MouseEvent event){
statusbar.setText("The mouse has left the window");
}
//These are mouse motion events
#Override
public void mouseDragged(MouseEvent event){
statusbar.setText("You are dragging the mouse");
}
#Override
public void mouseMoved(MouseEvent event){
statusbar.setText("You are moving the mouse");
}
#Override
public void itemStateChanged(ItemEvent event){
if(cb.isSelected()){
changeColor=false;
}
else{
changeColor=true;
}
if(drawBox.isSelected()){
ableToDraw=false;
}
else{
ableToDraw=true;
}
}
}
}
This is the drawShapes class
import java.awt.*;
import javax.swing.*;
public class DrawShapes extends JPanel {
private int x,y;
private boolean ovals,rects;
public void paintComponent(Graphics g){
super.paintComponent(g);
if(ovals==false&&rects==true){
g.setColor(Color.BLUE);
g.fillRect(x,y,15,15);}
else if(ovals==true&&rects==false){
g.setColor(Color.BLUE);
g.fillOval(x, y, 30, 15);
}
else{
}
}
public void setPosition(int newX, int newY) {
this.x = newX;
this.y = newY;
repaint();
}
public void whatToDraw(boolean newrects, boolean newovals){
this.ovals=newovals;
this.rects=newrects;
repaint();
}
}

I would guess the problem is that you don't override the getPreferredSize() method of your DrawShapes class so there is nothing to paint. So you need to override the getPreferredSize() to return the actual size of your shape which in your case would appear to be (x + 30, y + 15) for your ovals and (x + 15, y + 15) rectangles.
You really should have separate classes for rectangles and ovals. Using if/else statements is not a good design and is not very flexible if you decide to add a "triangle" shape as your logic gets much more complicated.
However even if you do that you won't get what you expect because I'm guessing you add the DrawShapes component to a panel which by default is using a FlowLayout. So your shapes will just be displayed in a row on the panel, not where you click on the panel.
If you want the component to appear where you click then you need to set the size of the oval component to (30, 15) and the location of the component to (x, y). The painting of the shape would then be done at (0, 0) so the painting is relative to the component, not the panel. Then you need to set the layout of panel to null, so you can manually position each shape based on its location.
The other option is to not use real components, but just draw the shape onto a panel. Check out Custom Painting Approaches for examples of the two common ways incremental painting. It shows two different ways to do this depending on your exact requirement.
The examples show how to add Rectangles and you click/drag the mouse. So you need to modify the code to support different types of Shapes.

First I had to create a single instance of the drawShapes class, as stated by another user. Then the other part was that I messed up the logic, you should be able to draw only when ableToDraw==false meaning the button saying "not able to draw" isn't selected. That was bad naming on my part. Once that is done the code works fine.

How do I use mouse event dragging to draw line?

Okay so I added the recommended changes, however it (draggedMouse) still doesn't seem to be be connecting with the canvas even though I thought I am doing it right. I suppose it is not attached to the canvas, however I do not know how to go about doing this. I apologize in advance for my incompetence! I also included my Line class
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.ArrayList;
public class WholePanel extends JPanel
{
private Color currentColor;
private CanvasPanel canvas;
private JPanel leftPanel;
private JButton undo,erase;
private ArrayList<Line> lineList;
private Point ptStart,ptEnd, ptDrag;
private JRadioButton black,red,blue,green,orange;
private ArrayList<Line> drag;
public WholePanel()
{
currentColor = Color.black;
lineList = new ArrayList();
drag = new ArrayList();
undo = new JButton ("Undo"); // undo button
erase = new JButton("Erase"); // Erase button
black = new JRadioButton("Black"); black.setSelected(true); // setting black to the default line color
red = new JRadioButton("Red");
blue = new JRadioButton("Blue");
green = new JRadioButton("Green");
orange = new JRadioButton("Orange");
ButtonGroup group = new ButtonGroup(); // added buttons to group so only one can be selected at a time
group.add(black);
group.add(red);
group.add(blue);
group.add(green);
group.add(orange);
leftPanel = new JPanel(); // creates new JPanel that I can use to set the grid layout in and add the radio buttons
leftPanel.setLayout(new GridLayout(7,1));
leftPanel.add(black);
leftPanel.add(red);
leftPanel.add(blue);
leftPanel.add(green);
leftPanel.add(orange);
leftPanel.add(undo); // adds the undo button to the left panel above the erase button
leftPanel.add(erase); // adds the erase button to the left panel at the bottom
canvas = new CanvasPanel(); // creates the canvas panel
JSplitPane sp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftPanel, canvas); // splits the applet layout into two panels
setLayout(new BorderLayout());
add(sp);
undo.addActionListener( new ButtonListener()); // adding listener action for undo and erase buttons
erase.addActionListener( new ButtonListener());
black.addActionListener( new ComboListener()); // adding listener actions for radio buttons
red.addActionListener( new ComboListener());
blue.addActionListener( new ComboListener());
green.addActionListener( new ComboListener());
orange.addActionListener( new ComboListener());
//canvas.addMouseListener(new PointListener());
//canvas.addMouseMotionListener(new PointListener());
PointListener pl = new PointListener(canvas.getGraphics());
canvas.addMouseListener(pl);
canvas.addMouseMotionListener(pl);
}
//CanvasPanel is the panel where shapes will be drawn
private class CanvasPanel extends JPanel
{
//this method draws all shapes specified by a user
public void paintComponent(Graphics page)
{
super.paintComponent(page);
setBackground(Color.WHITE);
for(int i = 0; i< lineList.size(); i++){
(lineList.get(i)).draw(page);
}
}
} //end of CanvasPanel class
//ButtonListener defined actions to take in case
//"Undo", or "Erase" is chosen.
private class ButtonListener implements ActionListener
{
public void actionPerformed (ActionEvent event)
{
JButton source = (JButton)event.getSource();
String name = source.getText();
if (name.equals("Undo"))
{
if(lineList.size() > 0)
{
lineList.remove(lineList.size()-1);
}
}
else if (name.equals("Erase"))
{
lineList.clear();
}
repaint();
}
} // end of ButtonListener
// listener class to set the color chosen by a user using
// the color radio buttons
private class ComboListener implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
JRadioButton src = (JRadioButton)event.getSource();
String name = src.getText();
if(name.equals("Black"))
{
currentColor = Color.BLACK;
}
else if (name.equals("Red"))
{
currentColor = Color.RED;
}
else if (name.equals("Blue"))
{
currentColor = Color.BLUE;
}
else if (name.equals("Green"))
{
currentColor = Color.GREEN;
}
else if (name.equals("Orange"))
{
currentColor = Color.ORANGE;
}
}
}
// listener class that listens to the mouse
public class PointListener implements MouseListener, MouseMotionListener {
Graphics g;
public PointListener(Graphics g){
this.g = g;
}
//{
//in case that a user presses using a mouse,
//record the point where it was pressed.
public void mousePressed (MouseEvent event)
{
ptStart = event.getPoint();
}
//mouseReleased method takes the point where a mouse is released,
//using the point and the pressed point to create a line,
//add it to the ArrayList "lineList", and call paintComponent method.
public void mouseReleased (MouseEvent event)
{
ptEnd = event.getPoint();
Line line = new Line(ptStart.x,ptStart.y,ptEnd.x,ptEnd.y,currentColor);
lineList.add(line);
repaint();
}
public void mouseClicked (MouseEvent event) {}
public void mouseEntered (MouseEvent event) {}
public void mouseExited (MouseEvent event) {}
//mouseDragged method takes the point where a mouse is dragged
//and call paintComponent method
public void mouseDragged(MouseEvent event)
{
ptDrag = event.getPoint();
Line dragLine = new Line(ptStart.x,ptStart.y,ptDrag.x,ptDrag.y,currentColor);
dragLine.draw(g);
repaint();
}
public void mouseMoved(MouseEvent event) {}
} // end of PointListener
} // end of Whole Panel Class
And this is my Line class
import java.awt.*;
public class Line {
private int x1,x2,y1,y2;
private Color color;
public Line(int px1, int py1, int px2, int py2, Color pColor) // constructor that sets the color of the line as well as the coordinates
{
x1 = px1;
y1 = py1;
x2 = px2;
y2 = py2;
color = pColor;
}
public void draw(Graphics page)
{
page.setColor(color);// insert user color
page.drawLine(x1, y1, x2, y2);
}
}

You could add a Graphics variable and a constructor for PointListener such as
public class PointListener implements MouseListener, MouseMotionListener {
Graphics g;
//declare point variables
Point ptStart, ptEnd, ptDrag;
public PointListener(Graphics g){
this.g = g;
}
}
Edit: by declaring your Points this way, you make them (ptStart in particular) visible to mouseReleased and mouseDragged
This would enable you to draw your line in mouseDragged more easily because you can use
g.drawLine(ptStart.x, ptStart.y, ptDrag.x, ptDrag.y, currentColor);
Then when you add point listener, you just need to change the code to
//added PointListener object because you previously
//created new object for each statement
//meaning separate objects are listening for Mouse and MouseMotion
PointListener pl = new PointListener(canvas.getGraphics());
//this should work but one way or another
//you need to pass the Graphics object
canvas.addMouseListener(pl);
canvas.addMouseMotionListener(pl);

Swing Unable to draw circle

So this program that I wrote is supposed to draw a circle everytime click on the panel. For some reason I initially have a semicircle in the top right hand corner upon startup, and I can't get it to draw a circle. Can anyone see what's wrong with it? The circle should be 20 px in diameter, drawn with the clicked point at its center.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class QuizActionsInitial extends JFrame {
public JButton redButton = new JButton("red");
public JButton clearButton = new JButton("clear");
boolean isRed = false;
int x1,y1;
boolean clear = false;
CirclePanel myPanel;
public QuizActionsInitial() {
myPanel = new CirclePanel();
add(myPanel, BorderLayout.SOUTH);
JPanel southPanel = new JPanel(new FlowLayout());
clearButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
clear = true;
}
});
myPanel.addMouseListener(new CircleListener());
southPanel.add(redButton);
southPanel.add(clearButton);
add(southPanel, BorderLayout.NORTH);
pack();
setVisible(true);
} // end constructor
public class CirclePanel extends JPanel {
public CirclePanel() {
setPreferredSize(new Dimension(400,300));
setBorder(BorderFactory.createLineBorder(Color.BLUE, 2));
}
public void paintComponent(Graphics gc){
super.paintComponent(gc);
gc.fillOval(x1-10,y1-10,20,20);
}
} // end class CirclePanel
// end class CirclePanel
public class CircleListener extends MouseAdapter{
public void mouseClicked(MouseEvent e){
if (clear = false){
x1 = e.getX();
y1 = e.getY();
}
repaint();
clear = false;
}
}
public static void main(String args[]) {
new QuizActionsInitial();
} // end main
} // end class QuizActionsInitial

int x1,y1; initialise the values to 0, so you it will always draw an initial circle at -10x-10
Trying using a java.awt.Point class instead, and when it's null, don't paint anything...
//int x1,y1;
private Point point;
//...
public void paintComponent(Graphics gc){
super.paintComponent(gc);
if (point != null) {
gc.fillOval(point.x-10,point.y-10,20,20);
}
}
//...
public void mouseClicked(MouseEvent e){
if (!clear){
point = evt.getPoint();
}
clear = false;
repaint();
}
Oh, and if (clear = false){ is an assignment (making clear equal to false, so that the if statement will ALWAYS fail)

Custom painting in Java - drawing UI elements onto the JPanel

I am creating a drawing board program, basically a simplified version of MS Paint. It is working for the most part but when I draw on the board, the currently selected UI element shows up on the drawing area.
I tried paintComponent, which worked when I called super.paintComponent(g) (as one does) but it cleared the drawing area before I drew the next object. I overrode update and put a println statement in there and it is never being called.
The buttons at the top are red because I set the background to the bottom JPanel to red to see what the background of these buttons would be. So clearly they are part of the bottom JPanel. I am using a BorderLayout for the layout.
Here is my code (with some irrelevant bits removed):
public class JSPaint extends JFrame implements Serializable
{
private static final long serialVersionUID = -8787645153679803322L;
private JFrame mainFrame;
private JPanel bp;
private JButton ...
private DrawingArea da;
public JSPaint()
{
setTitle("JS Paint");
setSize(1024, 768);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Drawing area
da = new DrawingArea();
setLayout(new BorderLayout());
// add the buttons to the panel
buttonPanel();
// Add the drawing area
add(bp, BorderLayout.SOUTH);
bp.setBackground(Color.RED);
add(da, BorderLayout.CENTER);
da.setBackground(Color.BLUE);
setVisible(true);
}
// I put it here too just in case
#Override
public void update(Graphics g)
{
System.out.println("update in JSPaint called.");
paint(g);
}
/*
* Creates the panel for the buttons, creates the buttons and places them on
* the panel
*/
public void buttonPanel()
{
// Create the panel for the buttons to be placed in
bp = new JPanel();
saveButton = new JButton("Save");
loadButton = new JButton("Load");
//more buttons
bp.add(saveButton);
bp.add(loadButton);
//more buttons
// ActionListeners
colorButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
System.out.println("color");
da.color();
}
});
}
public class DrawingArea extends JPanel
{
private static final long serialVersionUID = -8299084743195098560L;
boolean dragged = false;
#Override
public void update(Graphics g)
{
System.out.println("Update in DrawingArea called");
paint(g);
}
/*
* Draws the selected shape onto the screen and saves it into a Stack.
*
*/
public void draw()
{
this.addMouseMotionListener(new MouseMotionListener()
{
public void mouseDragged(MouseEvent me)
{
dragged = true;
}
public void mouseMoved(MouseEvent me) {}
});
//more listeners...
});
}
/*
* Draws the selected String onto the screen when the mouse is held down.
*
*/
public void brush()
{
this.addMouseMotionListener(new MouseMotionListener()
{
public void mouseDragged(MouseEvent me)
{
// If we are in drawing mode, draw the String. Create a new
// Figure Object and push it onto the Stack
if(activeButton == "brush")
{
startPoint = me.getPoint();
Figure fig = new Figure("String", startPoint, null, currentColor);
// figures.push(calculate(fig));
toPaint.push(calculate(fig));
repaint();
}
}
public void mouseMoved(MouseEvent me) {}
});
}
// more of the same...
public void paint(Graphics g)
{
toSave.addAll(toPaint);
while(!toPaint.isEmpty())
{
Figure f = toPaint.pop();
String t = f.type;
if(f.color != null)
{
g.setColor(f.color);
}
switch(t)
{
case "Rectangle": g.drawRect(f.x1, f.y1, f.width, f.height);
break;
case "Oval": g.drawOval(f.x1, f.y1, f.width, f.height);
break;
case "Line": g.drawLine(f.x1, f.y1, f.x2, f.y2);
break;
case "Clear":
g.fillRect(0, 0, da.getWidth(), da.getHeight());
clearStack(toSave);
break;
case "String": g.drawString(f.toPrint, f.x1, f.y1);
break;
}
}
}
}
private class Figure implements Serializable
{
private static final long serialVersionUID = 4690475365105752994L;
String type, toPrint;
Color color;
Point start;
Point end;
int x1, y1, x2, y2, width, height;
public Figure(String figureType,
Point startPoint, Point endPoint, Color figureColor)
{
type = figureType;
color = figureColor;
start = startPoint;
end = endPoint;
}
// Rect, Oval
public Figure(String figureType, int figureX, int figureY,
int figureWidth, int figureHeight, Color figureColor)
{
type = figureType;
x1 = figureX;
y1 = figureY;
width = figureWidth;
height = figureHeight;
color = figureColor;
}
// more shapes
}
public static void main(String args[])
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new JSPaint();
}
});
}
}

If the currently selected UI element shows up on the drawing area, this can have only one reason: you are doing something wrong with the Graphics objects, possibly calling a translate on them, and not resetting the tranlation when you are done. (See this link for an example of translate used correctly).