MousePressed

[Chris Roberts]

I was trying to get my MousePressed method to detect that I clicked on the
screen. When I click on the screen a circle is supposed to appear and be placed inside of a vector. How can I go about detecting this event in my code.

public class CircleDrawer3 extends JFrame {
 
Vector<Shape>Storage = new Vector<Shape>();  //declares a vector of shapes
    
    public CircleDrawer3 () {
Container content = getContentPane();

// Set size, location, color and close behavior
setSize(450,350);
setLocation(300,300);

//drawingPanel panel1 = new drawingPanel();
//    panel1.addMouseListener(new CircleListener());
 

content.setBackground(Color.WHITE);
    content.setLayout(new BorderLayout());   // specifying layout
//    content.add(panel1, BorderLayout.CENTER); 
    content.add(new drawingPanel(),BorderLayout.CENTER);
    
    
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }
    
    public class drawingPanel extends JPanel
    {   public final static int CIRCLE = 1, SQUARE = 2;
    private int shape;
    Dimension mySize = new Dimension(300, 300);
    
    protected void paintComponent(Graphics g)
    {
    super.paintComponent(g);
    
    //setSize(mySize);
         
        // register new instance of CircleListener for mouse events
        addMouseListener(new CircleListener());
    
    
    Circle temp;
      
 
        System.out.println(Storage);  // testing to see what's in the vector
    
    for(int i = 0; i<Storage.size(); i++)
    {
    System.out.println("Storing a circle");
    temp = (Circle)Storage.elementAt(i);
    g.setColor(Color.blue);
    g.fillOval(temp.getX(), temp.getY(),(int)( 2*temp.getRadius()),
    (int)(2*temp.getRadius()));
    }
    
    }
    
    // override getPreferredSize
    public Dimension getPreferredSize()
    {
    setSize(mySize);
    return mySize;
    }
    
    // set shape value and repaint drawingPanel
    public void draw(int shapeToDraw)
    {
    shape = shapeToDraw;
    repaint();
    }
    
    }
    
 
    /**
     * Inner class that inherits from MouseAadapter
     * It gets an empty definition of all the MouseListener
     * methods so it only needs to override the one(s) it
     * cares about
     */
    private class CircleListener extends MouseAdapter {
 
/** radius of circle to draw */
private int radius = 25;

public void mousePressed(MouseEvent event) {
   
    // Get the graphics context to draw on
    Graphics g = getGraphics();
    
    Circle c = new Circle();   // creates an instance of Circle
    Storage.add(c);            // adds a Circle to the vector 
   // getPoint(Storage);  // get the x and y position
    

    // Set the drawing color to blue and draw circle
    // Since the x,y passed to the fillOval is upper-left corner
    // need to offset to make centered at click
    g.setColor(Color.blue);
    g.fillOval(event.getX()-radius,
       event.getY()-radius,
       2*radius,
       2*radius);
}
    }
    public static void main (String[] args) {
CircleDrawer3 cd = new CircleDrawer3();
cd.setVisible(true);
    }
}
 

[Craig Wood]

Add your mouse listener to your JPanel (that does the drawing) in it's constructor. The constructor is the place to build and initialize variables for your class. I am still using j2se 1.4 so am unable to use the generic form of the Storage vector; thus the declaration of shapes. I made up a Circle class that would allow the code to compile. The general idea in drawing, though you are free to do things any way you want, is to add the Circles to the vector in the mouse code and draw them in the rendering component (the JPanel DP below). I changed the names to avoid name–clashing in your VM.

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
 
public class CD3 extends JFrame {
 
    //Vector<Shape>Storage = new Vector<Shape>(); //declares a vector of shapes
    Vector shapes;
 
    public CD3 () {
        // Set size, location, color and close behavior
        setSize(450,350);
        setLocation(300,300);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
 
        Container content = getContentPane();
        content.setBackground(Color.WHITE);
        content.setLayout(new BorderLayout());    // specifying layout
        content.add(new DP(), BorderLayout.CENTER);
    }
 
    public class DP extends JPanel {
        public final static int CIRCLE = 1, SQUARE = 2;
        private int shape;
        Dimension mySize = new Dimension(300, 300);
 
        public DP()
        {
            shapes = new Vector();
            // register new instance of CircleListener for mouse events
            addMouseListener(new CircleListener());
        }
 
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Circle temp;
            for(int i = 0; i < shapes.size(); i++) {
                temp = (Circle)shapes.elementAt(i);
                g.setColor(Color.blue);
                g.fillOval(temp.getX(), temp.getY(),(int)(2 * temp.getRadius()),
                                                    (int)(2 * temp.getRadius()));
            }
        }
 
        // override getPreferredSize 
        public Dimension getPreferredSize() {
            return mySize;
        }
 
        // set shape value and repaint drawingPanel 
        public void draw(int shapeToDraw) {
            shape = shapeToDraw;
            repaint();
        }
    }
 
    /**
     * Inner class that inherits from MouseAadapter
     * It gets an empty definition of all the MouseListener
     * methods so it only needs to override the one(s) it
     * cares about
     */
    private class CircleListener extends MouseAdapter {
        public void mousePressed(MouseEvent event) {
            Circle c = new Circle(event.getX(), event.getY()); // creates an instance
                                                               //   of Circle
            shapes.add(c);                             // adds a Circle to the vector 
            repaint();
        }
    }
 
    public static void main (String[] args) {
        CD3 cd = new CD3();
        cd.setVisible(true);
    }
}
 
class Circle {
    int x, y;
    /** radius of circle to draw */
    private int radius = 25;
 
    public Circle(int x, int y) {
        this.x = x;
        this.y = y;
    }
 
    public int getX() {
        return x;
    }
 
    public int getY() {
        return y;
    }
 
    public int getRadius() {
        return radius;
    }
}