Thread: Problem printing onto JPanel

I am trying to draw at my mouse a certain shape that I have set. I defined some shapes where they extend shape and draw circles and stuff. But when I click on panel it seems the paint doesnt put anything there. Debugger tells me shapes are saved though.

  public void mouseClicked(MouseEvent e) {
        currentX = e.getX();
 
        currentY = e.getY();
 
        Shape newShape = owner.currentBrush.clone();
        picture.add(newShape); 
        repaint();
    }
    public void paint(Graphics g){
 
            super.paint(g);
            for( int i = 0; i < myShapes.size(); i++ ){
                picture.get(i).draw(g); 
            }
 
        }
 
    public void draw(Graphics g){
            Graphics g2d = (Graphics2D) g;
 
            g2d.setColor(Color.BLUE);
 
            g2d.fillOval(getX(), getY(), radius, radius);
 
            g.drawOval(getX(), getY(), radius, radius);
        }

drawpanel:

import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.Color;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
 
public class DrawPanel extends JPanel implements MouseListener{
    Application owner;
    Stack myShapes = new Stack();
    Stack undoStack = new Stack();
    ArrayList<Shape> picture;
    int currentX = 10;
    int currentY = 10;
 
    public DrawPanel(Application parent){
        //this.setOpaque(true);
        this.owner = parent;
        this.setPreferredSize(new Dimension(600,800));
        this.setBackground(Color.WHITE);  
        this.setVisible(true);
        picture = new ArrayList<Shape>();
        addMouseListener(this);
        repaint();
        //addMouseMotionListener(this);
 
    }
 
    public void paint(Graphics g){
 
        super.paint(g);
        for( int i = 0; i < owner.myDraw.picture.size(); i++ ){
            owner.myDraw.picture.get(i).draw(g); 
            System.out.println("I BET THIS NEVER PRINTS");
        }
 
 
        System.out.println("I AM TRYING TO PAINT");
    }
    public void mousePressed(MouseEvent e) {
        currentX = e.getX();
        currentY = e.getY();
        //System.out.println(e.getY());
        Shape newShape = owner.currentBrush;
        picture.add(newShape); 
        repaint();
    }
    public void mouseEntered(MouseEvent e) {
    }
    public void mouseExited(MouseEvent e) {
    }
    public void mouseReleased(MouseEvent e){
    }
    public void mouseClicked(MouseEvent e) {
        owner.myDraw.currentX = e.getX();
 
        owner.myDraw.currentY = e.getY();
 
       // System.out.println(e.getY());
        Shape newShape = owner.getBrush();
        owner.myDraw.picture.add(newShape); 
        System.out.println(picture.size());
        repaint();
    }
 
    public void redo(){
        try{
            owner.myDraw.picture.add((Shape)undoStack.pop());
        } catch(LinkedListException p){
            System.out.println("Empty stack no poppy please");
        }
    }
 
    public void undo(){
        try{
            owner.myDraw.undoStack.push(picture.remove(picture.size()-1));
        } catch(LinkedListException e){
            System.out.println("Nothing to undo");
        }
    }
 
}

main app:

import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.io.Serializable;
 
public class Application extends JFrame{
    protected ButtonPanel myButton;
    protected DrawPanel myDraw;
 
    Shape currentBrush;
    JFrame frame;
    int currentX;
    int currentY;
 
    public Application() {
        frame = new JFrame("Main App");
        currentBrush = new Circle(5,5,5);
        this.myDraw = new DrawPanel(this);
        this.myButton = new ButtonPanel(this);
 
        frame.setSize(800, 800);
        frame.add(new ButtonPanel(this));
        frame.add(new DrawPanel(this));
        frame.setVisible(true);
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.LINE_AXIS));
 
    }
 
    public Application(int x, int y, int r) {
        System.out.println("Setting to custom brush");
        currentBrush = new Circle(x,y,r);
    }
 
    public void add(){
        try{
            myDraw.myShapes.insert(currentBrush);
        } catch(LinkedListException e){
            System.out.println("Good day sir");
        }
    }
 
    public Shape getBrush(){
        return new Shape(currentBrush);
    }
 
    public void setCurrentBrush(Shape newBrush){
    this.currentBrush = new Shape(newBrush);
    }
 
    public void setX(int nx){
    this.currentX = nx;
    }
 
    public void setY(int ny){
        this.currentY = ny;
    }
 
}

But when I click on panel it seems the paint doesnt put anything there. Debugger tells me shapes are saved though.

In the Application class constructor:

        this.myDraw = new DrawPanel(this);
        this.myButton = new ButtonPanel(this);
 
        frame.setSize(800, 800);
        frame.add(new ButtonPanel(this));
        frame.add(new DrawPanel(this));

Think about the code above for a second...how many instances of DrawPanel does the code create?

Originally Posted by copeg

In the Application class constructor:

        this.myDraw = new DrawPanel(this);
        this.myButton = new ButtonPanel(this);
 
        frame.setSize(800, 800);
        frame.add(new ButtonPanel(this));
        frame.add(new DrawPanel(this));

Think about the code above for a second...how many instances of DrawPanel does the code create? Very good catch though.

Yeah but I would just be drawing on the new Jpanel even so. Didn't seem to fix the not drawing.

the bluej folder http://www.filedropper.com/paintproject
Full code @ [Java] import java.util.*; import javax.swing.*; import java.awt.*; import java.io.S - Pastebin.com I think.

Yeah but I would just be drawing on the new Jpanel even so.

Since it creates two references, the drawing routine in the panel loops over an empty list (the non-visible JPanel)

for( int i = 0; i < owner.myDraw.picture.size(); i++ ){
            owner.myDraw.picture.get(i).draw(g); 
            System.out.println("I BET THIS NEVER PRINTS");
        }

Once that's fixed - look at where you code creates the Shape: x = 5 y = 5 with radius 5.

And for future reference, often I (and many others) will not look at code linked on 3rd party sites - post it here. In addition, posting as an SSCCE saves a lot of time and helps you get help faster (and in many cases, helps you better understand and sometimes even fix the problem)