How to paint an arrayList of shapes Java

Question

I am tasked with how to paint an arrayList of shapes in java.

I feel i have most of it right, there are two methods i am confused about however

the method in ShapeChooserPanel called public void setPoints(int x, int y)

Since Xs and Ys are arrays, how would i set the x and y values?

And the other is one is the final method in ShapeChooserPanel I cannot find out how to print the Shapes in the array, It should paint the current shape at the place the mouse was clicked.

My code is below

Main class:

import javax.swing.JFrame;

public class Lab2 {

    public static void main (String[] args) {


    JFrame myFrame = new JFrame("Lab 2");

    myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    myFrame.add(new ShapeChooserPanel());
    myFrame.pack();
    myFrame.setVisible(true);








    }
}

ShapeChooserPanel class

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.ArrayList;

public class ShapeChooserPanel extends JPanel {

private int currentX;
private int currentY;
private Color currentColor;
private int currentShape;
private JButton clearBtn;
private JRadioButton circle, square, triangle, box;
private DrawingPanel drawingPanel;
private JPanel controlsPanel;
//constants representing shape choice
private final int CIRCLE = 0;
private final int SQUARE = 1;
private final int TRIANGLE = 2;
private final int BOX = 3;
//constant delta used for setting distance between points
private final int DELTA = 25;
private int[] Xs;
private int[] Ys;
//store all the shapes to be painted UNCOMMENT when you have Shape.java defined
ArrayList<Shape> shapes;

public ShapeChooserPanel(){
    //provide some default values paints a circle at (10,10) in blue
    currentX = 10;
    currentY = 10;
    Xs = new int[4];//we will use all 4 points for the square, but only the first 3 for the triangle
    Ys = new int[4];
    setPoints(currentX,currentY);
    currentShape = CIRCLE;
    currentColor = Color.red;
    shapes = new ArrayList<Shape>();
    //instantiate the controls panel and set its layout to display everything in a single column
    controlsPanel = new JPanel();
    controlsPanel.setLayout(new BoxLayout(controlsPanel, BoxLayout.Y_AXIS));


    //TODO: add clear button *
    // TODO: define radio buttons *

    clearBtn = new JButton("Clear");
    clearBtn.addActionListener(new ClearListener());

    circle = new JRadioButton("Red Circle");
    circle.addActionListener(new ShapeListener());

    square = new JRadioButton("Cyan Square");
    square.addActionListener(new ShapeListener());

    triangle = new JRadioButton("Green Triangle");
    triangle.addActionListener(new ShapeListener());

    box = new JRadioButton("Blue Box");
    box.addActionListener(new ShapeListener());

    ButtonGroup group = new ButtonGroup();
    group.add(clearBtn);
    group.add(circle);
    group.add(square);
    group.add(triangle);
    group.add(box);

    controlsPanel.add(clearBtn);
    controlsPanel.add(circle);
    controlsPanel.add(square);
    controlsPanel.add(triangle);
    controlsPanel.add(box);



    //TODO: add radio buttons to group *
    //TODO add listeners to radio buttons *
    //TODO: add radio buttons to controls panel *

    drawingPanel = new DrawingPanel();

    drawingPanel.setBorder(BorderFactory.createLineBorder(Color.black));
    //TODO: set a border around the drawing panel *
    drawingPanel.setPreferredSize(new Dimension(200,200));
    drawingPanel.addMouseListener(new PanelListener());

    add(drawingPanel);
    add(controlsPanel);
    setPreferredSize(new Dimension (300,400));
}//end constructor

public void setPoints(int x, int y) {
    //TODO: set Xs and Ys *

    Xs[0] = x;
    Ys[0] = y;

}

private class ClearListener implements ActionListener{
    public void actionPerformed(ActionEvent ae){
        shapes.removeAll(shapes);
        drawingPanel.repaint();
    }
}
private class PanelListener implements MouseListener {
    public void mouseClicked(MouseEvent me) {

        currentX = me.getX();
        currentY = me.getY();
        //TODO: find coordinates of this mouse click *

        //TODO: add a new shape to the shapes list*

        shapes.addAll(shapes);

        setPoints(currentX, currentY);
        //TODO: call setPoints with current x and y values *
        drawingPanel.repaint();
    }
    public void mouseExited(MouseEvent me){}
    public void mouseEntered(MouseEvent me){}
    public void mouseReleased(MouseEvent me){}
    public void mousePressed(MouseEvent me){}
}
//Class to listen for radio button changes
private class ShapeListener implements ActionListener{
    public void actionPerformed(ActionEvent me){
        //TODO: determine which radio button was clicked *

        if(me.getSource() == circle){
            currentShape = CIRCLE;
            currentColor = Color.red;

          }

          if(me.getSource() == square){
              currentShape = SQUARE;
                currentColor = Color.cyan;

          }

          if(me.getSource() == triangle){
              currentShape = TRIANGLE;
                currentColor = Color.green;

          }

          if(me.getSource() == box){
              currentShape = BOX;
                currentColor = Color.blue;

          }


        //TODO: set current shape and color *
        drawingPanel.repaint();
    }
}
private class DrawingPanel extends JPanel {
    public void paintComponent(Graphics g) {
        super.paintComponent(g);



        //TODO: paint all the shapes in our list
    }
}
}

and my Shape class

import java.awt.Color;

public class Shape  {

private int x,y;
private int type;
private Color c;

public Shape(int x, int y, int type, Color c) {
    this.x = x;
    this.y = y;
    this.type = type;
    this.c = c;

}

public int x(int x) {

    return x;
}

public int y(int y) {

    return y;
}

public int type(int type) {

    return type;
}

public Color c(Color c) {

    return c;
}
}

Answer 1

super.paintComponent(g) invokes the paintComponent method from the superclass of JPanel (the JComponent class) to erase whatever is currently drawn on the panel. This is useful for animation, but not for setting color.

I guess you'll have to set the color of the shapes in your Arraylist<Shape> shapes when you will create them, nonetheless it could be helpfull to see the Shape class. Maybe you could create a function changeColor(Color ColorToBeSet) in this shape class and loop through the shapes ArrayList to call it at the end of your ShapeListener

Answer 2

You could...

Define an "abstract" concept of a shape, which has the basic properties (location and size) and which can paint itself...

public abstract class Shape {

    private int x, y;
    private int width, height;
    private Color c;

    public Shape(int x, int y, int width, int height, Color c) {
        this.x = x;
        this.y = y;
        this.c = c;
        this.width = width;
        this.height = height;
    }

    public int getHeight() {
        return height;
    }

    public int getWidth() {
        return width;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    public Color getColor() {
        return c;
    }

    public abstract void paint(Graphics2D g2d);
}

Then you can implement the individual shapes...

public class Rectangle extends Shape {

    public Rectangle(int x, int y, int width, int height, Color c) {
        super(x, y, width, height, c);
    }

    @Override
    public void paint(Graphics2D g2d) {
        g2d.setColor(getColor());
        g2d.drawRect(getX(), getY(), getWidth(), getHeight());
    }
}

public class Oval extends Shape {

    public Oval(int x, int y, int width, int height, Color c) {
        super(x, y, width, height, c);
    }

    @Override
    public void paint(Graphics2D g2d) {
        g2d.setColor(getColor());
        g2d.drawOval(getX(), getY(), getWidth(), getHeight());
    }
}

Then, you can simply call the paint method of each instance of Shape as required...

public class TestPane extends JPanel {

    private List<Shape> shapes;

    public TestPane() {
        shapes = new ArrayList<>(25);
        shapes.add(new Rectangle(10, 10, 20, 20, Color.RED));
        shapes.add(new Oval(15, 15, 40, 20, Color.RED));
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 200);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Shape shape : shapes) {
            Graphics2D g2d = (Graphics2D) g.create();
            shape.paint(g2d);
            g2d.dispose();
        }
    }

}