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

Answer 1

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 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();
        }
    }

}