Add extended rectangle class to jpanel

Question

I have a class, SheetGood, which extends Rectangle. At the moment I place these SheetGoods onscreen using absolute positions based off of the users resolution, but I'd like to let a layoutmanager take over this aspect.

To do so I'd like to add a SheetGood object to a JPanel, but can't as SheetGood does not extend JComponent.

Any ideas as to how I can get around this?

//edit// Will I run into issues if I force my program to run at a certain size and remove resizing options? Ie, a fixed size of 1280x1024 so I can continue placing SheetGoods how I have been and not have to worry about the other controls clipping them when their layout manager moves them around.

You could always create your own layout manager or just extend `java.awt.Component`. — James Taylor, Mar 23 '15 at 09:47
How can I extend awt.component if I've already extended rectangle though? — Mario Cappellano, Mar 23 '15 at 09:50
[You can extend more than one class in Java.](http://stackoverflow.com/questions/5836662/extending-from-two-classes) — James Taylor, Mar 23 '15 at 10:18
`but can't as SheetGood does not extend JComponent.` - Why not? You could probably add the required Rectangle functionality to your custom component. — camickr, Mar 23 '15 at 14:57

score 0 · Answer 1 · answered Mar 23 '15 at 10:17

To use absolute positioning, dont use a layout manager. You should set layout to null.

I suggest that: extends JPanel as rectangle and set a background color, and set bounds to the positions you want to place.

static class MyRectangle extends JPanel {
    int x, 
        y,
        width,
        height;
    Color bg;

    public MyRectangle(int x, int y, int width, int height, Color bg) {
        super();
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
        this.bg = bg;
        setBounds(x, y, width, height);
        setBackground(bg);
    }
}

public static void main(String[] args) throws Exception {
    JFrame frame = new JFrame("Test rectangle");

    MyRectangle rect1 = new MyRectangle(10, 10, 90, 90, Color.red),
                rect2 = new MyRectangle(110, 110, 90, 90, Color.yellow);

    JPanel contentPane = (JPanel)frame.getContentPane();
    contentPane.setLayout(null); //to make things absolute positioning

    contentPane.add(rect1);
    contentPane.add(rect2);

    frame.setSize(400, 400);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

Add extended rectangle class to jpanel

1 Answers1