drawing on a jpanel

> i can just see a blank panel, with nothing on it...

Here is your code with a really nasty main() method added so it can be compiled

and run:import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.Image;

import java.awt.Toolkit;

import javax.swing.JFrame;

import javax.swing.JPanel;

public class CanvasPanel extends JPanel {

Image[] images = new Image[10];

int frame = 0;

public CanvasPanel() {

setSize(200,200);

images[0] = Toolkit.getDefaultToolkit().getImage("1.gif");

}

public void paintComponent (Graphics g) {

super.paintComponent(g);

Graphics2D g2 = (Graphics2D)g;

g.drawImage(images[0], 0, 0, this);

g2.fillRect(0,0,50,50);

g2.drawLine(0,0,350,450);

g.drawString("String", 0, 20);

}

public static void main(String args[]) {

JFrame test = new JFrame("Test");

test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

test.add(new CanvasPanel());

test.setVisible(true);

}

}

When run the rectangle, line and image all appear. If you don't see them,

then the problem is with the code you haven't posted yet.

A few thoughts:

There is no explicit repaint() call in this code: generally you let the runtime decide

what needs repainting and when. repaint() is useful when you want to inform the

runtime that something needs repainting because it has changed.

Why is this thing a panel, and not a component? As the API documentation says "A

component is an object having a graphical representation that can be displayed on

the screen and that can interact with the user". We use a panel when we want a

thing that we can attach other components to. If you start attaching other

components to this panel it will interfere with the paintComponent() code.

(Finally, this should have been posted in the Swing forum, where more

knowledgable help is available. You've started here, so that's OK - but it's in

everybody's interests if questions are directed to the right place.)

pbrockway2a at 2007-7-10 2:48:04 >