Question

I’m new to iPhone programming and can’t figure out how to use Core Graphics. The code I am testing with is:

- (void)drawRect:(CGRect)rect{
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextClearRect(ctx, rect);
CGContextSetRGBStrokeColor(ctx, 255, 255, 0, 1);
CGContextStrokeRect(ctx, CGRectMake(195, 195, 60, 60)); }

I put it in the ViewController.m file on a default View based application but nothing happens when the application is run.

Answer 1

drawRect is a method of the UIView class, not UIViewController. You need to create your own UIView subclass and implement that one’s drawRect. To actually use the class, just set the class name in the xib file that comes with the view.