drawRect inside of a UIViewControll

You need to call setNeedsDisplay and drawRect will be called automatically.
[yourView setNeedsDisplay:YES];

Thanks,

I am still having problems getting it to work.

I don't think I'm working with the drawRect class correctly, can you please take a look?

Here is part of my RootViewController that has the button that calls DrawRect:
.h--------------------------------------------------------------
#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController{
}

@end

.m--------------------------------------------------------------
#import "RootViewController.h"
#import "DrawRect.h"

@implementation RootViewController

- (IBAction) playBtn:(id)sender;


- (IBAction) playBtn:(id)sender {
      NSLog(@"Button Pressed");
      
      DrawRect *myRectView = [DrawRect alloc];
      [myRectView setNeedsDisplay:YES];            
}

DrawRect
.h--------------------------------------------------------------
#import <UIKit/UIKit.h>

@interface DrawRect : UIView {

}
@end

.m--------------------------------------------------------------
#import "DrawRect.h"


@implementation DrawRect


- (id)initWithFrame:(CGRect)frame {
    if ((self = [super initWithFrame:frame])) {
        // Initialization code
    }
    return self;
}


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
}


- (void)dealloc {
    [super dealloc];
}

@end


When I run this code I get the warning:
warning: 'DrawRect' may not respond to '-setNeedsDisplay:'

And when I click the button I get this message in the debugger:
-[DrawRect setNeedsDisplay:]: unrecognized selector sent to instance 0x59111d0

I think it has to do with the fact that I'm not using "initWithFrame" when I instantiate the DrawRect class, but I'm lost on how this is done or if I need it.

Thanks,
waffe

What is this:
  DrawRect *myRectView = [DrawRect alloc];

I thought you have a view and you need to redraw it. In this case you use setNeedsDisplay:
[theView setNeedsDisplay:YES];

You use a strange name: DrawRect. It is a class derived from UIView. But you create it in strange way: just call alloc method. This code is wrong. (I think, you wanted to create a view controller.)
If you use UIView you can create it with alloc and initWithFrame methods, for example:
UIView *myView = [[UIView alloc] initWithFrame:myRect];

Check also here:
Create UIView, UILabel and UIButton programmatically.
http://www.wmdeveloper.com/2010/07/create-uiview-uilabel-and-uibutton.html

Thanks pgnatyuk,

I'm going to look over the links you posted. I'm new to iPhone programming and this program is my first attempt at getting something of my own working. Drawing to a view view buttons seemed like an OK place to start.

Would a better name for drawRect be "rectView"?

And what is myRect in
UIView *myView = [[UIView alloc] initWithFrame:myRect];

maybe after a few more tuts i'll understand a bit better.

thanks,
4D

myView - that's the name of the UIView object.
I wish you good luck. Use the links I posted. Don't be in hurry and do not take long tutorials and programs for the beginning. You have enough to learn with one view.

Got it!!!

The first tutorial you posted for me was fantastic! I had done a few already but removing IB for a moment was just what I needed - more like what I'm used to.

I then did this parallel tutorial with IB:
http://www.switchonthecode.com/tutorials/creating-your-first-iphone-application-with-interface-builder

Thanks again,
waffe

You are welcome.