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I am new to objC and MVC.  Need help with some basic stuff.

I am trying to create a redball programmatically using the view controller and UIImageView.  My view controller is also created programmatically and so is the view.  The ball does not appear (let alone animate it later) however I try on the simulator.  Any help appreciated.  What am i doing wrong?  Here is my code snippet … 

my app delegate.h:

@class HKViewController;

@interface HKAppDelegate : NSObject <UIApplicationDelegate> {

    UIWindow *window;

    HKViewController *viewController;

}

@property (nonatomic, retain) IBOutlet UIWindow *window;

@property (nonatomic, retain) HKViewController *viewController;

my view controller.m: (not showing memory warning and dealloc methods)

#import “HKViewController.h”

@implementation HKViewController

@synthesize redBallView;

-(void) onTimer {

pos = CGPointMake(160,300);

redBallView.center = CGPointMake(redBallView.center.x+pos.x,redBallView.center.y+pos.y);

if(redBallView.center.x > 320 || redBallView.center.x < 0)

pos.x = -pos.x;

if(redBallView.center.y > 320 || redBallView.center.y < 0)

pos.y = -pos.y;

}

// Implement loadView to create a view hierarchy programmatically, without using a nib.

- (void)loadView {

// Drawing code

UIGraphicsBeginImageContext(CGSizeMake(320,420));

CGContextRef ctx = UIGraphicsGetCurrentContext();

CGContextBeginPath(ctx);

CGContextAddArc(ctx,160,400,10,0,2*M_PI,1);

CGContextSetRGBFillColor(ctx, 1, 0, 0, 1);

CGContextFillPath(ctx);

UIImage *redBall = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

redBallView = [[UIImageView alloc] initWithImage:redBall];

redBallView.center = CGPointMake(160,300);

self.view = redBallView;

[self.view addSubview:redBallView];

//[self.view setNeedsDisplay];

[redBallView release];

pos = CGPointMake(14.0,7.0);

[NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];

}