How to set delegate correctly by code (without xib)?

[timsims]

1. I create an UIViewController instance in AppDelegate.m

2. In viewDidLoad of the UIViewController, create an instance of AFOpenFlowView,here is the code

   AFOpenFlowView *af = [[AFOpenFlowView alloc] initWithFrame:CGRectMake(10,20,300,400)];

   NSString *imageName;
   for (int i=0; i < 10; i++) {
   imageName = [[NSString alloc] initWithFormat:@"%d.jpg", i];
   [af setImage:[UIImage imageNamed:imageName] forIndex:i];
   [imageName release];

   }
   [af setNumberOfImages:10];

   [self.view addSubView:af];

That this point , if I run the code, Cover flow work fines except delegate method

And the problem comes, no matter use [af setViewDelegate:self] or [af setViewDelegate:(AFOpenFlowView *)self], my app will crash after switch a Cover

Any idea how should I set the delegate properly?

Thank you guys!