I am doing scroll view app for iPhone in xcode with iphone4.3 simulator.
but i got a warning message in the code :

```
-(void) keyboardDidShow:(NSNotification *)notif
{

if(keyboardVisible)
{
    NSLog(@"keyboard is already visible");
    return;
}

NSLog(@"resizing smaller for keyboard");

NSDictionary* info = [notif userInfo];

//warning message on following line

NSValue* aValue= [info objectForKey:UIKeyboardBoundsUserInfoKey];

CGSize keyboardSize = [aValue CGRectValue].size ;

CGRect viewFrame= self.view.frame;
viewFrame.size.height-= keyboardSize.height;

scrollView.frame= viewFrame;
keyboardVisible =YES;

}

```