Objective C: Triggering IBAction showInfo in viewDidAppear - objective-c

Question

I created my app using Utility Application template in Xcode 4.
I want my app to display the flip side on the first launch so that the user can enter a URL.
In my mainViewController I have:
- (void)viewDidAppear:(BOOL)animated
{
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if(![defaults stringForKey:#"url"]){
// Flip to the back page
[self showInfo: self];
NSLog(#"No url, flip");
}else{
NSLog(#"dont flip");
}
}
- (IBAction)showInfo:(id)sender
{
FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:#"FlipsideView" bundle:nil];
controller.delegate = self;
controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:controller animated:YES];
[controller release];
}
"No url, flip" is logged, and the showInfo method is called, but it does not flip.
What am I doing wrong?

Answer 1

just edit one line in your code.
- (void)viewDidAppear:(BOOL)animated
{
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if(![defaults stringForKey:#"url"]){
// Flip to the back page
[self performSelector:#selector(showInfo:) withObject:self afterDelay:0.1];
NSLog(#"No url, flip");
}else{
NSLog(#"dont flip");
}
}

Answer 2

Your showInfo: method is on the right track, sort of, but isn't going to work, I think. Here is an example of some code I have in an app that does what you're after, I believe:
PersonDetailViewController *pvc = [[PersonDetailViewController alloc]
initWithNibName:#"PersonDetailView" bundle:nil];
UIView *container = self.parentViewController.tabBarController.view;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.5];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight
forView:container cache:YES];
[container addSubview:pvc.view];
[pvc viewWillAppear:YES];
[self viewWillDisappear:YES];
[UIView commitAnimations];
The point of all this is that you have to give more info about the transition you are hoping to achieve. There are a number of UIView class methods (as shown here) that deal with setting up view transitions and other view-based animations.
So what's this doing? The code is adding the new view controller's view (pvc.view) as a subview of "container". In this app, the "container" view is the view that gets flipped out of the way as the new view (pvc.view) gets flipped in.
It is also important to call both the new view's viewWillAppear: and the old view's viewWillDisapear: so all the right stuff that you expect to happen when views come and go, happens. [This recipe may be considered "old school" by some. In the iPhone OS 2.x days (it wasn't called iOS back then), the Utility template had code similar to this, calling viewWillAppear and viewWillDisappear, etc. It still works today, fwiw. And the code shown here is in a shipping application on the app store, so its still kosher, so to speak. :-) ]
It is worth noting that in PersonDetailViewController (in this example) there is similar code that flips everything back, for consistency.