For iphone development, how to flip a UIImageView?

Question

I want to flip an imageView (left/right), but I can not find a UIView (or UIImageView) method to do that? any idea?

thanks!

Answer 1

Put your UIIMageView into a UIView and use this code (from the utility app project sample)

- (void)loadFlipsideViewController {

    FlipsideViewController *viewController = [[FlipsideViewController alloc] initWithNibName:@"FlipsideView" bundle:nil];
    self.flipsideViewController = viewController;
    [viewController release];

    // Set up the navigation bar
    UINavigationBar *aNavigationBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 44.0)];
    aNavigationBar.barStyle = UIBarStyleBlackOpaque;
    self.flipsideNavigationBar = aNavigationBar;
    [aNavigationBar release];

    UIBarButtonItem *buttonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(toggleView)];
    UINavigationItem *navigationItem = [[UINavigationItem alloc] initWithTitle:@"Test123"];
    navigationItem.rightBarButtonItem = buttonItem;
    [flipsideNavigationBar pushNavigationItem:navigationItem animated:NO];
    [navigationItem release];
    [buttonItem release];
}


- (IBAction)toggleView {    
    /*
     This method is called when the info or Done button is pressed.
     It flips the displayed view from the main view to the flipside view and vice-versa.
     */
    if (flipsideViewController == nil) {
        [self loadFlipsideViewController];
    }

    UIView *mainView = mainViewController.view;
    UIView *flipsideView = flipsideViewController.view;

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:1];
    [UIView setAnimationTransition:([mainView superview] ? UIViewAnimationTransitionFlipFromRight : UIViewAnimationTransitionFlipFromLeft) forView:self.view cache:YES];

    if ([mainView superview] != nil) {
        [flipsideViewController viewWillAppear:YES];
        [mainViewController viewWillDisappear:YES];
        [mainView removeFromSuperview];
        [infoButton removeFromSuperview];
        [self.view addSubview:flipsideView];
        [self.view insertSubview:flipsideNavigationBar aboveSubview:flipsideView];
        [mainViewController viewDidDisappear:YES];
        [flipsideViewController viewDidAppear:YES];

    } else {
        [mainViewController viewWillAppear:YES];
        [flipsideViewController viewWillDisappear:YES];
        [flipsideView removeFromSuperview];
        [flipsideNavigationBar removeFromSuperview];
        [self.view addSubview:mainView];
        [self.view insertSubview:infoButton aboveSubview:mainViewController.view];
        [flipsideViewController viewDidDisappear:YES];
        [mainViewController viewDidAppear:YES];
    }
    [UIView commitAnimations];
}

Answer 2

I think the only thing you're looking for is:

UIView's

+ (void)setAnimationTransition:(UIViewAnimationTransition)transition forView:(UIView *)view cache:(BOOL)cache;

and

UIViewAnimationTransitionFlipFromLeft,
UIViewAnimationTransitionFlipFromRight,

These animation transitions can only be used within an animation block. The transition is set on the container view and then the old view is swapped out for the new view, then the animation is committed.

Like:

CGContextRef context = UIGraphicsGetCurrentContext();

[UIView beginAnimations:nil context:context];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:yourContainerView cache:YES];
[yourContainerView exchangeSubviewAtIndex:0 withSubviewAtIndex:1];
[UIView commitAnimations];