Show Top ViewController - ios

Question

I am reading code for an app that contains 40+ ViewController. How would you know which ViewController is the current.
What I have tried:
CBIntrospect: execute a UIAlertView with a
message:NSStringFromClass([self class])?
looked at adding
something to NotificationCenter and act on some method when a view
controller is piped?
Using the runtime.h to dynamically add a
method?
Any idea is appreciated

Answer 1

Try this:
- (UIViewController *)topViewController
{
return [self topViewController:self.window.rootViewController];
}
- (UIViewController *)topViewController:(UIViewController *)viewController
{
if (viewController.presentedViewController == nil) {
return viewController;
}
if ([viewController.presentedViewController isKindOfClass:[UINavigationController class]]) {
UINavigationController *navigationController = (UINavigationController *) viewController.presentedViewController;
UIViewController *topViewController = [navigationController.viewControllers lastObject];
return [self topViewController:topViewController];
}
UIViewController *presentedViewController = viewController.presentedViewController;
return [self topViewController:presentedViewController];
}

Answer 2

I often use [self.window recursiveDescription] to print all UIViews through my app. This is not VC, but can be also useful to you.
Just set the breakpoint everywhere you need and type (replace window with your key "UIWindow"):
[window recursiveDescription]
You'll see common result:
<UIWindow: 0xc0275c0; frame = (0 0; 320 568); gestureRecognizers = <NSArray: 0xc027b20>; layer = <UIWindowLayer: 0xc0276e0>>
| <UILayoutContainerView: 0xc0196b0; frame = (0 0; 320 568); autoresize = W+H; gestureRecognizers = <NSArray: 0xc022fa0>; layer = <CALayer: 0xc019790>>
| | <UINavigationTransitionView: 0xc011a60; frame = (0 0; 320 568); clipsToBounds = YES; autoresize = W+H; layer = <CALayer: 0xc00ebd0>>
| | | <UIViewControllerWrapperView: 0xb34ab10; frame = (0 0; 320 568); autoresize = W+H; layer = <CALayer: 0xb34abe0>>
| | | | <UIView: 0xc44a7c0; frame = (0 0; 320 568); autoresize = W+H; layer = <CALayer: 0xc44a820>>
| | | | | <UITableView: 0xdb4a000; frame = (0 0; 320 468); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0xc449ac0>; layer = <CALayer: 0xc448550>; contentOffset: {-0, -63}>
| | | | | | <UITableViewWrapperView: 0xc44a440; frame = (0 0; 320 468); autoresize = W+H; layer = <CALayer: 0xc44a510>>
| | | | | | | <WorkspaceCell: 0xc023a50; baseClass = UITableViewCell; frame = (0 1; 320 44); autoresize = W; layer = <CALayer: 0xc00cad0>>
| | | | | | | | <UITableViewCellScrollView: 0xc02c400; frame = (0 0; 320 44); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0xc02c980>; layer = <CALayer: 0xc02c610>; contentOffset: {0, 0}>
| | | | | | | | | <UITableViewCellContentView: 0xc022980; frame = (0 0; 320 43.5); opaque = NO; gestureRecognizers = <NSArray: 0xc02d2f0>; layer = <CALayer: 0xc02b0c0>>
| | | | | | | | | | <UIImageView: 0xc0233f0; frame = (15 7; 29 29); clipsToBounds = YES; autoresize = RM+TM+BM; userInteractionEnabled = NO; layer = <CALayer: 0xc0291e0>>
| | | | | | | | | | <UILabel: 0xc0262e0; frame = (60 11; 240 21); text = 'Alterplay'; clipsToBounds = YES; opaque = NO; autoresize = W+RM+TM+BM; userInteractionEnabled = NO; layer = <CALayer: 0xc0276a0>>
| | | | | | | | | | <UILabel: 0xc023130; frame = (15 7; 29 29); text = 'A'; clipsToBounds = YES; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0xc0231d0>>
| | | | | | | | | <_UITableViewCellSeparatorView: 0xc02e4e0; frame = (0 43.5; 320 0.5); layer = <CALayer: 0xc02e5b0>>
| | | | | | | | | <_UITableViewCellSeparatorView: 0xc02e850; frame = (0 0; 320 0.5); layer = <CALayer: 0xc02e8c0>>
| | | | | | <UIImageView: 0xc449210; frame = (0 465.5; 320 3.5); alpha = 0; opaque = NO; autoresize = TM; userInteractionEnabled = NO; layer = <CALayer: 0xc4494a0>>
| | | | | | <UIImageView: 0xc449680; frame = (316.5 414; 3.5 55); alpha = 0; opaque = NO; autoresize = LM; userInteractionEnabled = NO; layer = <CALayer: 0xc449760>>
| | | | | <UIView: 0xc44a850; frame = (0 518; 320 50); autoresize = W+TM; layer = <CALayer: 0xc44a8b0>>
| | | | | | <UIButton: 0xc4458a0; frame = (75 14; 172 22); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0xc4459d0>>
| | | | | | | <UIImageView: 0xb359ce0; frame = (27.5 4; 117 14); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xb359560>>
| | | | | <UIView: 0xc44a9f0; frame = (0 468; 320 50); autoresize = LM+RM+TM; layer = <CALayer: 0xc44aa50>>
| | | | | | <UIButton: 0xc447b10; frame = (101 10; 119 30); opaque = NO; autoresize = RM+BM; layer = <CALayer: 0xc447c00>>
| | | | | | | <UIButtonLabel: 0xb34c1a0; frame = (32 3; 55 24); text = 'Logout'; clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xb34c2b0>>
| | | | | <UIImageView: 0xc44ab00; frame = (0 424; 320 44); clipsToBounds = YES; opaque = NO; autoresize = LM+RM+TM; layer = <CALayer: 0xc44ab90>>
| | <UINavigationBar: 0xc019980; frame = (0 20; 320 44); opaque = NO; autoresize = W; gestureRecognizers = <NSArray: 0xc01b9f0>; layer = <CALayer: 0xc019ae0>>
| | | <_UINavigationBarBackground: 0xc01a180; frame = (0 -20; 320 64); opaque = NO; autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0xc01a2b0>>
| | | | <_UIBackdropView: 0xc01c0d0; frame = (0 0; 320 64); opaque = NO; autoresize = W+H; userInteractionEnabled = NO; layer = <_UIBackdropViewLayer: 0xc01dca0>>
| | | | | <_UIBackdropEffectView: 0xc01e6b0; frame = (0 0; 320 64); clipsToBounds = YES; opaque = NO; autoresize = W+H; userInteractionEnabled = NO; layer = <CABackdropLayer: 0xc01e970>>
| | | | | <UIView: 0xc01f2a0; frame = (0 0; 320 64); hidden = YES; opaque = NO; autoresize = W+H; userInteractionEnabled = NO; layer = <CALayer: 0xc01f400>>
| | | | <UIImageView: 0xc01a540; frame = (0 64; 320 0.5); userInteractionEnabled = NO; layer = <CALayer: 0xc01a610>>
| | | <UINavigationItemView: 0xc023490; frame = (111.5 8; 97.5 27); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xc023570>>
| | | | <UILabel: 0xc023920; frame = (0 3; 97.5 22); text = 'Workspaces'; clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xc023a20>>
| | | <_UINavigationBarBackIndicatorView: 0xc029150; frame = (8 12; 12.5 20.5); alpha = 0; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xc029240>>