How can I, in my view controller code, differentiate between:
Both presentingViewController and isMovingToParentViewController are YES in both cases, so are not very helpful.
What complicates things is that my parent view controller is sometimes modal, on which the to be checked view controller is pushed.
It turns out my issue is that I embed my HtmlViewController in a UINavigationController which is then presented. That's why my own attempts and the good answers below were not working.
HtmlViewController* termsViewController = [[HtmlViewController alloc] initWithDictionary:dictionary];
UINavigationController* modalViewController;
modalViewController = [[UINavigationController alloc] initWithRootViewController:termsViewController];
modalViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:modalViewController
animated:YES
completion:nil];
I guess I'd better tell my view controller when it's modal, instead of trying to determine.
This question is related to
ios
objective-c
swift
uiviewcontroller
uinavigationcontroller
Swift 4
var isModal: Bool {
return presentingViewController != nil ||
navigationController?.presentingViewController?.presentedViewController === navigationController ||
tabBarController?.presentingViewController is UITabBarController
}
For some one who's wondering, How to tell ViewController that it is being presented
if A is presenting/pushing B
Define an enum and property in B
enum ViewPresentationStyle {
case Push
case Present
}
//and write property
var vcPresentationStyle : ViewPresentationStyle = .Push //default value, considering that B is pushed
Now in A view controller, tell B if it is being presented/pushed by assigning presentationStyle
func presentBViewController() {
let bViewController = B()
bViewController.vcPresentationStyle = .Present //telling B that it is being presented
self.presentViewController(bViewController, animated: true, completion: nil)
}
Usage in B View Controller
override func viewDidLoad() {
super.viewDidLoad()
if self.vcPresentationStyle == .Present {
//is being presented
}
else {
//is being pushed
}
}
To detect your controller is pushed or not just use below code in anywhere you want:
if ([[[self.parentViewController childViewControllers] firstObject] isKindOfClass:[self class]]) {
// Not pushed
}
else {
// Pushed
}
I hope this code can help anyone...
As many folks here suggest, that "checking" methods don't work well for all cases, in my project I've come up with solution to manage that manually. The point is, we usually manage presentation on our own - this is not what happens behind the scene and we must to introspect.
DEViewController.h file:
#import <UIKit/UIKit.h>
// it is a base class for all view controllers within a project
@interface DEViewController : UIViewController
// specify a way viewcontroller, is presented by another viewcontroller
// the presented view controller should manually assign the value to it
typedef NS_ENUM(NSUInteger, SSViewControllerPresentationMethod) {
SSViewControllerPresentationMethodUnspecified = 0,
SSViewControllerPresentationMethodPush,
SSViewControllerPresentationMethodModal,
};
@property (nonatomic) SSViewControllerPresentationMethod viewControllerPresentationMethod;
// other properties/methods...
@end
The presentations now could be managed this way:
pushed on navigation stack:
// DETestViewController inherits from DEViewController
DETestViewController *vc = [DETestViewController new];
vc.viewControllerPresentationMethod = SSViewControllerPresentationMethodPush;
[self.navigationController pushViewController:vc animated:YES];
presented modally with navigation:
DETestViewController *vc = [DETestViewController new];
vc.viewControllerPresentationMethod = SSViewControllerPresentationMethodModal;
UINavigationController *nav = [[UINavigationController alloc]
initWithRootViewController:vc];
[self presentViewController:nav animated:YES completion:nil];
presented modally:
DETestViewController *vc = [DETestViewController new];
vc.viewControllerPresentationMethod = SSViewControllerPresentationMethodModal;
[self presentViewController:vc animated:YES completion:nil];
Also, in DEViewController we could add a fallback to "checking" if the aforementioned property equals to SSViewControllerPresentationMethodUnspecified:
- (BOOL)isViewControllerPushed
{
if (self.viewControllerPresentationMethod != SSViewControllerPresentationMethodUnspecified) {
return (BOOL)(self.viewControllerPresentationMethod == SSViewControllerPresentationMethodPush);
}
else {
// fallback to default determination method
return (BOOL)self.navigationController.viewControllers.count > 1;
}
}
Assuming that all viewControllers that you present modally are wrapped inside a new navigationController (which you should always do anyway), you can add this property to your VC.
private var wasPushed: Bool {
guard let vc = navigationController?.viewControllers.first where vc == self else {
return true
}
return false
}
In Swift:
Add a flag to test if it's a modal by the class type:
// MARK: - UIViewController implementation
extension UIViewController {
var isModal: Bool {
let presentingIsModal = presentingViewController != nil
let presentingIsNavigation = navigationController?.presentingViewController?.presentedViewController == navigationController
let presentingIsTabBar = tabBarController?.presentingViewController is UITabBarController
return presentingIsModal || presentingIsNavigation || presentingIsTabBar
}
}
You overlooked one method: isBeingPresented.
isBeingPresented is true when the view controller is being presented and false when being pushed.
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
if ([self isBeingPresented]) {
// being presented
} else if ([self isMovingToParentViewController]) {
// being pushed
} else {
// simply showing again because another VC was dismissed
}
}
Best ever solution ever is here.
if ((self.navigationController?.popViewController(animated: true)) == nil) {
self.dismiss(animated: true, completion: nil)
}
Check if Pop Navigation provide nil then Dismiss Controller. It can handle Pop and Dismiss vice versa.
Swift 5. Clean and simple.
if navigationController.presentingViewController != nil {
// Navigation controller is being presented modally
}
id presentedController = self.navigationController.modalViewController;
if (presentedController) {
// Some view is Presented
} else {
// Some view is Pushed
}
This will let you know if viewController is presented or pushed
self.navigationController != nil would mean it's in a navigation stack.
In order to handle the case that the current view controller is pushed while the navigation controller is presented modally, I have added some lines of code to check if the current view controller is the root controller in the navigation stack .
extension UIViewController {
var isModal: Bool {
if let index = navigationController?.viewControllers.firstIndex(of: self), index > 0 {
return false
} else if presentingViewController != nil {
return true
} else if let navigationController = navigationController, navigationController.presentingViewController?.presentedViewController == navigationController {
return true
} else if let tabBarController = tabBarController, tabBarController.presentingViewController is UITabBarController {
return true
} else {
return false
}
}
}
If you are using ios 5.0 or later than please use this code
-(BOOL)isPresented
{
if ([self isBeingPresented]) {
// being presented
return YES;
} else if ([self isMovingToParentViewController]) {
// being pushed
return NO;
} else {
// simply showing again because another VC was dismissed
return NO;
}
}
Swift 5
Here is solution that addresses the issue mentioned with previous answers, when isModal() returns true if pushed UIViewController is in a presented UINavigationController stack.
extension UIViewController {
var isModal: Bool {
if let index = navigationController?.viewControllers.firstIndex(of: self), index > 0 {
return false
} else if presentingViewController != nil {
return true
} else if navigationController?.presentingViewController?.presentedViewController == navigationController {
return true
} else if tabBarController?.presentingViewController is UITabBarController {
return true
} else {
return false
}
}
}
It does work for me so far. If some optimizations, please share.
Swift 5
This handy extension handles few more cases than previous answers. These cases are VC(view controller) is the root VC of app window, VC is added as child to parent VC. It tries to return true only if the viewcontroller is modally presented.
extension UIViewController {
/**
returns true only if the viewcontroller is presented.
*/
var isModal: Bool {
if let index = navigationController?.viewControllers.firstIndex(of: self), index > 0 {
return false
} else if presentingViewController != nil {
if let parent = parent, !(parent is UINavigationController || parent is UITabBarController) {
return false
}
return true
} else if let navController = navigationController, navController.presentingViewController?.presentedViewController == navController {
return true
} else if tabBarController?.presentingViewController is UITabBarController {
return true
}
return false
}
}
Thanks to Jonauz's answer. Again there is space for more optimizations. Please discuss about case that need to be handled in comment section.
if let navigationController = self.navigationController, navigationController.isBeingPresented {
// being presented
}else{
// being pushed
}
self.navigationController != nil would mean it's in a navigation stack.
Source: Stackoverflow.com