I've created UIViewController with UIScrollView in it. In UIScrollView I added some UITextFields for data input. When one of the UITextFields becomes firstResponder (keyboard appeared on the screen) and I'm trying to pop this UIViewController with a swipe gesture, I have the following effect:
View of the UIViewController is getting down and I may see the part of previous UIViewController in current UIViewController. Do you have any ideas, how to solve this?
I have found out that when using custom back actions, the interactive pop gesture stops working.
To fix this you can set the interactivePopGestureRecognizer.delegate property to nil.
Try this:
class NavigationController: UINavigationController, UIGestureRecognizerDelegate {
/// Custom back buttons disable the interactive pop animation
/// To enable it back we set the recognizer to `self`
override func viewDidLoad() {
super.viewDidLoad()
interactivePopGestureRecognizer?.delegate = self
}
func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
return viewControllers.count > 1
}
}
Related
In iOS 13 modal presentations using the form and page sheet style can be dismissed with a pan down gesture. This is problematic in one of my form sheets because the user draws into this box which interferes with the gesture. It pulls the screen down instead of drawing a vertical line.
How can you disable the vertical swipe to dismiss gesture in a modal view controller presented as a sheet?
Setting isModalInPresentation = true still allows the sheet to be pulled down, it just won't dismiss.
In general, you shouldn't try to disable the swipe to dismiss functionality, as users expect all form/page sheets to behave the same across all apps. Instead, you may want to consider using a full-screen presentation style. If you do want to use a sheet that can't be dismissed via swipe, set isModalInPresentation = true, but note this still allows the sheet to be pulled down vertically and it'll bounce back up upon releasing the touch. Check out the UIAdaptivePresentationControllerDelegate documentation to react when the user tries to dismiss it via swipe, among other actions.
If you have a scenario where your app's gesture or touch handling is impacted by the swipe to dismiss feature, I did receive some advice from an Apple engineer on how to fix that.
If you can prevent the system's pan gesture recognizer from beginning, this will prevent the gestural dismissal. A few ways to do this:
If your canvas drawing is done with a gesture recognizer, such as your own UIGestureRecognizer subclass, enter the began phase before the sheet’s dismiss gesture does. If you recognize as quickly as UIPanGestureRecognizer, you will win, and the sheet’s dismiss gesture will be subverted.
If your canvas drawing is done with a gesture recognizer, setup a dynamic failure requirement with -shouldBeRequiredToFailByGestureRecognizer: (or the related delegate method), where you return NO if the passed in gesture recognizer is a UIPanGestureRecognizer.
If your canvas drawing is done with manual touch handling (e.g. touchesBegan:), override -gestureRecognizerShouldBegin on your touch handling view, and return NO if the passed in gesture recognizer is a UIPanGestureRecognizer.
With my setup #3 proved to work very well. This allows the user to swipe down anywhere outside of the drawing canvas to dismiss (like the nav bar), while allowing the user to draw without moving the sheet, just as one would expect.
I cannot recommend trying to find the gesture to disable it, as it seems to be rather dynamic and can reenable itself when switching between different size classes for example, and this could change in future releases.
This gesture can be found in the modal view controller's presentedView property. As I debugged, the gestureRecognizers array of this property has only one item and printing it resulted in something like this:
UIPanGestureRecognizer: 0x7fd3b8401aa0
(_UISheetInteractionBackgroundDismissRecognizer);
So to disable this gesture you can do like below:
let vc = UIViewController()
self.present(vc, animated: true, completion: {
vc.presentationController?.presentedView?.gestureRecognizers?[0].isEnabled = false
})
To re-enable it simply set isEnabled back to true:
vc.presentationController?.presentedView?.gestureRecognizers?[0].isEnabled = true
Note that iOS 13 is still in beta so a simpler approach might be added in an upcoming release.
Although this solution seems to work at the moment, I would not recommend it as it might not work in some situations or might be changed in future iOS releases and possibly affect your app.
Use this in the presented ViewController viewDidLoad:
if #available(iOS 13.0, *) {
self.isModalInPresentation = true
}
In my case, I have a modal screen with a view that receives touches to capture customer signatures.
Disabling the gesture recognizer in the navigation controller solved the problem, preventing the modal interactive dismissal from being triggered at all.
The following methods are implemented in our modal view controller, and are called via delegate from our custom signature view.
Called from touchesBegan:
private func disableDismissalRecognizers() {
navigationController?.presentationController?.presentedView?.gestureRecognizers?.forEach {
$0.isEnabled = false
}
}
Called from touchesEnded:
private func enableDismissalRecognizers() {
navigationController?.presentationController?.presentedView?.gestureRecognizers?.forEach {
$0.isEnabled = true
}
}
Here is a GIF showing the behavior:
This question, flagged as duplicate, describes better the issue I had: Disabling interactive dismissal of presented view controller on iOS 13 when dragging from the main view
you can change the presentation style, if its in full screen the pull down to dismiss would be disabled
navigationCont.modalPresentationStyle = .fullScreen
No need to reinvent the wheel. It is as simple as adopting the UIAdaptivePresentationControllerDelegate protocol on your destinationViewController and then implement the relevant method:
func presentationControllerShouldDismiss(_ presentationController: UIPresentationController) -> Bool {
return false
}
For example, let's suppose that your destinationViewController is prepared for segue like below:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "yourIdentifier",
let destinationVC = segue.destination as? DetailViewController
{
//do other stuff
destinationVC.presentationController?.delegate = destinationVC
}
}
Then on the destinationVC (that should adopt the protocol described above), you can implement the described method func presentationControllerShouldDismiss(_ presentationController:) -> Bool or any of the other ones, in order to handle correctly your custom behaviour.
You can use the UIAdaptivePresentationControllerDelegate method presentationControllerDidAttemptToDismiss and disable the gestureRecognizer on the presentedView.
Something like this:
func presentationControllerDidAttemptToDismiss(_ presentationController: UIPresentationController) {
presentationController.presentedView?.gestureRecognizers?.first?.isEnabled = false
}
For every body having problems with Jordans solution #3 running.
You have to look for the ROOT viewcontroller which is beeing presented, depending on your viewstack, this is maybe not you current view.
I had to look for my navigation controllers PresentationViewController.
BTW #Jordam: Thanks!
UIGestureRecognizer *gesture = [[self.navigationController.presentationController.presentedView gestureRecognizers] firstObject];
if ([gesture isKindOfClass:[UIPanGestureRecognizer class]]) {
UIPanGestureRecognizer * pan = (UIPanGestureRecognizer *)gesture;
pan.delegate = self;
}
You may first get a reference to the UIPanGestureRecognizer handling the page sheet dismissal in viewDidAppear() method. Notice that this reference is nil in viewWillAppear() or viewDidLoad(). Then you simply disable it.
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
presentationController?.presentedView?.gestureRecognizers?.first.isEnabled = false
}
If you want more customization rather than disabling it completely, for example, when using a navBar within the page sheet, set the delegate of that UIPanGestureRecognizer to your own view controller. That way, you can disable the gesture recognizer exclusively in your contentView while keeping it active in your navBar region by implementing
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {}
in IOS 13
if #available(iOS 13.0, *) {
obj.isModalInPresentation = true
} else {
// Fallback on earlier versions
}
Me, I use this :
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
for(UIGestureRecognizer *gr in self.presentationController.presentedView.gestureRecognizers) {
if (#available(iOS 11.0, *)) {
if([gr.name isEqualToString:#"_UISheetInteractionBackgroundDismissRecognizer"]) {
gr.enabled = false;
}
}
}
Will try to describe method 2 already suggested by #Jordan H in more details:
1) To be able to catch and make decisions about the modal sheet's pan gesture add this into view controller's viewDidLoad:
navigationController?.presentationController?.presentedView?.gestureRecognizers?.forEach {
$0.delegate = self
}
2) Enable the ability to catch the pan gesture together with your own gestures using gestureRecognizer(_:shouldRecognizeSimultaneouslyWith:)
3) The actual decision can go in gestureRecognizer(_:shouldBeRequiredToFailBy:)
Example code, which makes the swipe gesture to be preferred over sheet's pan gesture, if both present. It doesn't affect original pan gesture in areas where there is no swipe gesture recognizer and therefore the original "swipe to dismiss" can still work as designed.
extension PeopleViewController: UIGestureRecognizerDelegate {
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
if gestureRecognizer === UIPanGestureRecognizer.self && otherGestureRecognizer === UISwipeGestureRecognizer.self {
return true
}
return false
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
}
In my case I have only a few swipe gesture recognizers, so comparing types is enough for me, but if there more of them it might make sense to compare the gestureRecognizers themselves (either programmatically added ones or as outlets from interface builder) as described in this doc: https://developer.apple.com/documentation/uikit/touches_presses_and_gestures/coordinating_multiple_gesture_recognizers/preferring_one_gesture_over_another
Here's how the code works in my case. Without it the swipe gesture was mostly ignored and worked only occasionally.
In the case when a UITableView or UICollectionView initiates the page sheet dismiss gesture when the user attempts to scroll past the top end of the scrolling view, this gesture can be disabled by adding an invisible UIRefreshControl that calls endRefreshing immediately.
See also https://stackoverflow.com/a/58676756/2419404
SwiftUI since iOS 15
.interactiveDismissDisabled()
For Example:
.sheet(isPresented: $add) {
AddView()
.interactiveDismissDisabled()
}
For navigation Controller, to avoid swipe interaction for presented view we can use:
if #available(iOS 13.0, *) {navController.isModalInPresentation = true}
In prepare(for:sender:) :
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == viewControllerSegueID {
let controller = segue.destination as! YourViewController
controller.modalPresentationStyle = .fullScreen
}
}
or, after you initialize your controller:
let controller = YourViewController()
controller.modalPresentationStyle = .fullScreen
What's the best approach to make UINavigationBar scroll just like other elements in the UIViewController on push or swipe gesture back when using a UINavigationController ?
A UINavigationController subclass that supports pop-interactive UINavigationbar with hidden or show.
See this Library: KDInteractiveNavigationController
From iOS 8 and above, to scroll the UINavigationBar, use the following:
Swift:
class YourViewController: UITableViewController {
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
navigationController?.hidesBarsOnSwipe = true
}
}
For more details click here
My swipe to go back feature works but only works on the edge of the screen. How can I have it work from anywhere on the screen?
It's actually quite easy to do on the UINavigationController subclass without any intervention into every UIViewController subclass pushed. Also respecting built-in swipe-from-edge state (so when it's disabled intentionally, the new gesture is disabled as well):
import UIKit
class NavigationController: UINavigationController {
override func viewDidLoad() {
super.viewDidLoad()
setupFullWidthBackGesture()
}
private lazy var fullWidthBackGestureRecognizer = UIPanGestureRecognizer()
private func setupFullWidthBackGesture() {
// The trick here is to wire up our full-width `fullWidthBackGestureRecognizer` to execute the same handler as
// the system `interactivePopGestureRecognizer`. That's done by assigning the same "targets" (effectively
// object and selector) of the system one to our gesture recognizer.
guard
let interactivePopGestureRecognizer = interactivePopGestureRecognizer,
let targets = interactivePopGestureRecognizer.value(forKey: "targets")
else {
return
}
fullWidthBackGestureRecognizer.setValue(targets, forKey: "targets")
fullWidthBackGestureRecognizer.delegate = self
view.addGestureRecognizer(fullWidthBackGestureRecognizer)
}
}
extension NavigationController: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
let isSystemSwipeToBackEnabled = interactivePopGestureRecognizer?.isEnabled == true
let isThereStackedViewControllers = viewControllers.count > 1
return isSystemSwipeToBackEnabled && isThereStackedViewControllers
}
}
Apple says here :
interactivePopGestureRecognizer
The gesture recognizer responsible for popping the top view controller
off the navigation stack. (read-only)
#property(nonatomic, readonly) UIGestureRecognizer
*interactivePopGestureRecognizer
The navigation controller installs this gesture recognizer on its view
and uses it to pop the topmost view controller off the navigation
stack. You can use this property to retrieve the gesture recognizer
and tie it to the behavior of other gesture recognizers in your user
interface. When tying your gesture recognizers together, make sure
they recognize their gestures simultaneously to ensure that your
gesture recognizers are given a chance to handle the event.
So SloppySwiper library customise the UIPanGestureRecognizer.
Check out the library SloppySwiper, which achieves this by using UIPanGestureRecognizer and by recreating the default animation.
SloppySwiper:- UINavigationController delegate that allows swipe back gesture to be started from anywhere on the screen like instagram.
Usage of this library can be found here.
Cocoapods:- pod "SloppySwiper"
I test this library on ios7 and above. It works like a charm.
Swipe to go back is default behavior of pushed/showed view controllers. It works from left edge of the screen (by default). If you want to swipe back from any part of the screen, you should add UISwipeGestureRecognizer to your view:
let swipeGestureRecognizer = UISwipeGestureRecognizer(target: self, action: "didSwipe:")
self.view.addGestureRecognizer(swipeGestureRecognizer)
I have a UIViewController that gets pushed onto a navigation stack. I'd like to extend the standard iOS7 interactive pan gesture to pop this view controller beyond the default UIRectEdgeLeft boundaries, so that users can initiate an interactive back action by panning from anywhere on the view.
I've tried rolling my own interactive view controller transition, but it's a lot of hassle to fully replicate the nice parallax handling of the default interactivePopGestureRecognizer. For example, the fromViewController hides the navigation bar, while the toViewController shows it—something that is not easy to handle in a custom interactive transition, but is seamless in the default action.
As a result, I want to extend the default action to a larger area of pan gesture, but the API doesn't seem to support simply replacing the gesture.
Any creative suggestions?
Check out my library SloppySwiper, which achieves this by using UIPanGestureRecognizer and by recreating the default animation. You can also see my ideas in https://github.com/fastred/SloppySwiper/issues/1.
It's actually quite easy to do on the UINavigationController subclass without any intervention into every UIViewController subclass pushed. Also respecting built-in swipe-from-edge state (so when it's disabled for some reason, the new gesture is disabled as well):
import UIKit
class NavigationController: UINavigationController {
override func viewDidLoad() {
super.viewDidLoad()
setupFullWidthBackGesture()
}
private lazy var fullWidthBackGestureRecognizer = UIPanGestureRecognizer()
private func setupFullWidthBackGesture() {
// The trick here is to wire up our full-width `fullWidthBackGestureRecognizer` to execute the same handler as
// the system `interactivePopGestureRecognizer`. That's done by assigning the same "targets" (effectively
// object and selector) of the system one to our gesture recognizer.
guard
let interactivePopGestureRecognizer = interactivePopGestureRecognizer,
let targets = interactivePopGestureRecognizer.value(forKey: "targets")
else {
return
}
fullWidthBackGestureRecognizer.setValue(targets, forKey: "targets")
fullWidthBackGestureRecognizer.delegate = self
view.addGestureRecognizer(fullWidthBackGestureRecognizer)
}
}
extension NavigationController: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
let isSystemSwipeToBackEnabled = interactivePopGestureRecognizer?.isEnabled == true
let isThereStackedViewControllers = viewControllers.count > 1
return isSystemSwipeToBackEnabled && isThereStackedViewControllers
}
}
So I have a navigation controller in my built for iOS 7 app. The titleView is visible, as well as the back button and navigation bar its self. For some reason, the interactive pop gesture (swipe from the left edge) isn't working. Nothing happens. When I log the gesture, it is not nil. Is there anything special I have to do to enable this functionality? What could cause it not to work?
I have found that when using custom back buttons, the interactive pop gesture stops working (my take is that Apple cannot foresee how your custom back button will behave, so they disable the gesture).
To fix this, as other mentioned before, you can set the interactivePopGestureRecognizer.delegate property to nil.
In Swift, this can easily be done across your entire application by adding an extension for UINavigationController like this:
extension UINavigationController {
override public func viewDidLoad() {
super.viewDidLoad()
interactivePopGestureRecognizer?.delegate = nil
}
}
Updated answer
Seems like setting the delegate to nil causes the app UI to freeze in some scenarios (eg. when the user swipes left or right on the top view controller of the navigation stack).
Because gestureRecognizerShouldBegin delegate method cannot be handled in an extension, subclassing UINavigationController seems like the best solution:
class NavigationController: UINavigationController, UIGestureRecognizerDelegate {
/// Custom back buttons disable the interactive pop animation
/// To enable it back we set the recognizer to `self`
override func viewDidLoad() {
super.viewDidLoad()
interactivePopGestureRecognizer?.delegate = self
}
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
return viewControllers.count > 1
}
}
Eh, looks like I just had to set the gesture delegate and implement the following:
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
Look at this response and comments. All you have to do is set your navigation controller's interactive pop gesture recognizer's delegate to nil:
self.navigationController.interactivePopGestureRecognizer.delegate = nil;
Setting it to a casted self to id<UIGestureRecognizerDelegate> also works because all methods in the protocol are optional, but I think setting the delegate to nil is more appropriate in this case.
My answer is based on Eneko's answer but uses only an extension on UINavigationController and works in Swift 5:
extension UINavigationController: UIGestureRecognizerDelegate {
override open func viewDidLoad() {
super.viewDidLoad()
interactivePopGestureRecognizer?.delegate = self
}
public func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
return viewControllers.count > 1
}
}
You can put this line in the viewDidLoad method.
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;
If you feel you have tried all solutions and stretching your head then you're at the right place.
Goto simulator > Window > Enable Show Device Bezels
Now tried to simulate swipe to back gesture.
The more worked out answer was both Aaron and lojals
First Customise the Navigation controller and then put this code in the class
In ViewDidload put this line:
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;
And in class write this function
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer { return YES;}
Maybe someone may find this helpful.
If you want to hide the navigation bar but use normal swipe gestures to go back and other navigation controller features, you should use: (navigationBar)
self.navigationController?.navigationBar.isHidden = true
If you want to disable navigation bar (hide navigation bar, disable swipe for back) but want to push viewcontroller you should use: (isNavigationBarHidden)
self.navigationController?.isNavigationBarHidden = true
Update 7-DEC-2018:
Recommended way:
In case that your first controller use hidden navigation bar, but next childs use navigation bar, when you come back to base view controller you will see a black bar in transition in place of navigation bar. This will be fixed very easy if you use in first viewcontroller(parent):
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.navigationController?.setNavigationBarHidden(true, animated: animated)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
self.navigationController?.setNavigationBarHidden(false, animated: animated)
}
In Swift 4, I have a UITableView inside my view controller, I solved this issue with:
override func viewDidLoad() {
super.viewDidLoad()
self.navigationController?.interactivePopGestureRecognizer?.delegate=nil
}
Generically add interactive pop gesture to the whole app.
XCODE: 9.0, Swift: 4.0
Preferably create UINavigationController in AppDelegate.swift
Create a navigation controller
// I created a global variable, however not necessarily you will be doing this way
var nvc: UINavigationController!
implement UIGestureRecognizerDelegate
class AppDelegate: UIResponder, UIApplicationDelegate, UIGestureRecognizerDelegate {
Instantiat UINavigationController in application didFinishLaunchingWithOptions function
nvc=UINavigationController()
// For interactive pop gesture
nvc.navigationBar.isHidden=true
nvc?.interactivePopGestureRecognizer?.delegate=self
Extra step, add controller to navigation controller in application didFinishLaunchingWithOptions function
window=UIWindow()
window?.rootViewController=nvc
window?.makeKeyAndVisible()
// BaseViewController is sample controller i created with xib
nvc.pushViewController(BaseViewController(), animated: true)
Implement gusture recognizer, add below code to AppDelegate.swift
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
Note: See other post in this section for the difference between
self.navigationController?.navigationBar.isHidden=true
And
self.navigationController?.isNavigationBarHidden = true