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
I have a UIViewController that I show as a modalPresentationStyle = .overCurrentContext.
This over-the-context view (self.view) has backgroundColor = .clear and a subview called content.
content is full bounds width and half bounds height with a white background.
I've added UITapGestureRecognizer to self.view but I cannot tell to not fire the tap action when tapping the overlapping view (content).
Any idea on how to only trigger the action when the user taps on the view, not on the subview?
You need to conform to UIGestureRecognizerDelegate and then implement shouldReceive touch delegate method:
extension ViewController: UIGestureRecognizerDelegate {
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
if let touchView = touch.view {
if touchView.isDescendant(of: view) {
return false
}
}
return true
}
}
So if the touch area is the subView, then the tap gesture will be ignored.
I have a UITableView with static cells and grouped style in my UIViewController. I added a UIGestureRecognizer, that I can dismiss the Keyboard, but I want to except the UIGestureRecognizer for several UITableViewCells, because they have a functionality when they get selected.
My code:
The class - variable that I can use it everywhere in the code:
var tap:UITapGestureRecognizer = UITapGestureRecognizer()
My viewDidLoad() Method:
override func viewDidLoad() {
super.viewDidLoad()
self.tap = UITapGestureRecognizer(target: self, action: "DismissKeyboard")
tableView.addGestureRecognizer(tap)
}
And the Action of the UIGestureRecognizer:
func DismissKeyboard()
{
print("is here")
if(self.keyboardIsVisible)
{
view.endEditing(true)
self.refreshTableView()
}
}
I removed the Gesture Recognizer of one cell in the override func cellForRowAtIndexPath:
cell.removeGestureRecognizer(self.tap)
But when I tap this cell it still goes into the DismissKeyboard - Action...
You add your UITapGesgureRecognizer to tableView and you try remove from de cell. Try use tableView.removeGestureRecognizer(self.tap)
Instead of Adding Tap Gesture on TableView Cell or TableView. you can Add Custom UIButton on UITableViewCell and Add Target to it. You can then disable Table view's didSelectRowatIndexPath event. You can write your code on button click events.
In my SecondViewController I have a UITableView with a custom UITableViewCell where I have a UIPanGestureRecognizer and I want it to fail when otherGestureRecognizer is a UIPanGestureRecognizer from ViewController FirstViewController
The UIPanGestureRecognizer of the the cell is set to self and I tried using gestureRecognizer: shouldRequireFailureOfGestureRecognizer:
override func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOfGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
let view = otherGestureRecognizer.view
if let view as? FirstViewController.view { // Obviously doesn't work
return true
}
return false
}
The question is, how can I fail the UIPanGestureRecognizer of the UITableViewCell when a gesture has been recognized from FirstViewController?
This may seem silly, but it seems to me your problem is purely one of identification: Is this gesture recognizer, otherGestureRecognizer, the particular gesture recognizer I'm worried about and am supposed to yield to? What occurs to me immediately are two choices:
You have, as you rightly point out, its view. Are there no questions you can ask about this view that would help you identify it? Has it a distinguishing backgroundColor or any other feature that would help here? What about its class? Is it a plain vanilla UIView, or is it of some distinguishing class?
You also have the UIPanGestureRecognizer itself. So a drop-dead simple solution, which is what I'd probably use, is to subclass UIPanGestureRecognizer: let's call the subclass MySpecialPanGestureRecognizer. This subclass has no special functionality, and no purpose except to act as an identifier! When you give the view its gesture recognizer, make that gesture recognizer a MySpecialPanGestureRecognizer. Now you can ask whether otherGestureRecognizer is MySpecialPanGestureRecognizer.
I'm trying to make a simple swipe up gesture, I dragged the Swipe Gesture Recogniser over a UIImage, I then Ctrl button drag the Swipe Gesture to my swift file and create the following Action: -
#IBAction func swipeDice(sender: UISwipeGestureRecognizer) {
//Test display
testLabel.text = "Zing"
}
The app builds and runs successfully however when I test the swipe gesture it doesn't seem to do anything.
Is that all the code I need for the gesture to run?
How do I make it recognise a 2 finger swipe gesture?
You need to enable User Interaction for the UIImage that you added the UIGestureRecognier to:
Open the Attributes Inspector for the UIImage and tick User Interaction Enabled:
If you created the Swipe Gesture Recognizer in IB you can setup the gesture through the right window.
If you have a conflict between several gestures you can handle this through the UIGestureRecognizerDelegate protocol.
Add the following function to your code:
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}