I have an app that manipulates view with gestures. View is connected to pan, pinch and rotate gestures. If I start interacting with the view with two fingers all gestures are working simultaneously (expected behavior). But if you start with one finger pan, pinch and rotate gestures do not work. None of the methods in the delegate are called when I am trying to start pinch or rotate while panning.
shouldRecognizeSimultaneouslyWith
is always true.
Expected behavior,
one finger pan on the view
add second finger and start pinch/rotate interaction
(similar to instagram stories editor)
From a clean project I added the following:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
view.addGestureRecognizer({
let gesture = UIPanGestureRecognizer(target: self, action: #selector(onPan))
gesture.delegate = self
return gesture
}())
view.addGestureRecognizer({
let gesture = UIPinchGestureRecognizer(target: self, action: #selector(onPinch))
gesture.delegate = self
return gesture
}())
view.addGestureRecognizer({
let gesture = UIRotationGestureRecognizer(target: self, action: #selector(onRotate))
gesture.delegate = self
return gesture
}())
}
#objc private func onPan(_ sender: UIPanGestureRecognizer) {
print("Did pan to \(sender.translation(in: sender.view))")
}
#objc private func onPinch(_ sender: UIPinchGestureRecognizer) {
print("Did pinch to \(sender.scale)")
}
#objc private func onRotate(_ sender: UIRotationGestureRecognizer) {
print("Did rotate to: \(sender.rotation)")
}
}
extension ViewController: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool { true }
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool { true }
}
All 3 methods report changes after the scenario you described:
I started with single touch drag gesture
I pressed another finger and started rotating gesture and pinching gesture
Does already this example not work for you? What is the behavior you are experiencing and what is expected behavior?
Related
First of all, none of the already answered questions didn't help me
Swift: Long Press Gesture Recognizer - Detect taps and Long Press
Using tap gesture and long press at the same time in Table View
Long Press Gesture Recognizer Only Fired When Finger is Lifted
And so on
The code working almost fine except one thing: the long press gesture only called when I lift my finger up from the screen. But I need to get behaviour like in Instagram Stories (when you can switch between stories and hold your finger to pause pause some story).
My question is more about how to force UILongPressGesture to fire when user touch finger down, but not up.
Here's my code:
private func setupTapGestures() {
tapRecognizer = UITapGestureRecognizer()
tapRecognizer?.addTarget(self, action: #selector(handleTapGesture(_:)))
tapRecognizer?.delegate = self
view.addGestureRecognizer(tapRecognizer!)
longPressRecognizer = UILongPressGestureRecognizer()
longPressRecognizer?.addTarget(self, action: #selector(handleLongPressGesture(_:)))
longPressRecognizer?.minimumPressDuration = 0.1
longPressRecognizer?.delegate = self
view.addGestureRecognizer(longPressRecognizer!)
}
#objc func handleTapGesture(_ gestureRecognizer: UIGestureRecognizer) {
let width = view.frame.width
let point = gestureRecognizer.location(in: view)
viewModel?.tapAction(viewWidth: width, tapPoint: point)
Swift.print("Tap gesture")
}
#objc func handleLongPressGesture(_ gestureRecognizer: UILongPressGestureRecognizer) {
if gestureRecognizer.state == .began {
Swift.print("Began")
} else if gestureRecognizer.state == .ended {
Swift.print("Ended")
}
}
UIGestureRecognizerDelegate:
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
// Don't recognize a single tap until a long-press fails
if gestureRecognizer == tapRecognizer && otherGestureRecognizer == longPressRecognizer {
return true
}
return false
}
shouldRequireFailureOf docs
Any suggestions or ideas?
I wonder if your implementation of shouldRequireFailureOf is causing an issue?
This works just fine for me (note: I used .minimumPressDuration = 0.25 because it's a little difficult to tap in under 0.1 seconds):
class GestureTestViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
setupTapGestures()
}
private func setupTapGestures() -> Void {
let singleTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTapGesture(_:)))
view.addGestureRecognizer(singleTapGesture)
let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPressGesture(_:)))
longPressGesture.minimumPressDuration = 0.25
view.addGestureRecognizer(longPressGesture)
}
#objc func handleLongPressGesture(_ gesture: UILongPressGestureRecognizer) -> Void {
if gesture.state == .began {
print("Did Long Press (began)")
}
if gesture.state == .ended {
print("Did Long Press (ended)")
}
}
#objc func handleTapGesture(_ gesture: UITapGestureRecognizer) -> Void {
print("Did Single Tap")
}
}
When I tap, I get "Did Single Tap" in the debug console.
When I tap and hold, I quickly get "Did Long Press (began)", and on finger-lift I get "Did Long Press (ended)"
I have one main view and 4 subviews of the mainview they all have their UITapGestureRecognizer, when I tap on one subview how can it be triggered both views. Example below,
if I tap to subview 1 desired log would be:
subview1 is clicked
MainView is clicked
My Code
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let mainGesture = UITapGestureRecognizer(target: self, action: #selector(mainGestureActivated))
self.view.addGestureRecognizer(mainGesture)
let subGesture = UITapGestureRecognizer(target: self, action: #selector(subViewGestureActivated))
self.subview1.addGestureRecognizer(subGesture)
}
#objc func mainGestureActivated(){
print("MainView Clicked")
}
#objc func subViewGestureActivated(){
print("Subview Clicked")
}
it prints only subview clicked! Is it possible to trigger both gestureRecognizers since main is encapsulating other.
First you should conform to UIGestureRecognizerDelegate in your VC, and then implement the delegate func of shouldRecognizeSimultaneouslyWith. Inside the function, you should detect if the gestureRecognizer, and the otherGestureRecognizer are the wants you want, and if so, you should allow them to work simultaneously,
Conform to delegate, and Declare gesture recognizers outside of viewDidLoad (because you need to access them in the delegate method later.)
var mainGestureRecognizer = UITapGestureRecognizer()
var subGestureRecognizer = UITapGestureRecognizer()
Initialize your recognizers, and set your VC as their delegate:
mainGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(mainGestureActivated))
subGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(subViewGestureActivated))
mainGestureRecognizer.delegate = self
subGestureRecognizer.delegate = self
Implement the delegate function mentioned above to allow simultaneous recognition for subView and mainView:
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
if gestureRecognizer == subGestureRecognizer && otherGestureRecognizer == mainGestureRecognizer {
return true
}
return false
}
And if you want it to work for 4 different subviews, then you should check with else if statements inside the delegate method.
I am using both a tap and pan gesture in my View. The view has a UICollectionView where I am trying to call didSelectItemAthowever the method is not called.
I have tried the following, but with no luck.
override func viewDidLoad() {
panGesture.delegate = self
tapGesture.delegate = self
}
extension AddNotebookViewController: UIGestureRecognizerDelegate {
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
}
Does anybody have any idea what the issue may be ?
The problem, as you've already guessed, is that the background view's gesture recognizer swallows the tap that would select the collection view cell. To solve the problem, implement this gesture recognizer delegate method in your view controller:
func gestureRecognizerShouldBegin(_ gr: UIGestureRecognizer) -> Bool {
let p = gr.location(in: self.view)
let v = self.view.hitTest(p, with: nil)
return v == gr.view
}
The result is that if the gesture is in the collection view, the background view's gesture recognizer won't begin and normal selection will be able to take place.
I want to customize my long press gesture recognizer in the following ways:
1) When I hold down on an object for 0.5 seconds, the object darkens, and
2) When I continue to hold down on the object for another second (total of 1.5 seconds), some action happens (e.g. the object disappears).
Essentially, by holding down on an object for a minimum of 1.5 seconds, two actions happened at two separate times. I also have a tap gesture recognizer, which might affect things.
The answer from #nathan is essentially fine but a detail is missing you need to implement the UIGestureRecognizerDelegate to allow both gestures works simultaneously, so this is my code
class ViewController: UIViewController, UIGestureRecognizerDelegate{
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
//this for .5 time
let firstGesture = UILongPressGestureRecognizer(target: self, action: #selector(firstMethod))
//this for 1.5
let secondGesture = UILongPressGestureRecognizer(target: self, action: #selector(secondMethod))
secondGesture.minimumPressDuration = 1.5
firstGesture.delegate = self
secondGesture.delegate = self
self.view.addGestureRecognizer(firstGesture)
self.view.addGestureRecognizer(secondGesture)
}
func firstMethod() {
debugPrint("short")
}
func secondMethod() {
debugPrint("long")
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool{
return true
}
}
Hope this help
See Reinier's solution as it's the correct one. This one adds a delay to satisfy require(toFail:)
You can set the timing using the property minimumPressDuration (in seconds, default is 0.5)
let quickActionPress = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.zeroFiveSecondPress(gesture:))) // 0.5 seconds by default
let laterActionPress = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.oneFiveSecondPress(gesture:)))
laterActionPress.minimumPressDuration = 1.5
someView.addGestureRecognizer(quickActionPress)
someView.addGestureRecognizer(laterActionPress)
// If 1.5 detected, only execute that one
quickActionPress.require(toFail: laterActionPress)
#objc func zeroFiveSecondPress(gesture: UIGestureRecognizer) {
// Do something
print("0.5 press")
}
#objc func oneFiveSecondPress(gesture: UIGestureRecognizer) {
zeroFiveSecondPress(gesture: gesture)
// Do something else
print("1.5 press")
}
In my ViewController I have a UIScreenEdgeGestureRecognizer for switching views but also a UITableView with a custom UITableViewCell. In this custom UITableViewCell is a UIPanGestureRecognizer for swiping the cells.
I added gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: so both of the gestures are working and gestureRecognizerShouldBegin to prevent the conflict of vertical scrolling.
The question is, how can I give the UIScreenEdgeGestureRecognizer priority? When I swipe at the edge of the screen, I want to switch the views without panning the cells. I figured I should be using the delegate methods, but so far the more I read the more confused I'm getting.
Code in custom UITableViewCell:
override func viewDidload() {
var recognizer = UIPanGestureRecognizer(target: self, action: "handlePan:")
recognizer.delegate = self
addGestureRecognizer(recognizer)
}
override func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
override func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
if let panGesture = gestureRecognizer as? UIPanGestureRecognizer {
let velocity = panGesture.velocityInView(superview!)
if fabs(velocity.x) > fabs(velocity.y) { return true }
return false
}
return false
}
ViewController:
override func viewDidLoad() {
let rightScreenEdgeRecognizer = EdgePanGesture(target: self, action: "changeView:")
rightScreenEdgeRecognizer.edges = .Right
view.addGestureRecognizer(rightScreenEdgeRecognizer)
}
I also tried identifying the recognizers with:
gestureRecognizer.isKindOfClass(UIScreenEdgePanGestureRecognizer)
and
gestureRecognizer as? UIScreenEdgePanGestureRecognizer
But all were failed.
Turns out I was looking at the right direction with gestureRecognizer as? UIScreenEdgePanGestureRecognizer but instead of gestureRecognizer I should have used otherGestureRecognizer.
override func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOfGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
if let recognizer = otherGestureRecognizer as? UIScreenEdgePanGestureRecognizer {
return true
}
return false
}