I am a beginner in Swift, and am trying to add a swipe gesture recognizer to my UIView. I have inserted a gradient CALayer to index 0 to have a gradient background.
My problem is:
Swipe gestures for right and left work fine, but for Down it doesn't work, why?
Set the delegate of swipe gestures that you are adding to the view.
let swipeGesture = UISwipeGestureRecognizer(target: self, action: Selector("handleSwipe:"))
swipeGesture.delegate = self
self.view.addGestureRecognizer(swipeGesture)
self.mySwipeGesture = swipeGesture
GestureRecognizerDelegate asks if two gesture recognizers should be allowed to recognize gestures simultaneously. Return true to allow both gestureRecognizer and otherGestureRecognizer to recognize their gestures simultaneously. The default implementation returns false—no two gestures can be recognized simultaneously. Implement the following delegate to achieve this.
extension ViewController : UIGestureRecognizerDelegate {
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
//Identify gesture recognizer and return true else false.
return gestureRecognizer.isEqual(self.mySwipeGesture) ? true : false
}
}
Swiping Up & Down are the default property of table view. I would suggest you to disable the scrolling of the table view whenever you want to do something on the overlay.
tableView.scrollEnabled = NO;
If you are performing dragging of a particular cell then long press on it and then start dragging.
This is how you can achieve this.
Hope this helps.
Related
I have the following case. parentView has it's own gestureRecognizerAand has a subview subView which has it's own UITapGestureRecognizer.
Is there any way to tell parentView that it should pass the touch events recognized in gestureRecognizerA to subView if these touch events are in subView's bounds?
gestureRecognizerA is very specific. It is a custom gesture recognizer for recognizing a circlular motion. This recognition should happen on all areas of parentView. However, when that same gesture recognizer recognizes a tap, it should pass that tap to subView.
You can easily identify the points of tap.
As for example you have a tap gesture in parent class as:
let tapGR = UITapGestureRecognizer(target: self, action: #selector(tapped))
view.addGestureRecognizer(tapGR)
#objc func tapped(gr:UITapGestureRecognizer) {
let loc:CGPoint = gr.location(in: gr.view)
//insert your touch based code here
}
Inside the tapped method you can identify the location where tap happened, so after checking bounds of the subview with location of tap you can verify is the tap happened inside the bounds of subview or not.
It seems like you just want both of those gesture recognizers to work simultaneously. Just implement UIGestureRecognizerDelegate for your parentView and make it tapGestureRecognizer's and gestureRecognizerA's delegate. Then implement an optional method there:
// MARK: - UIGestureRecognizerDelegate
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) {
return true
}
That might be able to detect a tap in subView even while doing a circular motion within parentView.
UPDATE: When using gesture recognizers, "forwarding touches" would be to simply calling a method of another recognizer. Just put a recognizer which is doing the forwarding as its parameter.
For instance, tapGestureRecognizer fires viewWasTapped(_ sender: UITapGestureRecognizer) when a tap is detected. Now, when your gestureRecognizerA wants to forward its events to tapGestureRecognizer, it simply does so by calling:
subView.viewWasTapped(self.gestureRecognizerA)
With an obvious change to the method itself:
func viewWasTapped(_ sender: UIGestureRecognizer) {
// ...
}
This works for UITapGestureRecognizer. The sender can be any other UIGestureRecognizer and you'd still have almost all the information to resolve a tap gesture there.
I have a UIView within a UIScrollView. I want the view to do something when a tap on it begins, and do something different when the tap ends. Therefor I used a UILongPressGestureRecognizer. I set the minimumPressDuration to zero. This works fine, but my problem is that I can't use the scroll view properly anymore because every touch within the view now fires the gesture recognizer.
Has anyone an idea how to solve this?
Can I tell the LongPressGestureRecognizer not to react on swipe gestures?
Have you tried setting:
let gesture = UILongPressGestureRecognizer()
gesture.cancelsTouchesInView = false
Also try using a UILongPressGestureRecogniser with:
extension ViewController: UIGestureRecognizerDelegate {
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
}
Where ViewController is the delegate of your gesture recogniser.
The goal is to implement two pan gestures against the same SCNScene: one with one finger and the other with two fingers.
This code below isn't working. The one-finger pan function never gets invoked even though the gesture is assigned a distinct selector. One-finger pans and two-finger pans both invoke sceneViewPannedTwoFingers.
From reading other questions it seemed like shouldRecognizeSimultaneouslyWithGestureRecognizer might be the answer, but these pans are not happening simultaneously. It should be either a one-finger pan or a two-finger pan, never both at once.
Is it possible to have two pan gestures as described above? If so, what's the right way to do this?
// Handle one-finger pans
let panRecognizer = UIPanGestureRecognizer(target: self, action: #selector(sceneViewPannedOneFinger))
sceneView.addGestureRecognizer(panRecognizer)
// Handle two-finger pans
let twoFingerPanRecognizer = UIPanGestureRecognizer(target: self, action: #selector(sceneViewPannedTwoFingers))
sceneView.addGestureRecognizer(twoFingerPanRecognizer)
func sceneViewPannedTwoFingers(sender: UIPanGestureRecognizer) {
print("two finger pan!!!")
}
func sceneViewPannedOneFinger(sender: UIPanGestureRecognizer) {
print("one finger pan!!!")
}
You need to add UIGestureRecognizerDelegate to your view controller and set the gesture recognizers delegate to self inside your view controller. Add the shouldRecognizeSimultaneouslyWithGestureRecognizer method returning true for them. Make sure you set minimum and maximum number of touches also for them.
code like this
class MyClass : UIGestureRecognizerDelegate --< Delegate
func gestureRecognizer(_: UIGestureRecognizer,
shouldRecognizeSimultaneouslyWithGestureRecognizer:UIGestureRecognizer) -> Bool
{
return true
}
I have a collection view of bars that can slide up and down. Each cell in the collection view is using a UIPanGestureRecognizer to control the blue bar sliding up and down. The collection view does not scroll here.
There is an "edit mode" which disables the pan gesture controlling the bars. The hope here is that in "edit mode", the collection view can then scroll left and right.
My attempt at doing this was to disabled the pan gesture in each of the cells. I also tried using the UIGestureRecognizerDelegate methods to try to disable touches and fail the cell's pan gesture in favor of the collection view's pan gesture. It seems that the collection view's pan gesture is not forwarded to any of the cell's gesture delegate calls.
These delegate calls got me the closest (delegate for cell's pan gesture):
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
return !self.editMode // bar doesn't need to pan in edit mode
}
With this implemented, I could pan the collection view if I started the pan in the white space between cells. Starting a pan on a cell would not do anything, though.
EDIT: I uploaded a sample project of the issue to github.
If I understand this correctly, I think the problem could be as follows:
Your UICollectionView will listen for pan gestures. So far so good.
In KBHBarSlider you add UIPanGestureRecognizer for you sliders. They have "priority" over the underlaying UICollectionView.
This actually makes sense as your BarSliders are above the CollectionView. My best take would be to let the BarSliders add the UIPanGestureRecognizer when needed, and have them completely removed when editing.
So first try and remove the gestureRecognizer you added in VOLBarSliderCell.
Then in KBHBarSlider add something like: (and make sure your init calls addPanRecognizer() instead of setup())
func addPanRecognizer() {
let panGesture = UIPanGestureRecognizer(target: self, action: "viewDidPan:")
self.gestureRecognizers = [panGesture]
}
func removePanRecognizer() {
self.gestureRecognizers = []
}
It is now possible to add and remove the gestures on demand, do so from your edit get/set overrides in VOLBarSliderCell:
var editing: Bool = false {
didSet {
if !self.editing {
self.barSlider.addPanRecognizer()
// Removed code, to keep this example short...
} else {
self.barSlider.removePanRecognizer()
// Removed code, to keep this example short...
}
}
}
Try adding this code at VOLBarSliderCell:29:
self.panGesture.enabled = !self.editing
And remove:
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
if self.editing && gestureRecognizer == self.panGesture {
return false
}
return true
}
To be fair your problem was not clear to me, so I gave a try as an answer anyway since I cannot comment yet to request clarifications.
I understood you wanna scroll your UICollectionView while you are in edit mode. So that's what the code above does. If you wish to disable scrolling altogether UICollectionView while NOT editing then you can use scrollEnabled = false on the UICollectionView.
Clarify a bit better what is the problem you are trying to solve. That way you might be able to bring precise answers.
You're on the right track. Keep a reference to your leftRight gestureRecognizer. Then in shouldReceiveTouch, check if editing and the gestureRecognizer is your leftRight recognizer
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
if(self.editing && gestureRecognizer != self.leftRightRecognizer){
return 0;
}
return 1;
}
My app has a table view (with a scroll-into of course) and this view slides on and off with a gesture recognizer (like on the Facebook app).
If I use a button to slide [the table view onto the screen], it works fine but when I use a gesture recognizer, the table view can't be scrolled anymore.
Here is the code of gesture recognizer with the problem:
[self.view addGestureRecognizer:self.slidingViewController.panGesture];
Somebody have an idea?
Your gesture is probably preventing the scroll view gesture from working because by default only 1 gesture can be recognising at a time. Try adding yourself as the delegate of your gesture and implementing:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
self.slidingViewController.panGesture.delegate = self;
also, add <UIGestureRecognizerDelegate> to the list of protocols you implement
I have used UIPangesture in my UItableview and to avoid this gesture I have used below delegate,
//This method helped me stopped up/down pangesture of UITableviewCell and allow only vertical scroll
override func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
if let panGestureRecognizer = gestureRecognizer as? UIPanGestureRecognizer {
let translation = panGestureRecognizer.translationInView(superview)
if fabs(translation.x) > fabs(translation.y) {
return true
}
return false
}
return false
}
Here is the swift version:
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
I had same issue of defining long press gesture on table view and not being able to scroll table when I long press on it.
Fixed by:
1- adding
UIGestureRecognizerDelegate
2- adding
gesture.delegate = self (after you defined the long press gesture)
3- adding this function:
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {return true}
If I get it right the view that you're adding the gesture recognizer to is the table view. By default the UIScrollView (and implicitly UITableView) class uses the pan gesture recognizer for the scroll and your gesture recognizer interferes with that. If you use another view as a container for the table view and you're adding the pan gesture recognizer to it should work.