UITapGestureRecognizer with UIPickerView not working. Why?
class someVC: UIViewController, UITapGestureRecognizerDelegate
override func viewDidLoad() {
let tap = UITapGestureRecognizer(target: self, action: "dismissKeyboard")
self.pickerView.addGestureRecognizer(tap)
tap.delegate = self
}
func dismissKeyboard() {
textField.resignFirstResponder()
}
I solved problem by adding override getureRecognizer
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
Looks ok, could it be that there is another gesture recognizer swallowing the tap? You need to make sure your object is on the top of the view stack to ensure it gets fired. Also you set the delegate, does the delegate methods get called? or do they not fire either? If they don't then it means your tap gesture is not being touched(another gesture is taking the touch), if it does get fired, it means there is something wrong with the action(but i doubt that is the case).
Related
I am using autoScroll on an orthogonal section of the collectionView using compositional layout. I need to invalidate the autoscroll timer as soon as the user manually scrolls the section.
I could use scrollViewDidBeginDragging / scrollViewWillBeginDecelerating, but the scrollView delegates never get called on orthogonal sections.
If anyone has any workaround to detect user scroll event in this case, it will be helpful. Thank you.
After trying out several solutions, I found the best and the simplest solution. I added a UIPanGestureRecogniser to the UICollectionViewCell to listen to user pan events. In the selector, I just invalidate the timer. That's it!
Also we need to return true by overriding gestureRecognizer(_:shouldRecognizeSimultaneouslyWith:) so that the vertical scroll and horizontal scrolls works properly.
This is what I added to the UICollectionViewCell class:
class CustomCell: UICollectionViewCell {
override init(frame: CGRect) {
super.init(frame: .zero)
pan = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
pan.delegate = self
self.addGestureRecognizer(pan)
}
#objc private func handlePan(_ pan: UIPanGestureRecognizer) {
delegate?.invalidateTimer()
}
}
extension CustomCell: UIGestureRecognizerDelegate {
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
}
With this, every time the user tries to scroll, I invalidate the autoScroll timer
I am displaying a PDF file and would like to add a screen edge gesture to move pages around.
The following code works fine when entire the content of a PDF is displayed on the screen. However, when the PDF was zoomed, the screen edge gesture cannot even activate.
override func viewDidLoad(){
super.viewDidLoad()
//set up gesture to swipe from the edge
let leftScreenEdgeRecognizer = UIScreenEdgePanGestureRecognizer (
target: self, action: #selector(TextDocumentViewController.leftEdgePanGestureHandler(_ : )))
leftScreenEdgeRecognizer.edges = UIRectEdge.left
let rightScreenEdgeRecognizer = UIScreenEdgePanGestureRecognizer (
target: self, action: #selector(TextDocumentViewController.rightEdgePanGestureHandler(_ : )))
rightScreenEdgeRecognizer.edges = UIRectEdge.right
//register the gesture
pdfView.addGestureRecognizer(leftScreenEdgeRecognizer)
pdfView.addGestureRecognizer(rightScreenEdgeRecognizer)
}
//gesture functions here
#objc func leftEdgePanGestureHandler(_ sender: UIScreenEdgePanGestureRecognizer){
if(sender.state == UIGestureRecognizer.State.ended){
print ("Left Edge")
pdfView.goToPreviousPage(sender)
}
}
#objc func rightEdgePanGestureHandler(_ sender: UIScreenEdgePanGestureRecognizer){
if(sender.state == UIGestureRecognizer.State.ended){
print ("right Edge")
pdfView.goToNextPage(sender)
}
}
I tired to add a code like,
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
However, this is not working at all.
I was able to solve this problem thanks to the answer provided for my old question. I have totally forgotten about the post. After learning more about multiple gesture detections through try and error, I realized that I can do as follows to solve this posted question:
Enables the multiple gesture activation:
class ViewController: UIViewController, UIGestureRecognizerDelegate, UIDocumentPickerDelegate, PDFViewDelegate {
// ... other things
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
shouldRecognizeSimultaneouslyWith otherGestureRecognizer:
UIGestureRecognizer) -> Bool {
return true
}
}
Make sure to appropriately set delegate.
override func viewDidLoad(){
super.viewDidLoad()
//set gesture
leftScreenEdgeRecognizer.delegate = self
rightScreenEdgeRecognizer.delegate = self
}
I have this code:
extension UIViewController {
func hideKeyboardWhenTappedAround() {
let tap = UITapGestureRecognizer(target: self, action: #selector(self.dissmissKeyboard))
tap.cancelsTouchesInView = false
view.addGestureRecognizer(tap)
}
#objc func dismissKeyboard() {
view.endEditing(true)
}
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
// Don't handle button taps
return !(touch.view is UIButton)
}
This is a global function!
When I press the login button the keyboard disappears and then I must to press it again to login. Is there a way to avoid this?
I want that when I press login button keyboard not disappear but when I press outside button keybord disappear
What you are missing is the delegate.
tap.delegate = self
Since you haven't add the delegate, your
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
method will not execute.
Have a breakpoint there and see that it is execute or not. I don't think so. By adding the delegate that I mentioned earlier will do the trick.
The code will be look like below.
let tap = UITapGestureRecognizer(target: self, action: #selector(self.dissmissKeyboard))
tap.delegate = self
tap.cancelsTouchesInView = false
view.addGestureRecognizer(tap)
In the class you should implement the delegate class like below.
class ViewController: UIViewController, UIGestureRecognizerDelegate {
I am using spriteKit. I don't kwon whether this is important. I've initialized two UIGestureRecognizer to my view in didMove(toView):
let longPress = UILongPressGestureRecognizer()
longPress.minimumPressDuration = CFTimeInterval(0.0)
longPress.addTarget(self, action: #selector(self.longPressGesture(longpressGest:)))
self.view?.addGestureRecognizer(longPress)
let swipeUp = UISwipeGestureRecognizer()
swipeUp.direction = UISwipeGestureRecognizerDirection.up
swipeUp.addTarget(self, action: #selector(self.swipeUpGesture(swipe:)))
self.view?.addGestureRecognizer(swipeUp)
My Problem is that only the first gestureRecognizer is called (longpressGest). When I delete the first GestureRecognizer, the swipeGestureRecognizer does work. How can I solve this?
You need to make your Game Scene view the delegate of your gesture recognizer. You will also need implement its method shouldRecognizeSimultaneouslyWith as mentioned by xmasRights:
So in your Game scene declaration just add UIGestureRecognizerDelegate:
class GameScene: SKScene, SKPhysicsContactDelegate, UIGestureRecognizerDelegate {
And in your didMove(to view: SKView) method make set its delegate:
let longPress = UILongPressGestureRecognizer()
longPress.delegate = self
longPress.minimumPressDuration = 0
longPress.addTarget(self, action: #selector(longPressGesture))
view.addGestureRecognizer(longPress)
let swipeUp = UISwipeGestureRecognizer()
swipeUp.delegate = self
swipeUp.direction = .up
swipeUp.addTarget(self, action: #selector(swipeUpGesture))
view.addGestureRecognizer(swipeUp)
Also In Swift 4 you will need to add #objc to your methods
#objc func longPressGesture(_ longPress: UILongPressGestureRecognizer) {
print("longPressGesture")
}
#objc func swipeUpGesture(_ swipeUp: UISwipeGestureRecognizer) {
print("swipeUpGesture")
}
Don't forget also to add the method shouldRecognizeSimultaneouslyWith as already mentioned by xmasRights:
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
print("shouldRecognizeSimultaneouslyWith")
return true
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool
{
return true
}
https://developer.apple.com/documentation/uikit/touches_presses_and_gestures/coordinating_multiple_gesture_recognizers/allowing_the_simultaneous_recognition_of_multiple_gestures
You could also use the same gesture recognizer and differ between the two gesture inside of this function
i"m trying to implement a long press gesture recognizer on a WKWebView as follows:
var webView: WKWebView?
let longPressRecognizer = UILongPressGestureRecognizer()
override func loadView() {
super.loadView()
var webViewConfig: WKWebViewConfiguration = WKWebViewConfiguration()
webViewConfig.allowsInlineMediaPlayback = true
webViewConfig.mediaPlaybackRequiresUserAction = false
self.webView = WKWebView(frame: self.view.frame, configuration: webViewConfig)
self.view = self.webView!
//hook the long press event
longPressRecognizer.addTarget(self, action: "onLongPress:")
self.webView!.scrollView.addGestureRecognizer(longPressRecognizer)
}
func onLongPress(gestureRecognizer:UIGestureRecognizer){
NSLog("long press detected")
}
i don't get an error but i cant seem to make it trigger the onLongPress function.
You didn't set the delegate of the gesture recognizer.
//hook the long press event
longPressRecognizer.delegate = self
longPressRecognizer.addTarget(self, action: "onLongPress:")
self.webView!.scrollView.addGestureRecognizer(longPressRecognizer)
In case that it still doesn't work, this may probably due to WKWebView already has its own gesture recognizers. Then add the following method to your class:
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}
And in your event method check for the gesture began:
func onLongPress(gestureRecognizer:UIGestureRecognizer){
if gestureRecognizer.state == UIGestureRecognizerState.Began {
NSLog("long press detected")
}
}