I am trying spinning wheel concept in iOS. My base tutorial is here
UIControl is core here. Superview's userinteraction was disabled always.
So how to enable userinteraction for its subviews alone?
I have added UITapGestureRecognizer to SmallRoundViews. Gesture is not working.
If I change superview's userinteraction to enable, gesture is working. But, its not spinning.
If I change superview's userinteraction to disable, spinning is working. But gesture is not working.
I need everything to be done. Can you guide me?
Following code is working for,
If I change superview's userinteraction to true, both UITapGestureRecognizer and spinning is working..
Override UITouch method in UIControl subclass.
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch : UITouch = touches.first!
self.beginTracking(touch, with: event)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch : UITouch = touches.first!
self.continueTracking(touch, with: event)
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch : UITouch = touches.first!
self.endTracking(touch, with: event)
}
Related
I have the following hierarchy, the root view of the controller. Added two subviews, a standard UIView and a UIScrollView. The UIView is on top.
What I want to do is to receive touches on that UIView, meaning touchesBegan, touchesMoved... like this:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
print("Began")
super.touchesBegan(touches, with: event)
next?.touchesBegan(touches, with: event)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
print("Moved")
super.touchesMoved(touches, with: event)
next?.touchesMoved(touches, with: event)
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
print("Ended")
super.touchesEnded(touches, with: event)
next?.touchesEnded(touches, with: event)
}
But at the same time I want the scroll to work. The UIScrollView that is below, I want that to keep scrolling as usual.
This seems impossible to do. If my view handles touches, then I can't forward them to the UIScrollView. But I want both things: see the raw touches on the top view while the scrollview to work as usual.
How can I accomplish this?
The opposite would also work. Meaning, a scrollview on top that scrolls as usual but I also receive the raw touches (touchesBegan, touchesMoved...) on the view that is underneath.
Following this answer worked for me, though with some slight changes. Do note that for this solution, the UIScrollView is on top of the UIView. Firstly, you need to create a subclass of UIScrollView and override the touch methods.
protocol CustomScrollViewDelegate {
func scrollViewTouchBegan(_ touches: Set<UITouch>, with event: UIEvent?)
func scrollViewTouchMoved(_ touches: Set<UITouch>, with event: UIEvent?)
func scrollViewTouchEnded(_ touches: Set<UITouch>, with event: UIEvent?)
}
class CustomScrollView: UIScrollView {
var customDelegate: CustomScrollViewDelegate?
override func awakeFromNib() {
super.awakeFromNib()
for gesture in self.gestureRecognizers ?? [] {
gesture.cancelsTouchesInView = false
gesture.delaysTouchesBegan = false
gesture.delaysTouchesEnded = false
}
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
customDelegate?.scrollViewTouchBegan(touches, with: event)
super.touchesBegan(touches, with: event)
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
customDelegate?.scrollViewTouchMoved(touches, with: event)
super.touchesMoved(touches, with: event)
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
customDelegate?.scrollViewTouchEnded(touches, with: event)
super.touchesEnded(touches, with: event)
}
}
Take note of the code in awakeFromNib(). UIScrollView has its own set of gestures. So for each gesture, delaysTouchesBegan and delaysTouchesEnded needs to be false to prevent delays for the touch events.
Finally, just assign the delegate to your ViewController and implement the methods like so.
class ViewController: UIViewController {
#IBOutlet weak var scrollView: CustomScrollView!
#IBOutlet weak var touchView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
scrollView.customDelegate = self
}
}
extension ViewController: CustomScrollViewDelegate {
func scrollViewTouchBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
// Check if touch location is within the bounds of the UIView
if let touch = touches.first {
let position = touch.location(in: view)
if touchView.bounds.contains(position) {
print("Began")
}
}
}
func scrollViewTouchMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
// Check if touch location is within the bounds of the UIView
if let touch = touches.first {
let position = touch.location(in: view)
if touchView.bounds.contains(position) {
print("Moved")
}
}
}
func scrollViewTouchEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
// Check if touch location is within the bounds of the UIView
if let touch = touches.first {
let position = touch.location(in: view)
if touchView.bounds.contains(position) {
print("Ended")
}
}
}
}
What's the best way to determine whether there is any active touch happening in a view hierarchy? Something like:
view.hasTouches
returns true if view or any of its descendant has active touches.
To those who would suggest using UIResponder's touch event handling API like touchesBegan, notice that view doesn't receive these calls if one of its descendant is handling the touch events.
You can use touchesBegan and touchesEnded methods in UIViewController as follows:
class ViewController: UIViewController {
var isTouching = false
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
isTouching = true
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
isTouching = false
}
}
I am making a "slide to confirm" button, the set up is a custom UIButton + a regular UIImageView, the image is passed to the button and the button listen to touches and move the image accordingly.
Everything is working great except for one detail after the button is released everything should go back to their initial state, yet the button stay changed as if its alpha was halved
i commented the alpha because the button was going to hide but i disabled that once i run into this problem, the problem happens regardless of setting the alpha or not.
This is the code for the custom button
class SlideButton: UIButton {
var arrowImage: UIImageView?
var initialLocation: CGPoint?
var initialArrowPosition: CGPoint?
func setArrow(arrow:UIImageView){
arrowImage = arrow
initialArrowPosition = arrow.frame.origin
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
let touch = touches.first!
let location = touch.location(in: self.superview)
initialLocation = location
UIView.animate(withDuration: 0.2) {
//self.alpha = 0.0
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
UIView.animate(withDuration: 0.3) {
self.arrowImage!.frame.origin = self.initialArrowPosition!
//self.alpha = 1.0
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch = touches.first!
let currentLocation = touch.location(in: self.superview)
arrowImage!.frame.origin.x = initialArrowPosition!.x - initialLocation!.x + (currentLocation.x)
}
}
You are remembering to call super for one of your touches methods:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
But for the other touches methods you've forgotten to do that, so you've broken the core functionality of the button.
you might have to also add an override to touchesCancelled because you might not always hit the touchesEnded endpoint.
I want to change the color of a UIView based on the number of touches currently on it. I have managed to create this with a single touch:
class colorChangerViewClass: UIView {
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
setColor(color: .blue)
print("touchesBegan")
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
setColor(color: .green)
print("touchesEnded")
}
func setColor(color: UIColor) {
self.backgroundColor = color
}
}
But I am struggling with implementing multitouch. I feel like I'm not understanding something here.
Does UIView have a property to check how many fingers are currently touching it?
I could check that each time a new touchesBegan or touchesEnded occurs.
First enable multi touch on your subclass
self.isMultipleTouchEnabled = true
Then inside your touch event functions you can get all touches with event from your UIView class.
let touchCount = event?.touches(for: self)?.count
Make sure the UIView has isMultipleTouchEnabled = true, the default is false.
Then change the touchesBegan method
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
setColor(color: .blue)
let touchCount = event?.touches(for: self)?.count
}
I really need touchesMoved(...) method in UIScrollView. I know that there is a method scrollViewDidScroll(...), but I really need the other method.
So I create subclass of UIScrollView and implement those methods.
class MyScrollView: UIScrollView {
...
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesMoved(touches, with: event)
print("Move")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
print("Touch")
}
}
If I click on the scroll view I get (let say I click two times) :
Touch
Touch
If I click on scroll view and wait a second and then move my finger I get :
Touch
Move
Move
But then scroller start to scroll and I don't receive anything anymore.
Why scroll gesture doesn't call those methods?
How do I persuade scroll view to call those methods on scroll?