Created
July 28, 2019 07:06
-
-
Save ppth0608/8307aed49cd2f0ba5b4600e6120853f4 to your computer and use it in GitHub Desktop.
How to add gestureRecognizer like Instagram pinch+pan gesture
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import UIKit | |
public class ISImageView: UIImageView { | |
@IBInspectable public var isInteractable: Bool = false { | |
didSet { | |
guard oldValue != isInteractable else { return } | |
if isInteractable { | |
setupGesture() | |
cellForTarget(superview: superview)?.clipsToBounds = false | |
isUserInteractionEnabled = true | |
pinchGesture.map { addGestureRecognizer($0) } | |
panGesture.map { addGestureRecognizer($0) } | |
} else { | |
pinchGesture.map { removeGestureRecognizer($0) } | |
panGesture.map { removeGestureRecognizer($0) } | |
} | |
} | |
} | |
private var isPinching = false | |
private var pinchGesture: UIPinchGestureRecognizer? | |
private var panGesture: UIPanGestureRecognizer? | |
private var originalCenter: CGPoint? | |
private func setupGesture() { | |
pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinchGesture(sender:))) | |
pinchGesture?.delegate = self | |
panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePanGesture(sender:))) | |
panGesture?.delegate = self | |
} | |
private func cellForTarget(superview: UIView?) -> UIView? { | |
guard superview != nil else { | |
return nil | |
} | |
if superview is UITableViewCell || superview is UICollectionViewCell { | |
return superview | |
} else { | |
return cellForTarget(superview: superview?.superview) | |
} | |
} | |
@objc private func handlePinchGesture(sender: UIPinchGestureRecognizer) { | |
switch sender.state { | |
case .began: | |
isPinching = sender.scale > 1 | |
layer.zPosition = 1 | |
cellForTarget(superview: superview)?.layer.zPosition = 1 | |
case .changed: | |
guard let view = sender.view, isPinching else { return } | |
let center = CGPoint(x: sender.location(in: view).x - view.bounds.midX, | |
y: sender.location(in: view).y - view.bounds.midY) | |
view.transform = view.transform | |
.translatedBy(x: center.x, y: center.y) | |
.scaledBy(x: sender.scale, y: sender.scale) | |
.translatedBy(x: -center.x, y: -center.y) | |
sender.scale = 1 | |
case .ended, .cancelled, .failed: | |
reset() | |
default: | |
break | |
} | |
} | |
@objc private func handlePanGesture(sender: UIPanGestureRecognizer) { | |
switch sender.state { | |
case .began where isPinching: | |
originalCenter = sender.view?.center | |
case .changed where isPinching: | |
guard let view = sender.view else { return } | |
let translation = sender.translation(in: self) | |
view.center = CGPoint(x:view.center.x + translation.x, y:view.center.y + translation.y) | |
sender.setTranslation(.zero, in: superview) | |
default: | |
break | |
} | |
} | |
private func reset() { | |
UIView.animate(withDuration: 0.3, animations: { | |
self.transform = .identity | |
self.center = self.originalCenter ?? self.center | |
}) { _ in | |
self.isPinching = false | |
self.layer.zPosition = 0 | |
self.cellForTarget(superview: self.superview)?.layer.zPosition = 0 | |
} | |
} | |
} | |
extension ISImageView: UIGestureRecognizerDelegate { | |
public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool { | |
if gestureRecognizer == pinchGesture && otherGestureRecognizer.view is UIScrollView { | |
return false | |
} | |
if gestureRecognizer == panGesture && otherGestureRecognizer.view is UIScrollView { | |
return true | |
} | |
return true | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment