是否可以检测触摸并从当前用作3D Touch的UIViewController
视图控制器的previewingContext
获取触摸位置? (当触摸从左向右移动时,我想更改预览控制器内的图像)
我已经尝试了touchesBegan
和touchesMoved
,但没有一个被解雇。
class ThreeDTouchPreviewController: UIViewController {
func getLocationFromTouch(touches: Set<UITouch>) -> CGPoint?{
guard let touch = touches.first else { return nil }
return touch.location(in: self.view)
}
//Not fired
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let location = getLocationFromTouch(touches: touches)
print("LOCATION", location)
}
//Not fired
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
let location = getLocationFromTouch(touches: touches)
print("LOCATION", location)
}
}
甚至尝试添加UIPanGesture。
尝试复制FaceBook的3D Touch功能,用户可以从左向右移动手指以更改当前显示的图像。 上下文视频:https://streamable.com/ilnln
答案 0 :(得分:6)
如果您希望获得与FaceBook的3D Touch功能相同的结果,您需要创建自己的3D Touch gesture class
import UIKit.UIGestureRecognizerSubclass
class ForceTouchGestureRecognizer: UIGestureRecognizer {
var forceValue: CGFloat = 0
var isForceTouch: Bool = false
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
super.touchesBegan(touches, with: event)
handleForceWithTouches(touches: touches)
state = .began
self.isForceTouch = false
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
super.touchesMoved(touches, with: event)
handleForceWithTouches(touches: touches)
if self.forceValue > 6.0 {
state = .changed
self.isForceTouch = true
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
super.touchesEnded(touches, with: event)
state = .ended
handleForceWithTouches(touches: touches)
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent) {
super.touchesCancelled(touches, with: event)
state = .cancelled
handleForceWithTouches(touches: touches)
}
func handleForceWithTouches(touches: Set<UITouch>) {
if touches.count != 1 {
state = .failed
return
}
guard let touch = touches.first else {
state = .failed
return
}
forceValue = touch.force
}
}
现在您可以在ViewController
方法
viewDidLoad
添加此手势
override func viewDidLoad() {
super.viewDidLoad()
let gesture = ForceTouchGestureRecognizer(target: self, action: #selector(imagePressed(sender:)))
self.view.addGestureRecognizer(gesture)
}
现在,您可以在Storyboard中管理控制器UI。在cover view
和UICollectionView
上方添加UIImageView
,然后在代码中将其与IBOutlets
相关联。
现在您可以为手势添加处理程序方法
func imagePressed(sender:ForceTouchGestureRecognizer){
let location = sender.location(in: self.view)
guard let indexPath = collectionView?.indexPathForItem(
at: location) else { return }
让image = self.images [indexPath.row]
switch sender.state {
case .changed:
if sender.isForceTouch {
self.coverView?.isHidden = false
self.selectedImageView?.isHidden = false
self.selectedImageView?.image = image
}
case .ended:
print("force: \(sender.forceValue)")
if sender.isForceTouch {
self.coverView?.isHidden = true
self.selectedImageView?.isHidden = true
self.selectedImageView?.image = nil
} else {
//TODO: handle selecting items of UICollectionView here,
//you can refer to this SO question for more info: https://stackoverflow.com/questions/42372609/collectionview-didnt-call-didselectitematindexpath-when-superview-has-gesture
print("Did select row at indexPath: \(indexPath)")
self.collectionView?.selectItem(at: indexPath, animated: true, scrollPosition: .centeredVertically)
}
default: break
}
}
从这一点开始,您需要自定义视图,使其外观与Facebook一样。
我还在GitHub https://github.com/ChernyshenkoTaras/3DTouchExample上创建了一个小示例项目来演示它