是否有可能从UIViewController检测触摸并获取触摸的位置,UIViewController当前用作3D Touch的previewingContext视图控制器？ (当触摸从左向右移动时,我想更改预览控制器内的图像)
我尝试了两个touchesBegan和touchesMoved都没有被解雇.
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
解决方法
如果您想获得与FaceBook的3D Touch功能相同的结果,您需要创建自己的3D Touch手势类
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viewDidLoad方法的ViewController中添加此手势
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.在中心添加UICollectionView和UIImageView上方的封面视图,并在代码中将其与IBOutlets连接.
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