स्टैक ओवरव्लो पर शोध से मैंने सीखा है कि यह त्रुटि एक प्रकार को बाध्य करने का प्रयास कर रही है जो वैकल्पिक नहीं है, हालांकि इसमें इसका अर्थ नहीं है स्थिति क्योंकि यह इसके बजाय गार्ड का इस्तेमाल किया।सशर्त बाध्यकारी के लिए प्रारंभकर्ता के पास वैकल्पिक प्रकार होना चाहिए, 'UIView' नहीं
func animateTransition(_ transitionContext: UIViewControllerContextTransitioning) {
// Here, we perform the animations necessary for the transition
guard let fromVC = transitionContext.viewController(forKey: UITransitionContextFromViewControllerKey) else { return }
let fromView = fromVC.view
guard let toVC = transitionContext.viewController(forKey: UITransitionContextToViewControllerKey) else { return }
let toView = toVC.view
guard let containerView = transitionContext.containerView() else { return }
if self.presenting {
containerView.addSubview(toView)
}
let animatingVC = self.presenting ? toVC : fromVC
let animatingView = animatingVC.view
let appearedFrame = transitionContext.finalFrame(for: animatingVC)
var alpha: CGFloat = 1
if self.options.contains([.AlphaChange]) {
alpha = 0;
}
let initialAlpha = self.presenting ? alpha : 1
let finalAlpha = self.presenting ? 1: alpha
var dismissedFrame = appearedFrame
let startRect = CGRect(origin: appearedFrame.origin, size: containerView.bounds.size)
let offset = self.calculateStartPointOffset(startRect, options: self.options)
if options.contains([.Dissolve]) && !self.presenting {
dismissedFrame.size = containerView.bounds.size
dismissedFrame.origin = CGPointZero
} else {
dismissedFrame = CGRect(x: offset.x, y: offset.y, width: appearedFrame.width, height: appearedFrame.height)
}
let initialFrame = self.presenting ? dismissedFrame : appearedFrame
let finalFrame = self.presenting ? appearedFrame : dismissedFrame
animatingView?.frame = initialFrame
animatingView?.alpha = initialAlpha
let dumpingValue = CGFloat(self.options.contains([.Interactive]) ? 1 : 0.8)
UIView.animate(withDuration: self.transitionDuration(transitionContext), delay: 0, usingSpringWithDamping: dumpingValue, initialSpringVelocity: 0.2, options: [UIViewAnimationOptions.allowUserInteraction, UIViewAnimationOptions.beginFromCurrentState],
animations:
{() -> Void in
animatingView?.frame = finalFrame
animatingView?.alpha = finalAlpha
})
{ (completed) -> Void in
if !self.presenting {
fromView?.removeFromSuperview()
self.tDelegate?.didDissmisedPresentedViewController()
}
let cancelled = transitionContext.transitionWasCancelled()
transitionContext.completeTransition(!cancelled)
}
}
Xcode इस लाइन पर एक त्रुटि शो:: यहाँ मेरी कोड है
guard let containerView = transitionContext.containerView() else { return }
कौन सी त्रुटि दिखाई गई है? –