Remove guard statements that could put the app in non-recoverable und…

…efined state
nartex · Jun 30, 2017 · 0fb900d · 0fb900d
1 parent de1deb3
commit 0fb900d
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Showing 3 changed files with 32 additions and 42 deletions.
diff --git a/ImageViewer/AnimatableImageView.swift b/ImageViewer/AnimatableImageView.swift
@@ -11,7 +11,7 @@ final class AnimatableImageView: UIView {
         didSet { update() }
     }
 
-    var image: UIImage = UIImage() {
+    var image: UIImage? {
         didSet {
             imageView.image = image
             update()
@@ -25,19 +25,15 @@ final class AnimatableImageView: UIView {
         imageView.contentMode = .scaleToFill
     }
 
-    convenience init(image: UIImage) {
-        self.init()
-        self.image = image
-        self.imageView.image = image
-    }
-
     required init?(coder aDecoder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
 }
 
 private extension AnimatableImageView {
     func update() {
+        guard let image = image else { return }
+
         switch contentMode {
         case .scaleToFill:
             imageView.bounds = Utilities.rect(forSize: bounds.size)

diff --git a/ImageViewer/Transitions/ImageViewerDismissalTransition.swift b/ImageViewer/Transitions/ImageViewerDismissalTransition.swift
@@ -4,7 +4,7 @@ final class ImageViewerDismissalTransition: NSObject, UIViewControllerAnimatedTr
     fileprivate var transitionContext: UIViewControllerContextTransitioning?
 
     fileprivate let fromImageView: UIImageView
-    fileprivate let toImageView: UIImageView
+    fileprivate var toImageView: UIImageView
 
     fileprivate var animatableImageview = AnimatableImageView()
     fileprivate var fromView: UIView?
@@ -50,28 +50,21 @@ final class ImageViewerDismissalTransition: NSObject, UIViewControllerAnimatedTr
 
     func start(_ transitionContext: UIViewControllerContextTransitioning) {
         self.transitionContext = transitionContext
+        self.fromView = transitionContext.view(forKey: UITransitionContextViewKey.from)!
+        let containerView = transitionContext.containerView
+        let fromSuperView = fromImageView.superview!
+        let image = fromImageView.image ?? toImageView.image
 
-        let container = transitionContext.containerView
-        guard
-            let fromView = transitionContext.view(forKey: UITransitionContextViewKey.from),
-            let image = fromImageView.image ?? toImageView.image else {
-                transitionContext.completeTransition(true)
-                return
-        }
-
-        self.fromView = fromView
-
-        fromView.isHidden = true
-        transitionContext.view(forKey: UITransitionContextViewKey.to)?.isHidden = false
         animatableImageview.image = image
-        animatableImageview.frame = container.bounds
+        animatableImageview.frame = fromSuperView.convert(fromImageView.frame, to: nil)
         animatableImageview.contentMode = .scaleAspectFit
 
-        fadeView.frame = container.bounds
+        fromView?.isHidden = true
+        fadeView.frame = containerView.bounds
         fadeView.backgroundColor = .black
 
-        container.addSubview(fadeView)
-        container.addSubview(animatableImageview)
+        containerView.addSubview(fadeView)
+        containerView.addSubview(animatableImageview)
     }
 
     func cancel() {
@@ -119,7 +112,7 @@ private extension ImageViewerDismissalTransition {
             case .end:
                 self.animatableImageview.contentMode = self.toImageView.contentMode
                 self.animatableImageview.transform = .identity
-                self.animatableImageview.frame = self.toImageView.superview!.convert(self.toImageView.frame, to: UIScreen.main.coordinateSpace)
+                self.animatableImageview.frame = self.toImageView.superview!.convert(self.toImageView.frame, to: nil)
                 self.fadeView.alpha = 0.0
             }
         }

diff --git a/ImageViewer/Transitions/ImageViewerPresentationTransition.swift b/ImageViewer/Transitions/ImageViewerPresentationTransition.swift
@@ -13,33 +13,34 @@ final class ImageViewerPresentationTransition: NSObject, UIViewControllerAnimate
     }
 
     func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
-        let container = transitionContext.containerView
-        guard let toView = transitionContext.view(forKey: UITransitionContextViewKey.to),
-            let parentView = fromImageView.superview,
-            let image = fromImageView.image else {
-            transitionContext.completeTransition(true)
-            return
-        }
-
-        let imageView = AnimatableImageView(image: image)
-        imageView.frame = parentView.convert(fromImageView.frame, to: UIScreen.main.coordinateSpace)
+        let containerView = transitionContext.containerView
+        let toView = transitionContext.view(forKey: UITransitionContextViewKey.to)!
+        let fromParentView = fromImageView.superview!
+
+        let imageView = AnimatableImageView()
+        imageView.image = fromImageView.image
+        imageView.frame = fromParentView.convert(fromImageView.frame, to: nil)
         imageView.contentMode = fromImageView.contentMode
 
-        let fadeView = UIView(frame: container.bounds)
+        let fadeView = UIView(frame: containerView.bounds)
         fadeView.backgroundColor = .black
         fadeView.alpha = 0.0
 
-        toView.frame = container.bounds
+        toView.frame = containerView.bounds
         toView.isHidden = true
         fromImageView.isHidden = true
 
-        container.addSubview(toView)
-        container.addSubview(fadeView)
-        container.addSubview(imageView)
+        containerView.addSubview(toView)
+        containerView.addSubview(fadeView)
+        containerView.addSubview(imageView)
 
-        UIView.animate(withDuration: transitionDuration(using: transitionContext), delay: 0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0, options: .curveEaseOut,  animations: {
+        UIView.animate(withDuration: transitionDuration(using: transitionContext),
+                       delay: 0,
+                       usingSpringWithDamping: 0.8,
+                       initialSpringVelocity: 0,
+                       options: .curveEaseOut,  animations: {
             imageView.contentMode = .scaleAspectFit
-            imageView.frame = container.bounds
+            imageView.frame = containerView.bounds
             fadeView.alpha = 1.0
         }, completion: { _ in
             toView.isHidden = false