Improve swift safety

Gallery/PostCollectionView.swift

@@ -69,6 +69,8 @@ class PostCollectionView: UICollectionView, UICollectionViewDataSource, UICollec
         
         let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "postCell", for: indexPath as IndexPath) as! PostViewCell
         
+        cell.name = post.value(forKey: "name") as? String
+        
         let imagePath = documentsPath.appendingPathComponent(post.value(forKey: "name") as! String).path
         
         if(FileManager.default.fileExists(atPath: imagePath)) {
@@ -279,8 +281,10 @@ class PostCollectionView: UICollectionView, UICollectionViewDataSource, UICollec
         let model = posts[indexPath.item]
         let itemProvider = NSItemProvider(object: (cellForItem(at: indexPath) as! PostViewCell).imageView.image!)
         itemProvider.suggestedName = model.value(forKey: "name") as? String
-         let dragItem = UIDragItem(itemProvider: itemProvider)
+        
-         dragItem.localObject = model //We can set the localObject property for convenience
+        let dragItem = UIDragItem(itemProvider: itemProvider)
-         return [dragItem]
+        dragItem.localObject = model //We can set the localObject property for convenience
+        
+        return [dragItem]
     }
 }

Gallery/PostViewCell.swift

@@ -1,7 +1,8 @@
 import UIKit
 
 class PostViewCell: UICollectionViewCell {
-
+    var name: String?
+    
     @IBOutlet weak var imageView: UIImageView!
 }
 

Gallery/PostViewController.swift

@@ -4,32 +4,34 @@ import AVFoundation
 import AVKit
 
 class PostViewController: UIViewController {
-    @IBOutlet weak var imageView: UIImageView!
+    @IBOutlet weak var imageView: UIImageView?
-    
+    @IBOutlet weak var shareButton: UIBarButtonItem?
+
     var post: NSManagedObject?
     var image: UIImage?
     var isPopup: Bool = false
-    @IBOutlet weak var shareButton: UIBarButtonItem!
     
     let documentsPath : URL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0].absoluteURL
     
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
         
-        if(image == nil) {
+        if post != nil {
-            let imagePath = documentsPath.appendingPathComponent(post!.value(forKey: "name") as! String).path
+            if image == nil {
-            
+                let imagePath = documentsPath.appendingPathComponent(post!.value(forKey: "name") as! String).path
-            if((post?.value(forKey: "type") as? String) == "public.mpeg-4") {
+                
-                self.image = generateThumbnail(path: URL(fileURLWithPath: imagePath))
+                if((post?.value(forKey: "type") as? String) == "public.mpeg-4") {
-            } else {
+                    self.image = generateThumbnail(path: URL(fileURLWithPath: imagePath))
-                self.image = UIImage(contentsOfFile: imagePath)
+                } else {
+                    self.image = UIImage(contentsOfFile: imagePath)
+                }
             }
-        }
             
-        imageView.image = self.image
+            imageView?.image = self.image
-        
+            
-        if(isPopup) {
+            if(isPopup) {
-            navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(closePopup))
+                navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(closePopup))
+            }
         }
     }
     
@@ -50,11 +52,15 @@ class PostViewController: UIViewController {
     
     override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
         if segue.identifier == "showTags" {
-            let newViewController = segue.destination as! EditTagsViewController
+            guard let newViewController = segue.destination as? EditTagsViewController else {
+                return
+            }
             
             newViewController.post = self.post as? Post
         } else if segue.identifier == "showInfo" {
-            let newViewController = segue.destination as! InfoViewController
+            guard let newViewController = segue.destination as? InfoViewController else {
+                return
+            }
             
             newViewController.post = self.post as? Post
             newViewController.image = self.image
@@ -87,6 +93,7 @@ extension PostViewController {
 
 
 #if targetEnvironment(macCatalyst)
+
 private let EditButtonToolbarIdentifier = NSToolbarItem.Identifier(rawValue: "OurButton")
 private let ShareButtonToolbarIdentifier = NSToolbarItem.Identifier(rawValue: "OurButton2")
 private let InfoButtonToolbarIdentifier = NSToolbarItem.Identifier(rawValue: "OurButton3")
@@ -144,4 +151,5 @@ extension PostViewController: NSToolbarDelegate {
         return nil
     }
 }
+
 #endif

Gallery/SceneDelegate.swift

@@ -12,34 +12,21 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
         }
         
         #if targetEnvironment(macCatalyst)
-        guard let windowScene = (scene as? UIWindowScene) else { return }
+            guard let windowScene = (scene as? UIWindowScene) else {
-        let toolbar = NSToolbar(identifier: "MyToolbar")
+                return
-        toolbar.delegate = (window?.rootViewController as! UINavigationController).topViewController as? NSToolbarDelegate
+            }
-        windowScene.titlebar!.toolbar = toolbar
-        windowScene.titlebar!.titleVisibility = .hidden
-        toolbar.allowsUserCustomization = true
-        
-        (window?.rootViewController as! UINavigationController).navigationBar.isHidden = true
         
+            let toolbar = NSToolbar(identifier: "Toolbar")
+            toolbar.delegate = (window?.rootViewController as! UINavigationController).topViewController as? NSToolbarDelegate
+            toolbar.allowsUserCustomization = true
+
+            windowScene.titlebar!.toolbar = toolbar
+            windowScene.titlebar!.titleVisibility = .hidden
+            
+            (window?.rootViewController as! UINavigationController).navigationBar.isHidden = true
         #endif
     }
     
-    func sceneDidDisconnect(_ scene: UIScene) {
-        
-    }
-    
-    func sceneDidBecomeActive(_ scene: UIScene) {
-        
-    }
-    
-    func sceneWillResignActive(_ scene: UIScene) {
-        
-    }
-    
-    func sceneWillEnterForeground(_ scene: UIScene) {
-        
-    }
-    
     func sceneDidEnterBackground(_ scene: UIScene) {
         (UIApplication.shared.delegate as? AppDelegate)?.saveContext()
     }
@@ -48,14 +35,12 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
         if activity.activityType == "post" {
             if let photoID = activity.userInfo?["name"] as? String {
                 if let photoDetailViewController = PostViewController.loadFromStoryboard() {
-                    
                     guard let appDelegate =
                         UIApplication.shared.delegate as? AppDelegate else {
                             return false
                     }
                     
-                    let managedContext =
+                    let managedContext = appDelegate.persistentContainer.viewContext
-                        appDelegate.persistentContainer.viewContext
                     
                     let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Post")
                     
@@ -65,7 +50,11 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
                     do {
                         let result = try managedContext.fetch(request)
                         
-                        photoDetailViewController.post = result[0] as? NSManagedObject
+                        guard let object = result[0] as? NSManagedObject else {
+                            return false
+                        }
+                        
+                        photoDetailViewController.post = object
                         photoDetailViewController.isPopup = true
                         
                         if let navigationController = window?.rootViewController as? UINavigationController {

Gallery/ViewController.swift

@@ -83,19 +83,23 @@ class ViewController: UIViewController, UIDocumentPickerDelegate {
     override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
         if identifier == "showPost" {
             #if targetEnvironment(macCatalyst)
-            let index = self.collectionView.indexPathsForSelectedItems?.first
+                guard let cell = sender as? PostViewCell else {
-            
+                    return false
-            let post = self.collectionView.posts[index!.row]
+                }
-            
+         
-            let activity = NSUserActivity(activityType: "post")
+                guard let name = cell.name else {
-            activity.userInfo = ["name": post.value(forKey: "name") as! String]
+                    return false
-            activity.isEligibleForHandoff = true
+                }
-            
+                
-            UIApplication.shared.requestSceneSessionActivation(nil, userActivity: activity, options: nil, errorHandler: nil)
+                let activity = NSUserActivity(activityType: "post")
-            
+                activity.userInfo = ["name": name]
-            return false
+                activity.isEligibleForHandoff = true
+                
+                UIApplication.shared.requestSceneSessionActivation(nil, userActivity: activity, options: nil, errorHandler: nil)
+                
+                return false
             #else
-            return true
+                return true
             #endif
         }
         
@@ -124,7 +128,7 @@ extension ViewController: NSToolbarDelegate {
     func toolbarAllowedItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] {
         return toolbarDefaultItemIdentifiers(toolbar)
     }
-    
+        
     func toolbar(_ toolbar: NSToolbar, itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier, willBeInsertedIntoToolbar flag: Bool) -> NSToolbarItem? {
         if (itemIdentifier == OurButtonToolbarIdentifier2) {
             let barButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.add,