Use CocoaPods to manage frameworks, SnapKit for autolaying.

Use CocoaPods, SnapKit, Timer.

Use UITableView, UIRefreshControl, Date, DateFormatter

Use UIPickerView to make the view, UILongPressGestureRecognizer to make a gesture to cheat.

Use UIScrollView to resize picture and display part of it.

Use UIPanGestureRecognizer, CAGradientLayer.

Use UITableViewRowAction, UIAlertController.

Use UIScrollView - scrollViewDidScrol to get offset to resize picture.

Use AVPlayerViewController.

Use UIVisualEffectView, animate().

Use UIApplicationShortcutItem, UIViewControllerPreviewingDelegate.

Use CSSearchableItem to create an item supports Spotlight. Use CSSearchableItemAttributeSet to configurate it. Implement func application(_ application: UIApplication, continue userActivity: NSUserActivity in AppDelegate.swift to process after selecting a result in Spotlight.

Use App Group to share data between App and Extension. Use NSUserDefault to save and load data.

Use CoreData kit. Define entity first. Use appDelegate.persistentContainer.viewContext to save and read data.

Use UIImagePickerControllerDelegate to select photo from library. Use UIImageWriteToSavedPhotosAlbum() to save photo.

Use Core Image, CIFilter to generate QR code.

Use Core Image, CIDetectorto detect face.

Use UIPopoverPresentationControllerDelegate, PopoverMenuViewController.

Use UIViewControllerAnimatedTransitioning, UIViewControllerTransitioningDelegate.

Use UICollectionViewDelegate . Use UIViewControllerAnimatedTransitioning to customize transition.

Use CAShapeLayer to create dircle progress view class.

Use CAAnimationDelegate, CABasicAnimation, CAmediaTimingFunction.

Use CGAffineTransform, UIVIew.animate().

Use UIViewControllerAnimatedTransitioning, CGAffineTransform.

Use UIViewControllerAnimatedTransitioning.

Use AVCapturePhotoCaptureDelegate, AVCaptureDevice, AVCaptureVideoPreviewLayer.

Use Timer.

Override touchesBegin() , touchesMoved to detect touch and save lines between touch points. Override draw() to display all lines.

Use UserDefault.standard to check if it is first launch. Implement UIScrollViewDelegate, use UIPageControl.

Use WatchConnectivity to transfer data between iPhone and Apple Watch.