Book Image

Learning Swift Second Edition - Second Edition

By : Andrew J Wagner
Book Image

Learning Swift Second Edition - Second Edition

By: Andrew J Wagner

Overview of this book

Swift is Apple’s new programming language and the future of iOS and OS X app development. It is a high-performance language that feels like a modern scripting language. On the surface, Swift is easy to jump into, but it has complex underpinnings that are critical to becoming proficient at turning an idea into reality. This book is an approachable, step-by-step introduction into programming with Swift for everyone. It begins by giving you an overview of the key features through practical examples and progresses to more advanced topics that help differentiate the proficient developers from the mediocre ones. It covers important concepts such as Variables, Optionals, Closures, Generics, and Memory Management. Mixed in with those concepts, it also helps you learn the art of programming such as maintainability, useful design patterns, and resources to further your knowledge. This all culminates in writing a basic iOS app that will get you well on your way to turning your own app ideas into reality.
Table of Contents (19 chapters)
Learning Swift Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Temporarily saving a photo


To start, we are only going to concern ourselves with temporarily storing our pictures in memory. To do this, we can add an image array as a property of our view controller:

class ViewController: UIViewController {
    
    var photos = [UIImage]()
    
    // ...
}

As we saw in the image picker delegate method, UIKit provides a class UIImage that can represent images. Our photos property can store an array of these instances. This means that the first step for us is to add new images to our property when the callback is called:

    func imagePickerController(
        picker: UIImagePickerController,
        didFinishPickingImage image: UIImage!,
        editingInfo: [NSObject : AnyObject]!
        )
    {
        self.photos.append(image)
        self.dismissViewControllerAnimated(true, completion: nil)
    }

Now every time the user takes or picks a new photo, we add it to our list, which stores all of the images in memory. However, this isn't quite enough, we also...