Swift Practice

This is a Git repository that I use to store some playgrounds where I practice Swift functionality.

Auto Layout Practice

Some exmaples ranging from basic view placement all the way to remaking constraints and updating them based on user interaction within the view. Click on the pictures to see their source code or here to see a more detailed Readme.

Table View Practice

Some examples ranging from a basic Table View all the way to a Table View implementing a custom cell with Auto Layout and Async image loading. Click on the pictures to see their source code or here to see a more detailed Readme.

Collection View Practice

Some examples ranging from a basic Collection View all the way to a Collection View implementing a custom cell with Auto Layout and Async image loading and pagination. Click on the pictures to see their source code or here to see a more detailed Readme.

Networking Practice

Practicing networking by starting with basic networking calls and slowly introducing more complex additions such as Result types and Generics

Basic Networking

Expand for code block:

func fetchItunesData(completion: @escaping (FeedResponse?, Error?) -> ()) {
    guard let url = URL(string: urlString) else { return }
    
    URLSession.shared.dataTask(with: url) { (data, resp, error) in
        if let err = error {
            completion(nil, err)
            return
        }
        do {
            let albumData = try JSONDecoder().decode(FeedResponse.self, from: data!)
            completion(albumData, nil)
        } catch let jsonError {
            completion(nil, jsonError)
        }
    }.resume()
}

Networking with Results

Expand for code block:

func fetchItunesDataWithResults(completion: @escaping (Result<FeedResponse, Error>) -> ()) {
	URLSession.shared.dataTask(with: url) { (data, resp, err) in
        if let err = err {
            completion(.failure(err))
            return
        }
    ...

fetchItunesDataWithResults { (result) in
    switch result {
    case .success(let data):
        guard let resultData = data.feed.results else { return }
        
        resultData.forEach({ (album) in
            if let name = album.name {
                print(name)
            }
        })
    ...
}

Networking with Generics and Results

Expand for code block:

public func fetchGenericData<T: Decodable>(urlString: String, completion: @escaping ((Result<T, Error>) -> () )) {
	...
    do {
       	let dataResponse = try JSONDecoder().decode(T.self, from: data)
        completion(.success(dataResponse))
    } catch let jsonError {
        completion(.failure(jsonError))
    }
}

fetchGenericData(urlString: urlString) { (result: Result<FeedResponse, Error>) in
    ...

Utilities

Some extensions and helpers I've found to be extremely helpful while developing. All credit given, where necessary, in the playground file.

Adding Images with a Cache (Table Views)

Expand for code block:

let imageCache = NSCache<AnyObject, AnyObject>()

class CustomImageView: UIImageView {
    var imageUrlString: String?
    func loadImageUsingUrlString(_ urlString: String) {
        let url = URL(string: urlString)
        imageUrlString = urlString
        image = nil

        if let imageFromCache = imageCache.object(forKey: urlString as AnyObject) as? UIImage {
            self.image = imageFromCache
            return
        }
        URLSession.shared.dataTask(with: url!) { (data, response, error) in
            if error != nil {
                print(error!)
                return
            }
            DispatchQueue.main.async {
                let imageToCache = UIImage(data: data!)
                if self.imageUrlString == urlString {
                    self.image = imageToCache
                }
                imageCache.setObject(imageToCache!, forKey: urlString as AnyObject)
            }
        }.resume()
    }
}