Swift tips

Some tips about coding in swift efficiently and elegantly. Download two playground files to have fun.

• Funny Swift
• The Dao of Protocol

Funny Swift.playground

This playground file has some tips about how to write funny swift which saves your time and fingers.

Extension of Selector:

private extension Selector {
    static let btnTapped = #selector(ViewController.btnTapped(btn:))
}

btn.addTarget(self, action: .btnTapped, for: .touchUpInside)

Extension of Notification.Name

extension Notification.Name {
    static let changed = NSNotification.Name(rawValue: "changed")
}

NotificationCenter.default.post(name: .changed, object: nil)

To eliminate nil check with flatMap

if let v = city {
    para["city"] = v
}

vs

city.flatMap { para["city"] = $0 }

Managing multiple storyboards

user.storyboard
topic.storyboard
...

let userVC = AppStoryboard.user.viewController(UserViewController.self)

let topicVC = AppStoryboard.topic.viewController("TopicViewController")

Reduce repeat code with Extension

let p = CGPoint(x:10, y:10.1)
let r = CGRect(x:10, y:10, width:100, height:100)

//lazy code
let p = CGPoint(10, 10.1)
let r = CGRect(10, 10, 100, 100)

write code in chain style with Extension

let view = UIView()
    .backgroundColor(.white)
    .tag(1)
    ...

---

The Dao of Protocol.playground

This playground file is all about Protocol and Protocol Oriented Programming.

Isolate builder code

let btn = UIButton() {
    $0.frame = CGRect(x: 10, y: 10, width: 44, height: 44)
    $0.backgroundColor = .red
    ...
}

Keyboard observer

final class ViewController: UIViewController {
    ...

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        addKeyboardObservers()
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        removeKeyboardObservers()
    }
}

Default implementation for Active Record

extension User: RemoteFetchable { }

User.request(RemoteResouce("api.example.com", "/users", .get),
    success: { data in

    },
    failure: { err in

    })

Extension for specific generic

extension Callable where Self.PhoneNumberType : SignedInteger {
    func call() {
        print("this is a number", phone)
    }
}

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