Swift – blog.ericd.net

May 15, 2017

Getting hour offsets for local time versus a target time zone in Swift

I am currently working on something that will display time in different time zones. However, you need to compare the user’s current time versus those at the target time zones to be accurate. This is what I figured out. It’s easy to get the user’s local time.

let cal = Calendar(identifier: .gregorian)
let date = Date()
let hour = cal.component(.hour, from: date)
let minute = cal.component(.minute, from: date)
let second = cal.component(.second, from: date)
print("\nLOCAL TIME: \(hour):\(minute):\(second)\n")

let cal = Calendar(identifier: .gregorian)

let date = Date()

let hour = cal.component(.hour, from: date)

let minute = cal.component(.minute, from: date)

let second = cal.component(.second, from: date)

print("\nLOCAL TIME: \(hour):\(minute):\(second)\n")

Now, you need to get the time …

May 10, 2017

tvOS UIFocusGuide demystified

A post about tvOS UIFocus enlightenment and a helper Class that I use to help debug my user interface work. Above you’ll notice four buttons (a screenshot from my actual Apple TV). You’ll also notice a total of eight purple boxes with dashed outlines. Each is labeled in all capitals. Those are instances of my …

April 5, 2017

Returning data from an async network operation in Swift

If you’re ever using asynchronous network operations (say GET or POST) and want to return data when calling a method, you’ll quickly understand that it’s not so easy. But you’ll see below how you can do this fairly easily. Let’s say you have a Class that handles all kinds of network communication. I call mine …

March 15, 2017

Getting the rotation angle after CABasicAnimation?

I had a view that I rotate a lot, often more than 360 degrees (spins around a few times). Each time it stops, I wanted to determine the resulting “visual” angle. How does one go about doing that? rotateView is a configured CABasicAnimation:

let rotateView = CABasicAnimation()
let randonAngle = arc4random_uniform(361) + 1440
rotateView.fromValue = 0
rotateView.toValue = Float(randonAngle) * Float(M_PI) / Float(randomBetweenNumbers(firstNum: 90.0, secondNum: 180.0))//180.0
let randomSpeed = randomBetweenNumbers(firstNum: 1.5, secondNum: 2.1)
rotateView.duration = CFTimeInterval(randomSpeed)
rotateView.repeatCount = 0
rotateView.isRemovedOnCompletion = false
rotateView.fillMode = kCAFillModeForwards
rotateView.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
innerRing.layer.add(rotateView, forKey: "transform.rotation.z")

let rotateView = CABasicAnimation()

let randonAngle = arc4random_uniform(361) + 1440

rotateView.fromValue = 0

rotateView.toValue = Float(randonAngle) * Float(M_PI) / Float(randomBetweenNumbers(firstNum: 90.0, secondNum: 180.0))//180.0

let randomSpeed = randomBetweenNumbers(firstNum: 1.5, secondNum: 2.1)

rotateView.duration = CFTimeInterval(randomSpeed)

rotateView.repeatCount = 0

rotateView.isRemovedOnCompletion = false

rotateView.fillMode = kCAFillModeForwards

rotateView.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)

innerRing.layer.add(rotateView, forKey: "transform.rotation.z")

Once done, I dispatch after the randomSpeed duration so I know …

Swift 3: UITableView snap to cells

November 14, 2016

If you have your UITableViews snap to their cells, you’ll end up with a more refined user experience. This solution I have works with cells that are consistent in their height (static). You could always work with dynamic heights if you wanted to.

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
        if scrollView == suggestionsTableView {
            let cellHeight = CGFloat(60.0)
            let y          = targetContentOffset.pointee.y + scrollView.contentInset.top + (cellHeight / 2)
            let cellIndex  = floor(y / cellHeight)
            targetContentOffset.pointee.y = cellIndex * cellHeight - scrollView.contentInset.top
        }
    }

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {

if scrollView == suggestionsTableView {

let cellHeight = CGFloat(60.0)

let y = targetContentOffset.pointee.y + scrollView.contentInset.top + (cellHeight / 2)

let cellIndex = floor(y / cellHeight)

targetContentOffset.pointee.y = cellIndex * cellHeight - scrollView.contentInset.top

As you can see cellHeight is a set float value, it’s …

Swift: Animating a mask for a UIView

October 22, 2015

I recently stumbled upon a really excellent article online entitled “UIDynamics, UIKit or OpenGL? 3 Types of iOS Animations For the Star Wars.” A lot of great discussion about performance of interesting techniques in a iOS user interface. I read through it and without going to the Github repository to check out any code I …

[Swift] Quick number to word conversion

October 16, 2015

If you’re ever setting content for things using loops (who isn’t, right?), you might often use the loop variable in a string to label something. Item 1, Item 2, etc. Especially when you’re simulating or prototyping something that will consume actual live data later on. A nice touch is to get rid of those numerals …

[Swift] UIScrollView snapping into place like in the iOS App Store

October 16, 2015

I was asked recently to modify the UIScrollViews that I implemented in an iOS application design. The request was to have our scroll views behave like the ones that appear in the iOS App Store. Here is a screen capture of that ribbon to familiarize you with the scroll view in question. Alright. In short …

String extension for range of characters/character at nth position

August 17, 2015

I spotted this extension somewhere online a while ago (kjmcneish?) that can come in pretty handy.

extension String {
    
    // Returns a range of characters (e.g. s[0...3])
    subscript (r: Range<Int>) -> String {
        let start = advance(self.startIndex, r.startIndex)
        let end = advance(self.startIndex, r.endIndex)
        return substringWithRange(Range(start: start, end: end))
    }
    
    // Returns the nth character (e.g. s[1])
    subscript (i: Int) -> String {
        
        return self[i...i]
    }
}

extension String {

// Returns a range of characters (e.g. s[0...3])

subscript (r: Range<Int>) -> String {

let start = advance(self.startIndex, r.startIndex)

let end = advance(self.startIndex, r.endIndex)

return substringWithRange(Range(start: start, end: end))

// Returns the nth character (e.g. s[1])

subscript (i: Int) -> String {

return self[i...i]

Usage:

let e = "On my ship, the Rocinante, Wheeling through the galaxies."
let e1 = e[0...1]  // Returns a range of characters ("On")
let e2 = e[3]  //Returns a single character ("m")

let e = "On my ship, the Rocinante, Wheeling through the galaxies."

let e1 = e[0...1] // Returns a range of characters ("On")

let e2 = e[3] //Returns a single character ("m")

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