An example of using a block (closure) as a class property in Swift.

class ChatViewController: UIViewController {

    private var someClosure: (() -> Void)?
    private var anotherClosure: ((arg: Double) -> Bool)?

    func executeClosures() {
        if self.someClosure != nil {
            self.someClosure()
        }

        if self.anotherClosure != nil {
            let boolResult = self.anotherClosure(arg: 2.0)
        }
    }

    func addSelfClosure(closure: (() -> Void)!) {
        self.someClosure = closure
    }

    func printSomething() {
        self.addSelfClosure() {
            print("closure called")
        }
        self.executeClosures() // prints: closure called
    }

} 

CompareShots version 1.2 has been released.

I released it because one of the users emailed me asking to hide the logo and text after an image is selected, because otherwise, if the image is not full-screen, they stick out from behind it or show through. While I was at it, I decided to level up the app a bit more. At last, my subscription to various new libraries came in handy. Now you can draw on top of images. With different colors and brushes of different sizes. One evening, and this beauty was ready :)

I finally got around to writing about Assassin's Creed Unity, which I actually finished a few months ago; family matters left me no time to write a post while the impressions were still fresh.

The game starts with a rather vague prologue about the Templars and their Grand Master Jacques de Molay. As everyone knows, he was burned at the stake, but the prologue itself is not particularly connected to the game's plot. Somewhere they mention some grand plan of the Grand Master that the French Templars are supposedly going to carry out centuries later, but overall it makes for a pretty unclear opening.

The game itself follows a young man named Arno. His father was murdered when he was little, and the head of the Templar order took him in. One fine evening that man is murdered, and Arno, who happens to be at the scene, is accused of it and thrown into the Bastille. Then the revolution begins, and his assassin cellmate invites Arno into their Brotherhood. Along the way Arno tries to find out who was behind the murder. On top of that, he is in love with the daughter of his murdered adoptive father, who, ironically, is also a Templar.

The locations and scenery in the game are, of course, beautiful. Paris is gloomy, but beautiful, with many landmarks.

You can climb every landmark. Quite often, you can even get inside. It's always interesting to explore familiar places you've seen in real life.

They changed the gameplay quite a lot in this installment. Unfortunately, they completely removed the assassin brothers I liked so much: you can no longer mark a target and sic an assassin on it. There are many places to run and jump, you can enter a lot of buildings and pass through them, go up floors, and pick locks. Parkour and running feel a bit clunky in places and slow in others, but overall there is nothing fundamentally new; compared to the Ezio games, it feels more simplified, where you could jump or pull yourself up with the hookblade.

The city has several districts, each with its own difficulty, scenery, and inhabitants. In some places there are riots in honor of the revolution, while others are still calm.

During the story there are certain glitches in time (after all, we are still reliving an ancestor's memories through the Animus), where we hide so the system cannot track us. As a result, you get to run around Paris in other time periods. Climb the Eiffel Tower or see the Statue of Liberty before it is sent to the USA.

The combat system changed a lot. Now it is not so easy to stand against a crowd of enemies. In the early games you could just hold block and nobody would touch you; you only had to counterattack in time. Here everything is harder: it is easier to defeat the hero, every enemy has a power level (difficulty), and fighting even a couple of strong opponents is already pretty hard.

There are many different locations. Besides districts, there are lots of interiors. Palaces, for example. Lots of catacombs and dungeons.

I really liked the new investigation mini-missions. You arrive at a crime scene, collect clues, question witnesses, and expose the murderer. Great stuff.

There are a ridiculous number of missions in the game, by the way. All sorts of completion-meter stuff like collecting every chest, and there are several types of them. Rebuild your headquarters, buy and open taverns, increase their profits; all of this is also split into districts, so you can tackle it district by district. In general, you can spend more time on that than on the story itself. Many of them are rather repetitive and even routine. I liked the ability to buy weapons, clothes, and armor, of which the game has plenty. Changing the character's look and leveling him up through weapons and armor is always interesting.

The key story missions are certainly interesting. What sells them is that they can be completed in several ways: go in head-on, use some trickery, enter one way or another. You can also fulfill extra conditions so that, for example, people will help you by rushing the guards, delaying them and giving you a chance to escape.

Overall, I liked the game more than I disliked it. But somehow it does not reach the level of part II, Brotherhood, and Revelations in terms of story. They stuffed it with a lot of grindy completionist fluff. The plot is vague and the storytelling is not built especially well. Of course, the graphics are beautiful, the gameplay changed a lot, and in some places it became better while in others it became questionable. We'll see what happens in the next entries.

It was 2016, and to change the colors of a badge inside a tab you still had to create your own UI element and add it to the tab bar manually. A working solution in Swift:

// MARK: - UITabBarController extension for badges
extension UITabBarController {

    /**
    Set badges

    - parameter badgeValues: values array
    */
    func setBadges(badgeValues: [Int]) {

        for view in self.tabBar.subviews {
            if view is CustomTabBadge {
                view.removeFromSuperview()
            }
        }

        for index in 0...badgeValues.count-1 {
            if badgeValues[index] != 0 {
                addBadge(
                    index: index,
                    value: badgeValues[index],
                    color:UIColor.yellowColor(),
                    font: UIFont.systemFontOfSize(11)
                )
            }
        }

    }

    /**
    Add badge for tab

    - parameter index: index of tab
    - parameter value: badge value
    - parameter color: badge color
    - parameter font: badge font
    */
    func addBadge(index: Int, value: Int, color: UIColor, font: UIFont) {
        let badgeView = CustomTabBadge()

        badgeView.clipsToBounds = true
        badgeView.textColor = UIColor.whiteColor()
        badgeView.textAlignment = .Center
        badgeView.font = font
        badgeView.text = String(value)
        badgeView.backgroundColor = color
        badgeView.tag = index
        tabBar.addSubview(badgeView)

        self.positionBadges()
    }

    override public func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        self.tabBar.setNeedsLayout()
        self.tabBar.layoutIfNeeded()
        self.positionBadges()
    }

    /**
    Positioning
    */
    func positionBadges() {

        var tabbarButtons = self.tabBar.subviews.filter { (view: UIView) -> Bool in
            return view.userInteractionEnabled // only UITabBarButton are userInteractionEnabled
        }

        tabbarButtons = tabbarButtons.sort({ $0.frame.origin.x < $1.frame.origin.x })

        for view in self.tabBar.subviews {
            if view is CustomTabBadge {
                let badgeView = view as! CustomTabBadge
                self.positionBadge(badgeView, items:tabbarButtons, index: badgeView.tag)
            }
        }
    }

    /**
    Position for badge

    - parameter badgeView: badge view
    - parameter items: tab bar buttons array
    - parameter index: index of tab
    */
    func positionBadge(badgeView: UIView, items: [UIView], index: Int) {

        let itemView = items[index]
        let center = itemView.center

        let xOffset: CGFloat = 12
        let yOffset: CGFloat = -14
        badgeView.frame.size = CGSizeMake(17, 17)
        badgeView.center = CGPointMake(center.x + xOffset, center.y + yOffset)
        badgeView.layer.cornerRadius = badgeView.bounds.width/2
        tabBar.bringSubviewToFront(badgeView)
    }

}

/// Custom UILabel class for badge view
class CustomTabBadge: UILabel {}

A very nice bit of syntactic sugar: a function for running code with a delay via Grand Central Dispatch using dispatch_after:

Update 2024. Swift 5.5+

func someMethod() async throws {
    // sleep for 2 seconds
    try await Task.sleep(nanoseconds: NSEC_PER_SEC * 2)
}

Swift 2:

/**
Delay function using GCD. Syntax sugar.

- parameter delay: delay in seconds
- parameter closure: closure code to execute after delay
*/
func delay(delay:Double, closure:()->()) {
    dispatch_after(
        dispatch_time(
            DISPATCH_TIME_NOW,
            Int64(delay * Double(NSEC_PER_SEC))
        ),
    dispatch_get_main_queue(), closure)
}

Swift 3:

/**
Delay function using GCD. Syntax sugar.

- parameter delay: delay in seconds
- parameter closure: closure code to execute after delay
*/
func delay(_ delay: Double, closure:()->()) {
    let when = DispatchTime.now() + delay
    DispatchQueue.main.asyncAfter(deadline: when, execute: closure)
}

Usage:

delay(0.4) {
    // code
}

Cheat sheet: how to present a UIViewController over another one so that it is semi-transparent and the content underneath shows through.

In Storyboard, set the Segue Kind field to «Present Modally». For the UIViewController you are showing, set the background color to Clear Color, then create an inner background (an image or another UIView) with an alpha value, for example 0.5.

In code:

self.performSegueWithIdentifier("segueName", sender: self)

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "segueName" {
        let vc = segue.destinationViewController as! YourViewController
        vc.modalPresentationStyle = .Custom
    }
}

I decided to study what websites look like in Google's Material Design. I found their Material Design Lite library and dropped it into the site. It seems more readable now, it has responsive design out of the box so it can be read on phones, and it looks better on Retina now too. It is convenient when you can assemble what you like from ready-made pieces. I like the result more than what you can build, for example, with Twitter Bootstrap.

I thought about the header for a long time and in the end lovingly stole the idea from Apple's page dedicated to WWDC '16 :) I implemented it in SVG and animated the cursor in JS (though only in the desktop version). I looked at Polymer, but it did not really start up for me right away, and I had already done a lot with MDL by then. The idea of web components is certainly cool, and it looks great semantically, but for now I will postpone it until browser support gets better. There is also a feeling that everything there is heavily tied to Node.JS, and I no longer want to rewrite it in Node — I am waiting for new Swift releases so I can rewrite it in Swift.