Force custom view to redraw (or invalidate) using a timer - ios

Question

I've created a custom widget, which is animated. Now my problem is that I can't redraw the view, when the corresponding data gets updated.
Just don't hold anything against me in the code. This is my first piece of code in swift and I haven't worked with neither swift nor with Objective-C :-D
And also I've read the following questions, but they didn't help me:
How to force a view to render itself?
what-is-the-most-robust-way-to-force-a-uiview-to-redraw
p.s. : I can see the output of print(digit.phase) in the console.
p.s.s: I've also used performSelectorOnMainThread for calling the setNeedsDisplay function
The code:
import UIKit
struct Digit {
var targetDigit: Int
var currentDigit: Int
var phase: Float
}
#IBDesignable class RollerCounter: UIView {
var view: UIView!
var viewRect: CGRect!
var intNumber: Int
var digits = [Digit]()
let baseY = 20
var timer: NSTimer?
#IBInspectable var number: Int {
get {
return intNumber
}
set(number) {
intNumber = number
digits = []
var tempNumber:Int = intNumber
while tempNumber > 0 {
digits.append(Digit(targetDigit: tempNumber % 10, currentDigit: Int(rand()) % 10, phase: 0.0))
tempNumber /= 10
}
}
}
//init
override init(frame: CGRect) {
// set properties:
intNumber = 1111
super.init(frame: frame)
// setup the thing!
setup()
}
required init?(coder aDecoder: NSCoder) {
intNumber = 1111
super.init(coder: aDecoder)
// setup the thing
setup()
}
// Inital setup
func setup() {
let viewRect = CGRect(x: 0, y: 0, width: 280, height: 40)
view = UIView(frame: viewRect)
view.frame = bounds
view.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
addSubview(view)
self.setNeedsDisplay()
backgroundColor = UIColor(red: 1, green: 1, blue: 1, alpha: 0.0)
}
func animate() {
timer = NSTimer.scheduledTimerWithTimeInterval(0.016, target: self, selector: Selector("tick"), userInfo: nil, repeats: true)
}
func tick() {
for var digit in digits {
digit.phase += Float(rand() % 100) / 100
print(digit.phase)
}
setNeedsDisplay()
//TEST: Also tested this
// if let rect = viewRect {
// drawRect(rect)
// } else {
// viewRect = CGRect(x: 0, y: 0, width: 280, height: 40)
// drawRect(viewRect
// }
}
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func drawRect(rect: CGRect) {
// Drawing code
var tempNumber: Int = number
let strTempNumber = String(tempNumber)
var index: Int = 1
let width = Float(rect.width)
let charWidth: Float = Float(rect.width) / Float(strTempNumber.characters.count)
let charHeight: CGFloat = 36
let color = UIColor.blackColor()
let font: UIFont = UIFont(name: "Helvetica Neue", size: charHeight)!
let paraStyle = NSMutableParagraphStyle()
paraStyle.lineSpacing = 6.0
let skew = 0.1
let textAttribs = [
NSForegroundColorAttributeName: color,
NSParagraphStyleAttributeName: paraStyle,
NSObliquenessAttributeName: skew,
NSFontAttributeName: font
]
for digit in digits {
let strCurrentDigit: NSString = String(digit.currentDigit) as NSString
let strNextDigit: NSString = String(digit.currentDigit - 1) as NSString
let xPos = width - Float(index) * charWidth
let yPos = Float(baseY) + Float(charHeight) * digit.phase
let point: CGPoint = CGPoint(x: Int(xPos), y: Int(yPos))
strCurrentDigit.drawAtPoint(point, withAttributes: textAttribs)
let nextDigitYPos = yPos - Float(charHeight) * 1.2
let nextDigitPoint: CGPoint = CGPoint(x: Int(xPos), y: Int(nextDigitYPos))
strNextDigit.drawAtPoint(nextDigitPoint, withAttributes: textAttribs)
index++
tempNumber /= 10
}
}
}

Answer 1

Sorry folks. My bad :-(
There's nothing wrong with the invalidation system. Here's what's wrong:
for var digit in digits {
digit.phase += Float(rand() % 100) / 100
print(digit.phase)
}
As it turns out, the changes to phase only get reflected in the local digit instance inside the for loop
But just to be clear, the setNeedsDisplay() call inside the tick method is crucial for the view to be updated.