Access variable in ViewController from a different class in Swift - ios

Question

I have a slider sliderLineSize and a variable lineSize in a ViewController. The UISlider sliderLineSize changes lineSize. However, lineSize actually used in the drawRect section of the viewLine class which attaches to a UIView.
Question:
How do I pass or make accessible the variable lineSize which is set in the ViewController to the class viewLine where it is used in drawRect?
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var myView: UIView!
#IBOutlet weak var myImageView: UIImageView!
var lineSize: Int = 1
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
myImageView.alpha = 0.5
}
#IBAction func sliderLineSize(sender: UISlider) {
lineSize = Int(sender.value)
}
}
class viewLine: UIView {
let path=UIBezierPath()
var incrementalImage:UIImage?
var previousPoint:CGPoint = CGPoint.zero
var strokeColor:UIColor?
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func drawRect(rect: CGRect) {
incrementalImage?.drawInRect(rect)
path.lineWidth = lineSize
path.stroke()
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touch: AnyObject? = touches.first
let currentPoint = touch!.locationInView(self)
path.moveToPoint(currentPoint)
previousPoint=currentPoint
self.setNeedsDisplay()
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
let touch: AnyObject? = touches.first
let currentPoint = touch!.locationInView(self)
let midPoint = self.midPoint(previousPoint, p1: currentPoint)
path.addQuadCurveToPoint(midPoint,controlPoint: previousPoint)
previousPoint=currentPoint
path.moveToPoint(midPoint)
self.setNeedsDisplay()
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.drawBitmap()
self.setNeedsDisplay()
path.removeAllPoints()
}
func midPoint(p0:CGPoint,p1:CGPoint)->CGPoint {
let x=(p0.x+p1.x)/2
let y=(p0.y+p1.y)/2
return CGPoint(x: x, y: y)
}
func drawBitmap() {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, true, 1)
strokeColor?.setStroke()
if((incrementalImage) == nil){
let rectPath:UIBezierPath = UIBezierPath(rect: self.bounds)
UIColor.whiteColor().setFill()
rectPath.fill()
}
incrementalImage?.drawAtPoint(CGPointZero)
path.stroke()
incrementalImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
}

Answer 1

There are two main ways to do this.
Option 1:
Give your ViewLine class its own lineSize property:
class ViewLine: UIView {
var lineSize = 1
}
Give ViewController a reference to ViewLine, and use a property observer to update the property inside viewLine whenever it changes in ViewController:
class ViewController: UIViewController {
// v~~~ be sure to connect this outlet in interface builder
#IBOutlet weak var viewLine: ViewLine!
var lineSize = 1 {
didSet {
viewLine.lineSize = lineSize
}
}
}
Now your ViewLine class will have its own lineSize property that can be accessed from within its drawRect method directly.
Option 2:
Give your ViewLine class a reference to ViewController:
class ViewLine: UIView {
// v~~~ be sure to connect this outlet in interface builder
#IBOutlet weak var controller: ViewController!
}
Now, in your drawRect method, replace path.lineWidth = lineSize with path.lineWidth = controller.lineSize.
Basically, one of your classes needs a reference to the other in order for them to be able to communicate.

Answer 2

You should make Singleton Model class. A singleton class can be accessed from anywhere. Here is how you should create a singleton class in swift.
class ApplicationModel {
class var sharedInstance: ApplicationModel {
get {
struct Static {
static var instance: ApplicationModel? = nil
static var token: dispatch_once_t = 0
}
dispatch_once(&Static.token, {
Static.instance = ApplicationModel()
})
return Static.instance!
}
}
var lineSize = 1
}
Inside ViewController
override func viewDidLoad() {
super.viewDidLoad()
//Instantiate ApplicationModel
//GET
let lineSize = ApplicationModel.sharedInstance.lineSize
//SET
ApplicationModel.sharedInstance.lineSize = 5
}
Inside viewLine
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
//Access Application Model
//GET
let lineSize = ApplicationModel.sharedInstance.lineSize
//SET
ApplicationModel.sharedInstance.lineSize = 5
}
Hope this helps!