Changing A UIView Variable From ViewController In Swift

Question

I've been stumbling along with Swift lately, and have come across a concept that I think I understood, but can't seem to get it working properly.

In my app, I have a ViewController with a View that I've added in IB. I've set the Custom Class of my View to be "RingView", which lives in my RingView.swift file (for context, RingView draws a ring).

This is technically working fine, as my ring is rendered appropriately when I run the app. What I'm trying to do is to set the width of the ring's line and the stroke color programmatically from my ViewController.swift file. While I'm not getting any errors when I build, despite me setting the lineWidth to 10, for example, the width of the line is always 1 when I build.

RingView.swift

class RingView: UIView {

var lineWidth: CGFloat = 1

var strokeColor = UIColor(red: 147.0/255.0, green: 184.0/255.0, blue: 255.0/255.0, alpha: 1.0).CGColor

let circlePathLayer = CAShapeLayer()
let circleRadius: CGFloat = 105.0

override init(frame: CGRect) {
    super.init(frame: frame)
    configure()
}

required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    configure()
}

func configure() {

    circlePathLayer.frame = bounds
    circlePathLayer.lineWidth = lineWidth
    circlePathLayer.fillColor = UIColor.clearColor().CGColor
    circlePathLayer.strokeColor = strokeColor

    layer.addSublayer(circlePathLayer)
    backgroundColor = UIColor.clearColor()
}

func circleFrame() -> CGRect {
    var circleFrame = CGRect(x: 0, y: 0, width: 2*circleRadius, height: 2*circleRadius)
    circleFrame.origin.x = CGRectGetMidX(circlePathLayer.bounds) - CGRectGetMidX(circleFrame)
    circleFrame.origin.y = CGRectGetMidY(circlePathLayer.bounds) - CGRectGetMidY(circleFrame)
    return circleFrame
}

func circlePath() -> UIBezierPath {
    return UIBezierPath(ovalInRect: circleFrame())
}

override func layoutSubviews() {
    super.layoutSubviews()
    circlePathLayer.frame = bounds
    circlePathLayer.path = circlePath().CGPath
}

}

ViewController.swift

import UIKit

class ViewController: UIViewController {

@IBOutlet var titleLabel: UILabel!

@IBOutlet weak var RingViewInner: RingView!


var detailItem: Minion? {
    didSet {
        // Update the view.
        self.configureView()
    }
}

func configureView() {

    // Update the user interface for the detail item.
    if let detail = self.detailItem {

        //Set the label for the title name
        if let label = titleLabel {
            label.text = detail.title!
        }
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    RingViewInner?.strokeColor = UIColor(red: 255.0/255.0, green: 0.0/255.0, blue: 0.0/255.0, alpha: 0.0).CGColor
    RingViewInner?.lineWidth = 10
    RingViewInner.setNeedsDisplay()

    //Show the configured context of data
    self.configureView()
}
}

Any thoughts would be immensely appreciated. Thank you!

You may want to override drawRect() in your custom view class to do the drawing of your view. Don't know if that'll solve you issue or not, but it may help. — trevorj
– trevorj, Commented Jul 3, 2015 at 22:38

Akhilendra Singh · Accepted Answer · 2017-04-19 10:12:45Z

I am going to explain this with the help of the following example where I have a simple view with an UIImageView inside of it and later on I want to set its image from ViewController. Following code is for the view-

class ImagePreviewView: UIView {
    var imgView: UIImageView!
    var img: UIImage!

    override init(frame: CGRect) {
        super.init(frame: frame)

        imgView=UIImageView(frame: CGRect(x: 0, y: 0, width: self.frame.width, height: self.frame.height))
        imgView.contentMode = .scaleAspectFit

        self.addSubview(imgView)
    }

    func setImage(img: UIImage){
        self.imgView.image=img
    }

    override func didMoveToSuperview() {
        self.backgroundColor=UIColor.black
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

Now the code for the ViewController

class ViewController: UIViewController {
    override func viewDidLoad() {
        imagePreviewView = ImagePreviewView(frame: CGRect(x: self.view.frame.width, y: 0, width: self.view.frame.width-sideStripWidth, height: self.view.frame.height-140))
        self.view.addSubview(imagePreviewView)
    }

    //call this function to set image of imagePreviewView
    func changeImage(img){
        imagePreviewView.setImage(img: img)
    }
}

The changeImage function calls the setImage function in imagePreviewView to change the image. Hope it helps.

Chen Lu · Accepted Answer · 2016-04-06 14:59:13Z

0

you can make the variable global, for example you can put it out side the class "ViewController"

answered Apr 6, 2016 at 14:59

Chen Lu

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