How to change color of Triangle figure using drawRect on Swift - swift

Question

I have made triangle view, called UpTriangleView. It is used in order to show vote. When they are tapped, I want to change their color. I wanna UIColor.grayColor().setStroke() from instance, however I have no idea how to do it. Please tell me how to do it, if you know. Thank you for your kindeness.
class UpTriangleView: UIView {
override func drawRect(rect: CGRect) {
self.backgroundColor = UIColor.clearColor()
// Get Height and Width
let layerHeight = self.layer.frame.height
let layerWidth = self.layer.frame.width
// Create Path
let line = UIBezierPath()
// Draw Points
line.moveToPoint(CGPointMake(0, layerHeight))
line.addLineToPoint(CGPointMake(layerWidth, layerHeight))
line.addLineToPoint(CGPointMake(layerWidth/2, 0))
line.addLineToPoint(CGPointMake(0, layerHeight))
line.closePath()
// Apply Color
UIColor.grayColor().setStroke()
UIColor.grayColor().setFill()
line.lineWidth = 3.0
line.fill()
line.stroke()
// Mask to Path
let shapeLayer = CAShapeLayer()
shapeLayer.path = line.CGPath
self.layer.mask = shapeLayer
}
}
class QATableViewCell : UITableViewCell{
#IBOutlet weak var upTriangleView: UpTriangleView!
}

Answer 1

Add a property to your UpTriangleView that is the color you want to draw it. Implement didSet and call setNeedsDisplay() if the color is set:
class UpTriangleView: UIView {
var color = UIColor.gray {
didSet {
self.setNeedsDisplay()
}
}
override func draw(_ rect: CGRect) {
self.backgroundColor = .clear
// Get Height and Width
let layerHeight = self.layer.bounds.height
let layerWidth = self.layer.bounds.width
// Create Path
let line = UIBezierPath()
// Draw Points
line.move(to: CGPoint(x: 0, y: layerHeight))
line.addLine(to: CGPoint(x: layerWidth, y: layerHeight))
line.addLine(to: CGPoint(x: layerWidth/2, y: 0))
line.addLine(to: CGPoint(x: 0, y: layerHeight))
line.close()
// Apply Color
color.setStroke()
color.setFill()
line.lineWidth = 3.0
line.fill()
line.stroke()
// Mask to Path
let shapeLayer = CAShapeLayer()
shapeLayer.path = line.cgPath
self.layer.mask = shapeLayer
}
}
Now, demo it in a Playground (see picture below for results):
let utv = UpTriangleView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
utv.color = .yellow // now triangle is yellow
utv.color = .red // now triangle is red
setNeedsDisplay will tell iOS your view needs redrawing, and drawRect will be called again using the newly set color.