EXC_BAD_INSTRUCTION when trying to pass data to UIViews - ios

Question

I created a call of a UIView in which I draw a graph. I am trying to pass it new data and have it update.
When I run the app on the simulator and click the tab in which the the controller housing the view is in, I receive this error:
Thread 1: EXC_BAD_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0)
at the line:
let maxValue = graphPoints.maxElement()
Here is my code for the view:
#IBDesignable class GraphView: UIView {
var graphPoints :[Int]!
override init(frame: CGRect) {
super.init(frame: frame)
}
init(graphPoints: [Int]) {
self.graphPoints = graphPoints
super.init(frame: CGRectZero)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
#IBInspectable var startColor: UIColor = UIColor.redColor()
#IBInspectable var endColor: UIColor = UIColor.greenColor()
override func drawRect(rect: CGRect) {
let width = rect.width
let height = rect.height
//set up background clipping area
let path = UIBezierPath(roundedRect: rect,
byRoundingCorners: UIRectCorner.AllCorners,
cornerRadii: CGSize(width: 8.0, height: 8.0))
path.addClip()
//2 - get the current context
let context = UIGraphicsGetCurrentContext()
let colors = [startColor.CGColor, endColor.CGColor]
//3 - set up the color space
let colorSpace = CGColorSpaceCreateDeviceRGB()
//4 - set up the color stops
let colorLocations:[CGFloat] = [0.0, 1.0]
//5 - create the gradient
let gradient = CGGradientCreateWithColors(colorSpace,
colors,
colorLocations)
//6 - draw the gradient
var startPoint = CGPoint.zeroPoint
var endPoint = CGPoint(x:0, y:self.bounds.height)
CGContextDrawLinearGradient(context,
gradient,
startPoint,
endPoint,
.DrawsBeforeStartLocation)
//calculate the x point
let rightMargin:CGFloat = 40
let leftMargin : CGFloat = 10
let columnXPoint = { (column:Int) -> CGFloat in
//Calculate gap between points
let spacer = (width - rightMargin - leftMargin - 4) /
CGFloat((self.graphPoints.count - 1))
var x:CGFloat = CGFloat(column) * spacer
x += leftMargin + 2
print(x)
return x
}
// calculate the y point
let topBorder:CGFloat = 30
let bottomBorder:CGFloat = 50
let graphHeight = height - topBorder - bottomBorder
let maxValue = graphPoints.maxElement()
let columnYPoint = { (graphPoint:Int) -> CGFloat in
var y:CGFloat = CGFloat(graphPoint) /
CGFloat(maxValue!) * graphHeight
y = graphHeight + topBorder - y // Flip the graph
print(y)
return y
}
// draw the line graph
UIColor.whiteColor().setFill()
UIColor.whiteColor().setStroke()
//set up the points line
let graphPath = UIBezierPath()
//go to start of line
graphPath.moveToPoint(CGPoint(x:columnXPoint(0), y:columnYPoint(graphPoints[0])))
//add points for each item in the graphPoints array
//at the correct (x, y) for the point
for i in 1..<graphPoints.count {
let nextPoint = CGPoint(x:columnXPoint(i),
y:columnYPoint(graphPoints[i]))
graphPath.addLineToPoint(nextPoint)
}
//Create the clipping path for the graph gradient
//1 - save the state of the context (commented out for now)
CGContextSaveGState(context)
//2 - make a copy of the path
let clippingPath = graphPath.copy() as! UIBezierPath
//3 - add lines to the copied path to complete the clip area
clippingPath.addLineToPoint(CGPoint(
x: columnXPoint(graphPoints.count - 1),
y:height))
clippingPath.addLineToPoint(CGPoint(
x:columnXPoint(0),
y:height))
clippingPath.closePath()
//4 - add the clipping path to the context
clippingPath.addClip()
let highestYPoint = columnYPoint(maxValue!)
startPoint = CGPoint(x:leftMargin, y: highestYPoint)
endPoint = CGPoint(x:rightMargin, y:self.bounds.height)
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, .DrawsBeforeStartLocation)
CGContextRestoreGState(context)
//draw the line on top of the clipped gradient
graphPath.lineWidth = 2.0
graphPath.stroke()
//Draw the circles on top of graph stroke
for i in 0..<graphPoints.count {
var point = CGPoint(x:columnXPoint(i), y:columnYPoint(graphPoints[i]))
point.x -= 5.0/2
point.y -= 5.0/2
let circle = UIBezierPath(ovalInRect:
CGRect(origin: point,
size: CGSize(width: 5.0, height: 5.0)))
circle.fill()
}
//Draw horizontal graph lines on the top of everything
let linePath = UIBezierPath()
//top line
linePath.moveToPoint(CGPoint(x:leftMargin, y: topBorder))
linePath.addLineToPoint(CGPoint(x: width - rightMargin,
y:topBorder))
//center line
linePath.moveToPoint(CGPoint(x:leftMargin,
y: graphHeight/2 + topBorder))
linePath.addLineToPoint(CGPoint(x:width - rightMargin,
y:graphHeight/2 + topBorder))
//bottom line
linePath.moveToPoint(CGPoint(x:leftMargin,
y:height - bottomBorder))
linePath.addLineToPoint(CGPoint(x:width - rightMargin,
y:height - bottomBorder))
let color = UIColor(white: 1.0, alpha: 0.3)
color.setStroke()
linePath.lineWidth = 1.0
linePath.stroke()
}
And here is the code for my view controller in which I pass data to the view.
import UIKit
import QuartzCore
class ProgressViewController: UIViewController {
#IBOutlet weak var graphView: UIView!
var firstGraph : GraphView!
override func viewDidLoad() {
self.graphView = self.firstGraph
self.firstGraph = GraphView(graphPoints: [2240, 1983, 2171, 2017, 1842, 1992, 2347])
I'm new to Swift and I'm stumped on this problem after looking everywhere for an answer. Any help is appreciated.