Checking background color of view in swift - ios

Question

Say for example I have a white background, then on every time the view is touched, a blue box sized (60x60) is added to the screen. If i keep tapping all over the screen until the entire view becomes blue, how can I use code to notify the user using for example an alert controller saying that the view has now changed color completely.
if that made sense to anyone, I would appreciate any suggestions :)

Answer 1

As others have stated, the best approach is to hold a reference to a 2D array to correlate with the UI. I would approach this by first:
1) Create a subclass of UIView called overlayView. This will be the view overlay on top of your View Controllers' view. This subclass will override init(frame: CGRect). You may implement a NxM grid on initialization. You will also create and add the subviews as appropriate.
Example:
let boxWidth: CGFloat = 60
let boxHeight: CGFloat = 60
let boxFrame: CGRect = CGRectMake(0, 0, 600, 600)
override init(frame: CGRect) {
super.init(frame: boxFrame)
for i in 1 ... 10 { //row
for j in 1...10 { //column
let xCoordinate: CGFloat = CGFloat(CGFloat(i) * boxWidth)
let yCoordinate: CGFloat = CGFloat(CGFloat(j) * boxHeight)
let boxFrame: CGRect = CGRect(x: xCoordinate, y: yCoordinate, width: boxWidth, height: boxHeight)
var subView: UIView = UIView(frame: boxFrame)
subView.backgroundColor = UIColor.greenColor()
self.addSubview(subView)
}
}
}
2) Override touchesBegan(touches: NSSet, withEvent event: UIEvent) within overlayView. The implementation should look something like this:
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
let touch: UITouch = touches.anyObject() as UITouch
let touchLocation: CGPoint = touch.locationInView(self)
for subView in self.subviews {
if(CGRectContainsPoint(subView.frame, touchLocation)) {
subView.removeFromSuperview()
}
}
}
2a) You will also want to create a function to notify your 2D array that this subview as been removed. This will be called from within your if statement. In addition, this function will detect if the array is empty (all values set to false)
OR
2b) if you do not need a reference to the model (you do not care which boxes are tapped only that they're all gone), you can skip 2a and check if self.subviews.count == 0. If this is the case, you do not need a 2D array at all. If this condition passes, you can present an alert to the user as needed.
3) Create an overlayView in your main View Controller and add it as a subview.