Touch Gesture Recognizer to clear screen of random function - swift

Question

I am building a collage in Xcode with a set background image and a random int function to display an image.
I tried using a tapGestureRecognizer to 1) display the random image and 2) clear the screen after using self.clearScreen. The images are displaying but they do not disappear when the next image is displayed.
import UIKit
import C4
class WorkSpace: CanvasController {
override func setup() {
var myRandomNumber: Int?
//Background Image
let background = Image("background")
background?.constrainsProportions = true
background?.width = self.canvas.width
background?.height = self.canvas.height
self.canvas.add(background)
canvas.addTapGestureRecognizer { (locations, center, state) in
self.clearScreen
myRandomNumber = random(below: 4)
}
}
if myRandomNumber == 1 {
let tree = Image("Tree")
tree?.constrainsProportions = true
tree?.width = self.canvas.width
tree?.origin = Point(0.0, self.canvas.height/2.0)
self.canvas.add(tree)
print("number1")
}
if myRandomNumber == 2 {
let boy = Image("boy")
boy?.constrainsProportions = true
boy?.width = self.canvas.width
boy?.origin = Point(0.0, self.canvas.height/2.0)
self.canvas.add(boy)
}
if myRandomNumber == 3 {
let woman = Image("woman")
woman?.constrainsProportions = true
woman?.width = self.canvas.width
woman?.height = self.canvas.height
self.canvas.add(woman)
}
}
}
I would like the screen to clear the pictures and replace with another.
func clearScreen() {
for view in self.view.subView {
view.removeFromSuperView()
}
}

Answer 1

After looking at the C4 pod docs:
Check the view hierarchy after adding to canvas
/// Adds a view to the end of the receiver’s list of subviews.
/// When working with C4, use this method to add views because it handles the addition of both UIView and View.
public func add<T>(_ subview: T?) {...}
And then try removing subviews with their supplied methods:
/// Unlinks the view from the receiver and its window, and removes it from the responder chain.
/// Calling this method removes any constraints that refer to the view you are removing, or that refer to any view in the
/// subtree of the view you are removing.
/// When working with C4, use this method to add views because it handles the removal of both UIView and View.
/// ````
/// let v = View(frame: Rect(0,0,100,100))
/// let subv = View(frame: Rect(25,25,50,50))
/// v.add(subv)
/// v.remove(subv)
/// ````
/// - parameter subview: The view to be removed.
public func remove<T>(_ subview: T?) {
if let v = subview as? UIView {
v.removeFromSuperview()
} else if let v = subview as? View {
v.view.removeFromSuperview()
} else {
fatalError("Can't remove subview of class `\(type(of: subview))`")
}
}