CODEWITHSUNDEEP
iosswift
Ian Warburton
Ian Warburton

Reputation: 15676

Layer zPosition has no effect

Three layers are given the same parent, but the zPosition value on the first layer to be added has no effect - it remains at the back. Why is this? The book I'm reading says that the position in the sublayers array can be overridden with the zPosition value.

import UIKit
import PlaygroundSupport

extension CGRect {
    init(_ x:CGFloat, _ y:CGFloat, _ w:CGFloat, _ h:CGFloat) {
        self.init(x:x, y:y, width:w, height:h)
    }
}

let v0 = UIView(frame: CGRect(0, 0, 500, 500))
v0.backgroundColor = .white

let v1 = UIView(frame: v0.frame)

let lay1 = CALayer()
lay1.backgroundColor = UIColor(red: 1, green: 0.4, blue: 1, alpha: 1).cgColor
lay1.frame = CGRect(113, 111, 132, 194)
lay1.zPosition = 100
v1.layer.addSublayer(lay1)

let lay2 = CALayer()
lay2.backgroundColor = UIColor(red: 0.5, green: 1, blue: 0, alpha: 1).cgColor

lay2.frame = CGRect(41, 56, 132, 194)
v1.layer.addSublayer(lay2)

let lay3 = CALayer()
lay3.backgroundColor = UIColor(red: 1, green: 0, blue: 0, alpha: 1).cgColor
lay3.frame = CGRect(43, 197, 160, 230)
v1.layer.addSublayer(lay3)

v0.addSubview(v1)

PlaygroundPage.current.liveView = v0

Upvotes: 2

Views: 1368

Answers (2)

Ian Warburton
Ian Warburton

Reputation: 15676

Code works as expected in an app. Seems that it's an issue with Playground.

Upvotes: 0

Puneet Sharma
Puneet Sharma

Reputation: 9484

I think your code is working as expected. I just changed the colors of the view to 

lay1.backgroundColor = UIColor.green.cgColor
lay2.backgroundColor = UIColor.blue.cgColor
lay3.backgroundColor = UIColor.red.cgColor

This is the output. You can see green view(lay1) which has z position is at the top.

enter image description here

Also , had fun playing with literals here:

enter image description here

Upvotes: 3

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