Getting frame of programmatically created subviews - ios

Question

I have a programmatically created subviews, view1. I am adding some UIButtons to it, but the measurements of these buttons depend on view1.frame.height. However, I can only seem to get the value in viewDidAppear, which obviously is not what I want. Moreover, if I put my addButtons() function in viewDidLayoutSubviews, I get an infinite loop. The results of putting addButtons() in various UIViewController functions is as follows (in comments):
override func viewDidLoad() {
super.viewDidLoad()
addView1()
}
override func viewDidLayoutSubviews(){
print(view1.frame.height) // 0.0 first time it is called, 74.0, which is right, the second time it is called, but I got into an infinite loop
//addButtons() -> infinite loop
}
override func viewWillAppear(animated: Bool) {
print(view1.frame.height) //0.0
}
override func viewDidAppear(animated: Bool) {
print(view1.frame.height) //74.0, the value I want, but obviously not where I want it
}
My addButtons() looks like this:
func addButtons(){
let mon = UIButton()
let tue = UIButton()
let wed = UIButton()
let thu = UIButton()
let fri = UIButton()
let sat = UIButton()
let sun = UIButton()
let buttonsArray = ["mon": mon, "tue": tue, "wed": wed, "thu": thu, "fri": fri, "sat": sat, "sun": sun]
let daysArray1 = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]
var daysArray2 = ["mon": "M", "tue":"T", "wed": "W", "thu": "T", "fri": "F", "sat": "S", "sun": "S"]
let buttonSide = view1.frame.height * 0.6
let distance = (view1.frame.width - buttonSide * 7) / 8.0
var count = 0
for day in daysArray1{
let offSet = (buttonSide ) * CGFloat(count) + distance * CGFloat(count + 1)
let centerX = (buttonSide / 2) + offSet
buttonsArray[day]!.setTitle(daysArray2[day], forState: .Normal)
buttonsArray[day]!.translatesAutoresizingMaskIntoConstraints = false
buttonsArray[day]!.layer.cornerRadius = 5
view1.addSubview(buttonsArray[day]!)
view1.addConstraint(NSLayoutConstraint(item: buttonsArray[day]!, attribute: NSLayoutAttribute.CenterY, relatedBy: .Equal, toItem: view1, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0))
view1.addConstraint(NSLayoutConstraint(item: buttonsArray[day]!, attribute: NSLayoutAttribute.CenterX, relatedBy: .Equal, toItem: view1, attribute: NSLayoutAttribute.Left, multiplier: 1, constant: centerX))
view1.addConstraint(NSLayoutConstraint(item: buttonsArray[day]!, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: buttonSide))
view1.addConstraint(NSLayoutConstraint(item: buttonsArray[day]!, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: buttonSide))
count += 1
}

Answer 1

Every time you add a button to your view the system calls viewDidLayoutSubviews which you keep adding buttons and the system keeps calling viewDidLayoutSubviews. You should add your buttons when viewDidLoad().
To match the height of the view you can:
Pin all buttons to Trailing and Leading edge of the view
Pin the first button's Top with view's Top Edge
Pin the last button's Bottom with view's Bottom
Pin each button's Top with the previous button's Bottom edge (given is not the first button)
Constraint all buttons .Height to match view's .Height with a multiplier of 0.6
This is an example I did using PureLayout
let someView = UIView(frame: CGRectZero)
view.addSubview(someView)
var prev: UIButton?
for i in 0..<6 {
let button = UIButton(frame: CGRectZero)
button.setBackgroundColor(UIColor.randomColor(), forUIControlState: .Normal)
someView.addSubview(button)
button.autoPinEdgeToSuperviewEdge(.Trailing)
button.autoPinEdgeToSuperviewEdge(.Leading)
button.autoMatchDimension(.Height, toDimension: .Height, ofView: someView, withMultiplier: 0.6)
if let previous = prev {
button.autoPinEdge(.Top, toEdge: .Bottom, ofView: previous)
} else {
button.autoPinEdgeToSuperviewEdge(.Top)
}
prev = button
}
someView.autoPinEdgeToSuperviewEdge(.Trailing)
someView.autoPinEdgeToSuperviewEdge(.Leading)
someView.autoPinEdgeToSuperviewEdge(.Top)
someView.autoSetDimension(.Height, toSize: 100)
UPDATE(equal horizontal spacing)
OK based your comment, I got that you also need equal spacing between buttons as well as the side edges of the parent container. where is a full working view controller class:
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let wrapper = UIView(frame: CGRectZero)
view.addSubview(wrapper)
wrapper.backgroundColor = UIColor.redColor()
var previous: (button: UIButton, spacer: UIView)?
for day in ["M", "T", "W", "T", "F", "S", "S"] {
let button = UIButton(frame: CGRectZero)
let spacer = UIView(frame: CGRectZero)
button.setTitle(day, forState: .Normal)
button.backgroundColor = UIColor.grayColor()
button.translatesAutoresizingMaskIntoConstraints = false
spacer.translatesAutoresizingMaskIntoConstraints = false
wrapper.addSubview(button)
wrapper.addSubview(spacer)
//set height 60% of wrapper
wrapper.addConstraint(NSLayoutConstraint(
item: button,
attribute: .Height,
relatedBy: .Equal,
toItem: wrapper,
attribute: .Height,
multiplier: 0.6,
constant: 0))
//set width same has height
wrapper.addConstraint(NSLayoutConstraint(
item: button,
attribute: .Height,
relatedBy: .Equal,
toItem: button,
attribute: .Width,
multiplier: 1,
constant: 0))
//pin button leading with spacer trailing
wrapper.addConstraint(NSLayoutConstraint(
item: button,
attribute: .Leading,
relatedBy: .Equal,
toItem: spacer,
attribute: .Trailing,
multiplier: 1,
constant: 0))
//pin spacer trailing with button leading
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Trailing,
relatedBy: .Equal,
toItem: button,
attribute: .Leading,
multiplier: 1,
constant: 0))
//align button to center
wrapper.addConstraint(NSLayoutConstraint(
item: button,
attribute: .CenterY,
relatedBy: .Equal,
toItem: wrapper,
attribute: .CenterY,
multiplier: 1,
constant: 0))
if let previous = previous {
//pin spacer Leading with previous button trailing
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Leading,
relatedBy: .Equal,
toItem: previous.button,
attribute: .Trailing,
multiplier: 1,
constant: 0))
//pin previous button's Trailing with spacer Leading
wrapper.addConstraint(NSLayoutConstraint(
item: previous.button,
attribute: .Trailing,
relatedBy: .Equal,
toItem: spacer,
attribute: .Leading,
multiplier: 1,
constant: 0))
//set spacer's width same as previous spacer
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Width,
relatedBy: .Equal,
toItem: previous.spacer,
attribute: .Width,
multiplier: 1,
constant: 0))
} else {
//this is the first item, pin the spacer Leading to wrapper Leading
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Leading,
relatedBy: .Equal,
toItem: wrapper,
attribute: .Leading,
multiplier: 1,
constant: 0))
}
previous = (button: button, spacer: spacer)
}
// last spacer
if let previous = previous {
let spacer = UIView(frame: CGRectZero)
spacer.translatesAutoresizingMaskIntoConstraints = false
wrapper.addSubview(spacer)
//pin spacer Leading with previous button trailing
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Leading,
relatedBy: .Equal,
toItem: previous.button,
attribute: .Trailing,
multiplier: 1,
constant: 0))
//pin previous button's Trailing with spacer Leading
wrapper.addConstraint(NSLayoutConstraint(
item: previous.button,
attribute: .Trailing,
relatedBy: .Equal,
toItem: spacer,
attribute: .Leading,
multiplier: 1,
constant: 0))
//set spacer's width same as previous spacer
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Width,
relatedBy: .Equal,
toItem: previous.spacer,
attribute: .Width,
multiplier: 1,
constant: 0))
//pin spacer's Trailing with wrappper Trailing
wrapper.addConstraint(NSLayoutConstraint(
item: spacer,
attribute: .Trailing,
relatedBy: .Equal,
toItem: wrapper,
attribute: .Trailing,
multiplier: 1,
constant: 0))
}
wrapper.frame = CGRect(x: 0, y: 100, width: 320, height: 40)
}
}