Add Button to UIView Created Programmatically - ios

Question

I created UIView and Button programmatically
var width = self.view.frame.width - 8
var height = width/8
newView.frame = CGRectMake(4, 39, width, height)
newView.backgroundColor = UIColor.greenColor()
self.view.addSubview(newView)
var button = UIButton.buttonWithType(UIButtonType.System) as! UIButton
button.frame = newView.frame
button.backgroundColor = UIColor.whiteColor()
button.addTarget(self, action: "buttonAction:", forControlEvents: UIControlEvents.TouchUpInside)
button.setTitle(" All Hospitals/Clinics", forState: UIControlState.Normal)
button.setTitleColor(UIColor.blackColor(), forState: .Normal)
button.contentHorizontalAlignment = UIControlContentHorizontalAlignment.Left
newView.addSubview(button)
I want the button to be inside the UIView, and to have exactly the same location, width and height of UIView
but the result is this
What is wrong with my code ?
Thanks in advance

Answer 1

The issue is caused by this line of code:
button.frame = newView.frame // Equivalent to button.frame = CGRectMake(4, 39, width, height)
In your current implementation the x position of button is 4 and y position is 39, that's why you are getting the result like that way. You need to specify the button frame relative to the newView.
Change the button frame setting code to:
button.frame = CGRectMake(0, 0, width, height)

Answer 2

You should use bounds instead of the frame of the view.
button.frame = newView.bounds
Bounds returns the CGRect of the view coordinates in its own coordinate space, while frame returns the same but in it's parent's coordinate space.
So newView.bounds would return a CGRect like (0,0,width_of_newView,height_of_newview)

Answer 3

your button frame is wrong.
when you declared x and y property of a frame, it is related to its superview.
since you declare your button frame as (4, 39, width, height) it will be placed on coordinate x = 4, y = 39 in view's frame which is exactly like your picture.
if you want to make it like your view, change x and y to 0.

Answer 4

you can use Anchor
lazy var testButton: UIButton = {
let button = UIButton()
button.translatesAutoresizingMaskIntoConstraints = false
button.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
button.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
button.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
button.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
return button
}()
override func viewDidLoad() {
self.view.addSubview(testButton)
}