UIView.Type does not have member named bounds

Question

I am simply trying to set two var to the bounds.size.width and .height of a view.

import UIKit

class BKView: UIView {

    var maxX: CGFloat = bounds.size.width
    var maxY: CGFloat = bounds.size.height

}

However Xcode fails saying with error: 'BKView.Type' does not have member named 'bounds'.

Any suggestions?

Answer 1

It's a terribly-worded compiler error, but what it means is that you can't give properties default values based on other properties of the class (or superclass). Here's a simpler variant of what's happening:

class A {
    let x: Int

    init(x: Int) {
        self.x = x
    }
}

class B: A {
    // error: 'B.Type' does not have a member named 'x'
    let y = x
}

You'll have to initialize maxX and maxY inside an init method instead, after you've called super.init (because only after that are you allowed to access the superclass's properties).

Answer 2

@Airspeed Velocity gives a good explanation. I wanted to add that alternatively you could use lazy initialisation. For example:

class BKView: UIView {
    lazy var maxX: CGFloat = self.bounds.size.width
    lazy var maxY: CGFloat = self.bounds.size.height
}

For more information see: http://mikebuss.com/2014/06/22/lazy-initialization-swift/

Answer 3

When creating a view, It is needed to define some default initialiser methods. Define a class as follows:

class TestView: UIView {

    var maxX : CGFloat?
    var maxY : CGFloat?

    override init() {

        super.init()
        initializeBounds()
    }

    required init(coder aDecoder: NSCoder) {

        super.init(coder: aDecoder)
        initializeBounds()

    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        initializeBounds()
    }

    func initializeBounds()
    {
        maxX = self.bounds.size.width
        maxY = self.bounds.size.height

    }

    // Only override drawRect: if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.
    override func drawRect(rect: CGRect) {
        // Drawing code

        println("maxX: \(maxX!) maxY: \(maxY!)")
    }


}

Whenever the TestView is initialised by Storyboard or Coding, the TestView 's properties getting initialised.

After adding the view to your view controller's view as follows:

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.


        var testView : TestView = TestView(frame: CGRectMake(10.0, 10.0, 100.0, 50.0))
        testView.backgroundColor = UIColor.redColor()
        self.view.addSubview(testView)

}

The log gives as follows:

TestView: maxX: 100.0 maxY: 50.0

To avoid replication of code, initializeBounds() is defined and called in TestView 's initializers:

Answer 4

Use self.bounds.size.width and self.bounds.size.height . You should assign the properties maxX and maxY values in an initializer or some other function, instead of inline. Example:

init(frame: CGRect) {
    super.init(frame: frame)
    maxX = self.bounds.size.width
    maxY = self.bounds.size.height
}