有什么解决方法可以快速将存储的属性放入扩展中？

Question

I'm creating my project all in code and it was a bit confusing and difficult to read because there were several lines just to set up UIElements in my code...

so I tried to insert this bulky part into an extension and got an error saying that stored properties can't go into extensions, after that my solution was as follows...

weak var centraliseButton: UIButton!
weak var infoButton: UIButton!
weak var seeFireButton: UIButton!
weak var locatManager: CLLocationManager!
weak var mapkitView: MKMapView!
weak var containerViewForInfoButton: UIView!
weak var containerViewForSeeFireButton: UIView!

and then I set up evertyhing in an function in a extension file and call this function inside viewDidLoad() , but again I got tons of runtime errors and nils because I access self inside some of these properties and they were lazy var before, so my last solution was the following:

lazy var centraliseButton: UIButton = UIButton()
lazy var infoButton: UIButton = UIButton()
lazy var seeFireButton: UIButton = UIButton()
lazy var locatManager: CLLocationManager = CLLocationManager()
lazy var mapkitView: MKMapView = MKMapView()
lazy var containerViewForInfoButton: UIView = UIView()
lazy var containerViewForSeeFireButton: UIView = UIView()

and set everything inside the function in a extension, it worked I got no errors but it looks like a bad solution to me, I had to initialize all of them with a 'dummy' value because lazy var require being initialized right away so...

Is it a bad practise? Is there any better way to accomplish that?

thank you in advance for the answers!

Answer 1

I assume you have a really good reason for not just storing these properties in the class itself.

So the way to work around it is to use objc_getAssociatedObject and objc_setAssociatedObject.

For example, in your extension you could put:

struct AssociatedKeys 
{
    static var infoButton: UInt8 = 0
}

private(set) var infoButton: UIButton? 
{
    get 
    {
        guard let value = objc_getAssociatedObject(self, &AssociatedKeys.infoButton) as? UIButton else 
        {
            return nil
        }
        return value
    }
    set(newValue) 
    {
        objc_setAssociatedObject(self, &AssociatedKeys.infoButton, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    }
}