CODEWITHSUNDEEP
objective-cswiftclassenums
bhartsb
bhartsb

Reputation: 1356

Using Swift Class and Enum from Objective-C

I've included a set of swift classes and their swift dependencies into my Objective-C project. I've already done this for other swift libraries, so things like the Obj-C Generated Interface Header are already present.

This is the class I wish to use:

    @objc public class StatusBarNotificationBanner: BaseNotificationBanner 
    {
    override init(style: BannerStyle) {
        super.init(style: style)
        bannerHeight = 20.0

        titleLabel = MarqueeLabel()
        titleLabel?.animationDelay = 2
        titleLabel?.type = .leftRight
        titleLabel!.font = UIFont.systemFont(ofSize: 12.5, weight: UIFontWeightBold)
        titleLabel!.textAlignment = .center
        titleLabel!.textColor = .white
        addSubview(titleLabel!)

        titleLabel!.snp.makeConstraints { (make) in
            make.top.equalToSuperview()
            make.left.equalToSuperview().offset(5)
            make.right.equalToSuperview().offset(-5)
            make.bottom.equalToSuperview()
        }

        updateMarqueeLabelsDurations()
    }

    public convenience init(title: String, style: BannerStyle = .info) {
        self.init(style: style)
        titleLabel!.text = title
    }

    public convenience init(attributedTitle: NSAttributedString, style: BannerStyle = .info) {
        self.init(style: style)
        titleLabel!.attributedText = attributedTitle
    }

    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

}

This is how one would use the class in swift:

let banner = StatusBarNotificationBanner(title: title, style: .success)
banner.show()

How in Obj-C would I instantiate StatusBarNotificationBanner and call its show() method?

Also, how do I pass the enum parameter style?

This is the enum:

public enum BannerStyle {
    case danger
    case info
    case none
    case success
    case warning
}

I guess that the enum needs to take the form:

@objc public enum BannerStyle: Int {
    case danger
    case info
    case none
    case success
    case warning
}

But I still don't know how to pass it as a param in Obj-C and I'm not understanding why the Int has to be specified? Isn't the enum implicitly Int?

Upvotes: 1

Views: 3118

Answers (1)

matt
matt

Reputation: 535944

Isn't the enum implicitly Int?

Not really. Objective-C cannot see a Swift enum at all. In Swift, an enum is an object type. Objective-C has no knowledge whatever of any such object type; its only objects are classes. (In Objective-C, enums are just numbers with names.) Therefore, neither a Swift enum type, nor a method that takes or produces a Swift enum, nor a Swift enum property, is exposed to Objective-C

However, in the special case where you say @objc enum BannerStyle: Int, it is translated into an Objective-C enum for you. So, in Objective-C, names such as BannerStyleDanger and BannerStyleInfo will spring to life. But they will just be integers.

Upvotes: 5

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