UIPreviewActionItem for SFSafariViewController through delegation not subclassing

README.md

Adding UIPreviewActionItem to SFSafariViewController might be a tedious task. This extansion should help.

let vc = SFSafariViewController(initialURL: url, entersReaderIfAvailable: true)
vc.previewActionItemsDelegate = self

When presenting SFSafariViewController use convenience initializer that will store original URL for later, it'll make custom action requiring original URL easier. But it's not mandatory.

Here is the delegate implementation, this is where we might want to use initialURL

func safariViewControllerPreviewActionItems(controller: SFSafariViewController) -> [UIPreviewActionItem] {
    var actions: [UIPreviewActionItem] = []
    if let url = controller.initialURL {
        // Only if we know initialURL
        let action1 = UIPreviewAction(title: "Action 1", style: .Default, handler: { action, controller in
            print("action1 for initial URL \(url)")
        })
        actions.append(action1)
    }
    let action2 = UIPreviewAction(title: "Action 2", style: .Default, handler: { action, controller in
        print("action1")
    })
    actions.append(action2)
    return actions
}

SFSafariViewController+PreviewActionItems.swift

import SafariServices
import ObjectiveC

private struct AssociatedKeys {
    static var PreviewActionItemsDelegateName = "previewActionItemsDelegate"
    static var InitialURL = "initialURL"
}

extension SFSafariViewController {
    private(set) public var initialURL: NSURL? {
        set {
            objc_setAssociatedObject(self, &AssociatedKeys.InitialURL, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
        get {
            return objc_getAssociatedObject(self, &AssociatedKeys.InitialURL) as? NSURL
        }
    }
    
    public convenience init(initialURL: NSURL, entersReaderIfAvailable: Bool) {
        self.init(URL: initialURL, entersReaderIfAvailable: entersReaderIfAvailable)
        self.initialURL = initialURL
    }
}


// Preview action items
extension SFSafariViewController {
    
    weak var previewActionItemsDelegate: SFSafariViewControllerPreviewActionItemsDelegate? {
        set {
            objc_setAssociatedObject(self, &AssociatedKeys.PreviewActionItemsDelegateName, newValue, .OBJC_ASSOCIATION_ASSIGN)
        }
        get {
            return objc_getAssociatedObject(self, &AssociatedKeys.PreviewActionItemsDelegateName) as? SFSafariViewControllerPreviewActionItemsDelegate
        }
    }
    
    public override func previewActionItems() -> [UIPreviewActionItem] {
        return previewActionItemsDelegate?.safariViewControllerPreviewActionItems(self) ?? []
    }
}

public protocol SFSafariViewControllerPreviewActionItemsDelegate: class {
    func safariViewControllerPreviewActionItems(controller: SFSafariViewController) -> [UIPreviewActionItem]
}

All the API I used is objective c API. You can literally rewrite it in objective c as is and it should work