無法分配給僅獲取對象的“localVc”的屬性？

Question

就像下面顯示的代碼一樣，為什么 swift 不允許分配只讀對象的屬性？ 只讀對象“localVc”具有設置寫入屬性“refreshGesture”。

public protocol HVSHomeVideoChildProtocol {
    var refreshGesture: UIPanGestureRecognizer! {get set}
}

class HVSHomeLocalVideoController: HVSHomeVideoChildProtocol {

    public var refreshGesture: UIPanGestureRecognizer!
}


typealias HVSHomeVideoController = (UIViewController & HVSHomeVideoChildProtocol)

@objc(HSAVideoHomeViewController)
class HSAVideoHomeViewController: UIViewController {
    
    var refreshGesture: UIPanGestureRecognizer!
    let singleLocalVc = HVSHomeLocalVideoController.init()  
    var localVc: HVSHomeVideoController {
        return singleLocalVc
    }


    public override func viewDidLoad() {
        super.viewDidLoad()
        refreshGesture = UIPanGestureRecognizer.init(target: self, action: #selector(refreshGestureAction(sender:)))
        localVc.refreshGesture = refreshGesture
    }

}

Answer 1

改變

public protocol HVSHomeVideoChildProtocol {
    var refreshGesture: UIPanGestureRecognizer! {get set}
}

到

public protocol HVSHomeVideoChildProtocol : AnyObject {
    var refreshGesture: UIPanGestureRecognizer! {get set}
}