类不符合NSObjectProtocol

问题描述：

我收到一个错误，指出我的课程不符合NSObjectProtocol，我不知道这意味着什么。我已经从WCSessionDelegate实现了所有功能，所以这不是问题。有人知道问题出在哪里吗？谢谢！

I get an error that my class doesn't conform the NSObjectProtocol, I don't know what this means. I have implemented all the function from the WCSessionDelegate so that is not the problem. Does somebody know what the issue is? Thanks!

import Foundation
import WatchConnectivity

class BatteryLevel: WCSessionDelegate {


    var session: WCSession? {
        didSet {
            if let session = session {
                session.delegate = self
                session.activate()
            }
        }
    }

    var batteryStatus = 0.0;

    func getBatteryLevel(){
        if WCSession.isSupported() {
            // 2
            session = WCSession.default()
            // 3
            session!.sendMessage(["getBatteryLevel": ""], replyHandler: { (response) -> Void in
                if (response["batteryLevel"] as? String) != nil {
                    self.batteryStatus = (response["batteryLevel"] as? Double)! * 100
                }
            }, errorHandler: { (error) -> Void in
                // 6
                print(error)
            })
        }}


    func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
    }

    func session(_ session: WCSession, didReceiveMessage message: [String : Any]) {
    }
}

答

请参见

See Why in swift we cannot adopt a protocol without inheritance a class from NSObject?

简而言之， WCSessionDelegate 本身是从 NSObjectProtocol 继承的也可以实现该协议中的方法。实现这些方法的最简单方法是子类 NSObject ：

In short, WCSessionDelegate itself inherits from NSObjectProtocol therefore you need to implement methods in that protocol, too. The easiest way to implement those methods is to subclass NSObject:

class BatteryLevel: NSObject, WCSessionDelegate

请注意，您在此处处理的是Obj-C API。

Note that you are dealing with Obj-C APIs here.

类不符合NSObjectProtocol

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