da1lbi3 da1lbi3 - 4 months ago 63
Swift Question

Class does not conform NSObjectProtocol

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

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

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

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


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

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