WCSession with WCSessionDelegate Summary

WCSession is a class in the WatchConnectivity framework that allows for communication between an iOS app and a watchOS app running on an Apple Watch. This class provides methods for sending data between the two devices, and for managing the state of the communication session.

WCSessionDelegate is a protocol that defines methods that can be implemented by an object to handle events related to communication sessions between an iOS app and a watchOS app using WCSession. The methods in this protocol are called by the WCSession object in response to various events, such as when a session is activated, deactivated, or receives a message.

Some key methods of WCSession include:

activate()
This method activates the session between the iOS app and the watchOS app. This method should be called before attempting to send or receive any data.

sendMessage(_:replyHandler:errorHandler:)
This method sends a message from the iOS app to the watchOS app, along with optional reply and error handlers to handle the response from the watchOS app.

updateApplicationContext(_:)
This method sends a dictionary of application context data from the iOS app to the watchOS app, which can be used to update the watchOS app's user interface or state.

transferUserInfo(_:)
This method sends a dictionary of user information data from the iOS app to the watchOS app, which can be used to update the watchOS app's data model or state.

Some key methods of WCSessionDelegate include:

session(_:activationDidCompleteWith:error:)
This method is called when the session between the iOS app and the watchOS app is activated or deactivated. The error parameter is nil if the session was activated successfully, or contains an error object if activation failed.

session(_:didReceiveMessage:replyHandler:)
This method is called when the watchOS app receives a message from the iOS app. The replyHandler parameter is a closure that can be called by the watchOS app to send a response back to the iOS app.

session(_:didReceiveApplicationContext:)
This method is called when the watchOS app receives updated application context data from the iOS app.

session(_:didReceiveUserInfo:)
This method is called when the watchOS app receives updated user information data from the iOS app.

Overall, WCSession and WCSessionDelegate provide a powerful framework for communication between iOS and watchOS apps, allowing for a seamless user experience across both devices.