MultipeerConnectivity | Xamarin.iOS Multipeer Connectivity Example : Discovery & Chat | iOS library

Allright so this is a bug. I reproduced your issue using the python docker container, only installing the latest tensorflow. What fixed it, was renaming code.py to test.py (or anything else for that matter). This means this this is for sure a tensorflow issue. During import tensorflow, python will for some reason also import your code.py. Will you file an issue or should I?

It seems MCAdvertiserAssistant and MCBrowserViewController are not updated for latest versions of iOS & Swift, hence they're not working properly.

I solved it by using MCNearbyServiceAdvertiser instead of MCAdvertiserAssistant and MCNearbyServiceBrowser instead of MCBrowserViewController. Note that by using these classes, you'll need to perform basic operations yourself such as listing founded devices, showing and handling invitation alert.. etc.

You can use these classes as below.

Definition:

In an attempt to remove sources of doubt, I've gone through various exercises such as adding a delay before each change in a child progress, twiddling various numbers, and even translating the whole thing into Objective-C to make sure this isn't some sort of Swift numerics issue:

Your understanding is almost correct until iOS 13, which added GATT over BR/EDR ("Classic"). There's also L2CAP since iOS 11.

There is no app access to other Bluetooth profiles. The device supports them, but there is no SDK.

JSON does not encode types. It just encodes data. It's up to you to decide how to map that data to types in your system. If you need to tell the other side what the type is, you'll need to encode that in the JSON.

If you're only working with Cocoa devices (iOS/macOS), you may want to use NSSecureCoding and NSKeyedArchiver rather than JSON. This format does send type information, and is designed for sending full objects (rather than just data) between programs. For an example project, see https://www.objc.io/issues/8-quadcopter/the-quadcopter-client-app/.

I (finally) figured it out. MultipeerConnectivity needs a run loop. This is not in the documentation.

I assumed that the MultipeerConnectivity API created the threads and/or loops it needed upon the method call [browser startBrowsingForPeers]. It does not.

Nowhere in this code is a run loop started. Also, interestingly enough, using a NSThread directly doesn't start a run loop, even though it's implied that it will:

Your application neither creates or explicitly manages NSRunLoop objects. Each NSThread object—including the application’s main thread—has an NSRunLoop object automatically created for it as needed. If you need to access the current thread’s run loop, you do so with the class method currentRunLoop.

What will create a run loop (and start it) is CFRunLoopRun():

The current thread’s run loop runs in the default mode (see Default Run Loop Mode) until the run loop is stopped with CFRunLoopStop or all the sources and timers are removed from the default run loop mode.

What will stop it, then, is CFRunLoopStop(CFRunLoopRef rl):

This function forces rl to stop running and return control to the function that called CFRunLoopRun or CFRunLoopRunInMode for the current run loop activation.

Of course, CFRunLoopStop takes a CFRunLoopRef as an argument. You can get that by using CFRunLoopGetCurrent, just remember it's a reference and may expire at any time. I think you can be pretty sure that the run loop won't die while you're in the callback that's running in the run loop. But I wouldn't count on it sticking around afterwards. In fact, in this case, the whole point is to kill it at this point; so I expect it to go away.

Selector() : It receives string/ string-literal as a parameter. It was used previously and #selector is upgraded definition.

#selector : You are trying to pass a string in #selector whereas it takes Objective-C type function reference. Correct example is:

Well, at the end of the day the network layer is involved and there can be some delays. You won't have any influence on the method session(_ :peer:didChange:).

In my opinion you can only send one regular ping and if this does return longer than expected, the app assumes that the connection is dead. Of course, this can lead to false positives. So the app thinks the connection is dead, but the connection to the client is still active. The app must then be able to handle this.