iOS WatchKit - how to determine if your code is running in watch extension or the app

Question

With WatchKit you have your app that runs on the phone, and the watch app that runs as an extension.

If you create a library that contains common code to be used in both the phone app and the watch extension, is there a way to tell if the code is running in the phone app or the watch extension?

I.e.

if ([self isRunningInWatchExtension]) {
    NSLog(@"this is running on watch");
} else {
    NSLog(@"this is running on phone app");
}


- (BOOL)isRunningInWatchExtension {
    ???
}

Answer 1

I've accomplished this by checking the bundle identifier:

if ([[[NSBundle mainBundle] bundleIdentifier] isEqualToString:kAppBundleIdentifier]) {

    // Running in main app
}
else if ([[[NSBundle mainBundle] bundleIdentifier] isEqualToString:kWatchBundleIdentifier]) {

    // Running in extension
}

Answer 2

In target conditionals there are some conditionals that may help you,

#if TARGET_OS_WATCH
//do something for watch
#else
//do something for ios ==> assuming you only support two platforms
#endif

Answer 3

• This can be easy if you are calling any custom methods in your common framework class. You just need to add additional method parameters to method. And if you are calling this method from iOS app or Watchkit app then add appropriate key-value pair to dictionary for parameters. And compare this in your framework methods.

• To determine this from init or any other method then you can still get to know by this code,

  NSLog(@"%@",[NSThread callStackSymbols]);
  

So, you need to parse this string and get appropriate target names. If it is called by iOS app then you will get 'UIKit' string and from watch kit app extension you will get 'YourApp WatchKit Extension' string somewhere. You can also refer this SO answer for parsing this string and compare it - https://stackoverflow.com/a/9603733/602997