How to detect if code is running in Main App or App Extension Target?

You can use a preprocessor macro:

In the project settings use the dropdown in the topbar to select your extension target:

Then:

1. Click Build Settings
2. Find (or search) Preprocessor Macros under Apple LLVM 6.0 - Preprocessing
3. Add TARGET_IS_EXTENSION or any other name of your choice in both the debug and release sections.

Then in your code:

#ifndef TARGET_IS_EXTENSION // if it's not defined    // Do your calls to UIApplication#endif

As Apple's documentation says:

When you build an extension based on an Xcode template, you get an extension bundle that ends in .appex.

So, we can use the following code:

if ([[[NSBundle mainBundle] bundlePath] hasSuffix:@".appex"]) {    // this is an app extension}// Swift versionif Bundle.main.bundlePath.hasSuffix(".appex") {    // this is an app extension}

The preprocessor macro will work mostly, but will not work in shared library (e.g. cocoapods or shared frameworks).

Alternatively you can use following code.

@implementation ExtensionHelpers+(BOOL) isAppExtension{    return [[[NSBundle mainBundle] executablePath] containsString:@".appex/"];}@end

This work by checking the bundle executablePath, as only App Extension has extension ".appex".