在测试了几十个解决方案之后，我发现以下解决方案可以可靠地工作：

/**
 Returns true if the code is being executed as part of the Interface Builder IBDesignable rendering,
 so not for testing the app but just for rendering the controls in the IB window. You can use this
 to do special processing in this case.

* /

public func runningInInterfaceBuilder() -> Bool {
    //get the mainbundles id
    guard let bundleId = NSBundle.mainBundle().bundleIdentifier else {
        //if we don't have a bundle id we are assuming we are running under IBDesignable mode
        return true
    }
    //when running under xCode/IBDesignable the bundle is something like
    //com.apple.InterfaceBuilder.IBCocoaTouchPlugin.IBCocoaTouchTool
    //so we check for the com.apple. to see if we are running in IBDesignable rendering mode
    //if you are making an app for apple itself this would not work, but we can live with that :)
    return bundleId.rangeOfString("com.apple.") != nil
}

SWIFT 4版

/**
     Returns true if the code is being executed as part of the Interface Builder IBDesignable rendering,
     so not for testing the app but just for rendering the controls in the IB window. You can use this
     to do special processing in this case.
     */
    public func runningInInterfaceBuilder() -> Bool {
        //get the mainbundles id
        guard let bundleId = Bundle.main.bundleIdentifier else {
            //if we don't have a bundle id we are assuming we are running under IBDesignable mode
            return true
        }
        //when running under xCode/IBDesignable the bundle is something like
        //com.apple.InterfaceBuilder.IBCocoaTouchPlugin.IBCocoaTouchTool
        //so we check for the com.apple. to see if we are running in IBDesignable rendering mode
        //if you are making an app for apple itself this would not work, but we can live with that :)
        return bundleId.contains("com.apple.")
    }