If you are running into the error of “Use of undeclared type” trying to use an Objective-C object in Swift, then the problem might be due to the bridging header between Swift and Objective-C not actually working properly. When you use the bridging header between Swift and Objective-C to import Objective-C objects into Swift the objects aren’t always imported properly all the time. Instead this “problematic” import may lead to some Objective-C objects being imported into the Swift class you are using and not others, leading to the “Use of undeclared type” problem with Objective-C objects.
How to resolve this when you are having this problem is to import the framework again from Swift. This will do a proper import of the Objective-C class and the “Use of undeclared type” problem should disappear from your iOS program. See the video below for more details.