I'm developing a framework for iOS apps (a pod). I want to swizzle
application(_:didReceiveRemoteNotification:fetchCompletionHandler:)
with a method defined in my framework. this is my code:
class MyClass {
@objc
func myCustomizedMethod(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
// my code
}
private func swizzleDidReceiveRemoteNotification() {
guard let appDelegateClass = object_getClass(UIApplication.shared.delegate) else { return }
let originalSelector = #selector((appDelegateClass as! UIApplicationDelegate).application(_:didReceiveRemoteNotification:fetchCompletionHandler:))
let swizzledSelector = #selector(MyClass.self.myCustomizedMethod(_:didReceiveRemoteNotification:fetchCompletionHandler:))
guard let originalMethod = class_getInstanceMethod(appDelegateClass, originalSelector) else { return }
guard let swizzledMethod = class_getInstanceMethod(MyClass.self, swizzledSelector) else { return }
method_exchangeImplementations(originalMethod, swizzledMethod)
}
}
but when I run my code, it appears that originalMethod has nil value and so
class_getInstanceMethod(appDelegateClass, originalSelector)
returns nil. what I'm doing wrong? (please consider that I don't have access to AppDelegate, because as I said, I'm developing a framework)
this is the code that worked for me:
class MyClass {
@objc
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
// my code
}
private func swizzleDidReceiveRemoteNotification() {
let appDelegate = UIApplication.shared.delegate
let appDelegateClass = object_getClass(appDelegate)
let originalSelector = #selector(UIApplicationDelegate.application(_:didReceiveRemoteNotification:fetchCompletionHandler:))
let swizzledSelector = #selector(MyClass.self.application(_:didReceiveRemoteNotification:fetchCompletionHandler:))
guard let swizzledMethod = class_getInstanceMethod(MyClass.self, swizzledSelector) else {
return
}
if let originalMethod = class_getInstanceMethod(appDelegateClass, originalSelector) {
// exchange implementation
method_exchangeImplementations(originalMethod, swizzledMethod)
} else {
// add implementation
class_addMethod(appDelegateClass, swizzledSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))
}
}
}