How to add swizzling method to UIApplication using Swift? - objective-c

Question

I have a code below trying to use swizzling method to UIApplication methods. But the methods not getting called. Meanwhile, I'm trying to add this code into a framework or a private pod.
extension UIApplication {
public override class func initialize() {
struct Static {
static var token: dispatch_once_t = 0
}
struct SwizzlingSelector {
let original:Selector
let swizzled:Selector
}
// make sure this isn't a subclass
if self !== UIApplication.self {
return
}
dispatch_once(&Static.token) {
let selectors = [
SwizzlingSelector(
original: Selector("application:didFinishLaunchingWithOptions:"),
swizzled: Selector("custome_application:didFinishLaunchingWithOptions:")
),
SwizzlingSelector(
original: Selector("applicationDidEnterBackground:"),
swizzled: Selector("custom_applicationDidEnterBackground:")
)
]
for selector in selectors {
let originalMethod = class_getInstanceMethod(self, selector.original)
let swizzledMethod = class_getInstanceMethod(self, selector.swizzled)
let didAddMethod = class_addMethod(self, selector.original, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))
if didAddMethod {
class_replaceMethod(self, selector.swizzled, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod))
} else {
method_exchangeImplementations(originalMethod, swizzledMethod);
}
}
}
}
// MARK: - Method Swizzling
public func custome_application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool {
print("is here")
return true
}
func custom_applicationDidEnterBackground(application: UIApplication) {
print("is herer")
}
}

Answer 1

I think you should implement this swizzling method in your AppDelegate but not as extension of UIApplication. Cause you swizzle your AppDelegate's methods but not UIApplication's methods.
extension YourAppDelegate {
public override class func initialize() {
struct Static {
static var token: dispatch_once_t = 0
}
struct SwizzlingSelector {
let original:Selector
let swizzled:Selector
}
// make sure this isn't a subclass
if self !== YourAppDelegate.self {
return
}
dispatch_once(&Static.token) {
let selectors = [
SwizzlingSelector(
original: Selector("application:didFinishLaunchingWithOptions:"),
swizzled: Selector("custome_application:didFinishLaunchingWithOptions:")
),
SwizzlingSelector(
original: Selector("applicationDidEnterBackground:"),
swizzled: Selector("custom_applicationDidEnterBackground:")
)
]
for selector in selectors {
let originalMethod = class_getInstanceMethod(self, selector.original)
let swizzledMethod = class_getInstanceMethod(self, selector.swizzled)
let didAddMethod = class_addMethod(self, selector.original, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))
if didAddMethod {
class_replaceMethod(self, selector.swizzled, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod))
} else {
method_exchangeImplementations(originalMethod, swizzledMethod);
}
}
}
}
// MARK: - Method Swizzling
public func custome_application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool {
print("is here")
return true
}
func custom_applicationDidEnterBackground(application: UIApplication) {
print("is herer")
}
}