ObjCRuntimeTools is a Swift library that provides powerful tools for working with Objective-C runtime features, including property association and method swizzling. It leverages modern Swift macros to simplify and enhance the use of these runtime capabilities.
- Property Association: easily associate properties with Objective-C objects using the
@Associatedmacro. - Swizzling: perform type-safe and boilerplate-free runtime swizzling with the
#swizzlemacro.
Add ObjCRuntimeTools to your Swift Package Manager dependencies:
.package(url: "https://github.com/davdroman/objc-runtime-tools", from: "0.1.0"),Then, add the dependency to your desired target:
.product(name: "ObjCRuntimeTools", package: "objc-runtime-tools"),Use the @Associated macro to associate properties with Objective-C objects:
class MyClass: NSObject {}
extension MyClass {
@Associated(.retain(.nonatomic))
var associatedProperty: String = "Default Value"
}Use the #swizzle macro to perform function, getter, or setter swizzling.
try #swizzle(UIViewController.viewDidLoad) { $self in
print("Before")
self.viewDidLoad()
print("After")
}
try #swizzle(UIViewController.viewDidAppear, param: Bool.self) { $self, animated in
print("Before")
self.viewDidAppear(animated)
print("After")
}
try #swizzle(UITextField.resignFirstResponder, returning: Bool.self) { $self in
print("Before")
let result = self.resignFirstResponder()
print("After")
return result
}
try #swizzle(
UIScrollView.touchesShouldBegin,
params: Set<UITouch>.self, UIEvent?.self, UIView.self,
returning: Bool.self
) { $self, touches, event, view in
print("Before")
let result = self.touchesShouldBegin(touches, with: event, in: view)
print("After")
return result
}try #swizzle(getter: \UIView.isHidden, returning: Bool.self) { $self in
print("Before")
let isHidden = self.isHidden
print("After")
return isHidden
}try #swizzle(setter: \UIView.isHidden, param: Bool.self) { $self, isHidden in
print("Before")
self.isHidden = isHidden
print("After")
}This library is inspired by and builds upon the following projects: