SwiftLoadHook 中文介绍
This lib uses a hack way to achieve similar functions as Load()
or initialize()
.
Upon migrating a project to Swift 3.1, Xcode raises a warning:
Method ‘initialize()’ defines Objective-C class method ‘initialize’, which is not guaranteed to be invoked by Swift and will be disallowed in future versions.
- iOS 8.0
- swift 3.0
First, drop files under Sources
folder to your project.
Then, your target class should conforms to SelfAware
protocol, and implements the functions in SelfAware
protocol.
Finally, write the code you want in awake
function just like that in Load()
or Initialize()
.
This example is used to help you understand how to use, you can find the code in the files under Example
folder. In this example, I want to swizzle the IMP of function viewWillAppear()
in UIViewController
.
First, UIViewController
should conform to SelfAware
protocol and implement functions of the protocol.
extension UIViewController: SelfAware {
static func awake() {
UIViewController.classInit()
}
static func classInit() {
swizzleMethod
}
}
Then, I should implement swizzleMethod
function. while swizzling methods, we should use dispatch_once
in Load()
or Initialize()
function. However, since swift 3.x, we cannot find dispatch_once
in API. How can we handle this? We can use static let instance
to handle with it.
@objc func swizzled_viewWillAppear(_ animated: Bool) {
swizzled_viewWillAppear(animated)
print("swizzled_viewWillAppear")
}
private static let swizzleMethod: Void = {
let originalSelector = #selector(viewWillAppear(_:))
let swizzledSelector = #selector(swizzled_viewWillAppear(_:))
swizzlingForClass(UIViewController.self, originalSelector: originalSelector, swizzledSelector: swizzledSelector)
}()
private static func swizzlingForClass(_ forClass: AnyClass, originalSelector: Selector, swizzledSelector: Selector) {
let originalMethod = class_getInstanceMethod(forClass, originalSelector)
let swizzledMethod = class_getInstanceMethod(forClass, swizzledSelector)
guard (originalMethod != nil && swizzledMethod != nil) else {
return
}
if class_addMethod(forClass, originalSelector, method_getImplementation(swizzledMethod!), method_getTypeEncoding(swizzledMethod!)) {
class_replaceMethod(forClass, swizzledSelector, method_getImplementation(originalMethod!), method_getTypeEncoding(originalMethod!))
} else {
method_exchangeImplementations(originalMethod!, swizzledMethod!)
}
}
@JORDAN SMITH
Handling the Deprecation of initialize()
SwiftLoadHook is released under the MIT license. See LICENSE for details.