前言
Runtime介绍
学习一个东西至少要先知道它是个啥，你一定听说过“运行时是 Objective-C 的一个特色”，这里的“运行时”就是指 runtime 了。
老的方式initialize现在已经不适用了，需要用新的方式代替。
思路: 定义一个启动的协议，在app完成启动的方法里把需要做method swizzle的类跑一边协议的方法
第一种
1、Step One
protocol SelfAware: class {
static func awake() }
class NothingToSeeHere {
static func harmlessFunction() {
let typeCount = Int(objc_getClassList(nil, 0)) let types = UnsafeMutablePointer<AnyClass?>.allocate(capacity: typeCount) let autoreleasingTypes = AutoreleasingUnsafeMutablePointer<AnyClass?>(types) objc_getClassList(autoreleasingTypes, Int32(typeCount)) for index in 0 ..< typeCount {
(types[index] as? SelfAware.Type)?.awake() }
types.deallocate(capacity: typeCount) }
}
2、step two
extension UIApplication {
private static let runOnce: Void = {
NothingToSeeHere.harmlessFunction() }
() override open var next: UIResponder? {
// Called before applicationDidFinishLaunching UIApplication.runOnce return super.next }
}
3、step three
遵循协议SelfAware,实现awake()
第二种(类似第一种)
1、创建一个swizzle注入的协议
public protocol SwizzlingInjection: class {
static func inject()}
2、创建swizzle helper
open class SwizzlingManager {
//只会调用一次的方法 private static let doOnce: Any? = {
UIViewController.inject() return nil }
() open static func enableInjection() {
_ = SwizzlingManager.doOnce }
}
3、给UIApplication 创建分类调用那个一次方法
extension UIApplication{
open override var next: UIResponder?{
SwizzlingManager.enableInjection() return super.next }
}
4、在你需要的类中遵循注入协议
extension UIViewController: SwizzlingInjection{
public static func inject() {
//确保不是子类 guard self === UIViewController.self else {
return }
DispatchQueue.once(token: "com.moglo.urmoji.UIViewController") {
//do swizzle method }
}
}
once只执行一次的方法
public extension DispatchQueue {
private static var _onceTracker = [String]() public class func once(file: String = #file, function: String = #function, line: Int = #line, block:()->Void) {
let token = file + ":" + function + ":" + String(line) once(token: token, block: block) }
/** Executes a block of code, associated with a unique token, only once. The code is thread safe and will only execute the code once even in the presence of multithreaded calls. - parameter token: A unique reverse DNS style name such as com.vectorform.<name> or a GUID - parameter block: Block to execute once */ public class func once(token: String, block:()->Void) {
objc_sync_enter(self) defer {
objc_sync_exit(self) }
if _onceTracker.contains(token) {
return }
_onceTracker.append(token) block() }
//delay typealias Task = (_ cancel : Bool) -> Void @discardableResult static func delay(time : TimeInterval, task: @escaping () -> ()) -> Task? {
func dispatch_later(block : @escaping () -> ()) {
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + time , execute: block) }
var closure : (() -> ())? = task var result : Task? let delayedClosure : Task = {
cancel in if let internalClosure = closure {
if cancel == false {
DispatchQueue.main.async(execute: internalClosure) }
}
closure = nil result = nil }
result = delayedClosure dispatch_later {
() -> () in if let delayedClosure = result {
delayedClosure(false) }
}
return result }
static func cancel(task : Task?) {
task?(true) }
}
总结
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对脚本之家的支持。
