RxSwift-中介者模式

强引用问题 OC版

1、方法一 didMoveToParentViewController

    override func viewDidLoad() {
        super.viewDidLoad()
        self.timerDyz = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerFire), userInfo: nil, repeats: true)
    }

    override func didMove(toParent parent: UIViewController?) {
        super.didMove(toParent: parent)
        if parent == nil {
            self.timerDyz?.invalidate()
            self.timerDyz = nil
        }
    }
    
    @objc func timerFire(){
        print("timer fire")
    }
    
    deinit {
        print("\(self) 走了")
    }

2、方法二 block

    override func viewDidLoad() {
        super.viewDidLoad()
        self.timerDyz = Timer.scheduledTimer(withTimeInterval: 1, repeats: true, block: { (timer) in
            print("timer fire dyz")
        })
    }

    deinit {
        self.timerDyz?.invalidate()
        self.timerDyz = nil
        print("\(self) 走了")
    }

3、方法三 引入中间变量

class ViewController: UIViewController {
    
    var timerDyz: Timer?    
    let target = NSObject()

    override func viewDidLoad() {
        super.viewDidLoad()

        class_addMethod(self.target.classForCoder, NSSelectorFromString("timerFiredyz"), method(for: NSSelectorFromString("timerFire")), "v@:")
        timerDyz = Timer.init(timeInterval: 1, target: self.target, selector: NSSelectorFromString("timerFiredyz"), userInfo: nil, repeats: true)
        RunLoop.current.add(timerDyz!, forMode: .common)

//        let sel = NSSelectorFromString("timerFire")
//        let method = class_getInstanceMethod(self.classForCoder, sel)
//        class_addMethod(self.target.classForCoder, sel, method_getImplementation(method!), "v@:")
//        timerDyz = Timer.init(timeInterval: 1, target: self.target, selector: NSSelectorFromString("timerFire"), userInfo: nil, repeats: true)
//        RunLoop.current.add(timerDyz!, forMode: .common)

    }

    @objc func timerFire(){
        print("timer fire")
    }
    
    deinit {
        self.timerDyz?.invalidate()
        self.timerDyz = nil
        print("\(self) 走了")
    }

}

3、方法三 引入中间层

class ViewController: UIViewController {
    let proxy: LGProxy = LGProxy()
    override func viewDidLoad() {
        super.viewDidLoad()
        let selector = NSSelectorFromString("timerFire")
        proxy.lg_scheduledTimer(timeInterval: 1, target: self, selector: selector, userInfo: nil, repeats: true)
    }
    
    @objc func timerFire(){
        print("timer fire")
    }
    
    deinit {
        print("\(self) 走了")
    }
}

class LGProxy: NSObject {
    
    weak var target: NSObjectProtocol?
    var sel: Selector?
    var lgTimer: Timer? = nil
    
    override init() {
        super.init()
    }
    
    func lg_scheduledTimer(timeInterval ti: TimeInterval, target aTarget: Any, selector aSelector: Selector, userInfo: Any?, repeats yesOrNo: Bool){
        self.lgTimer = Timer.init(timeInterval: ti, target: self, selector: aSelector, userInfo: userInfo, repeats: yesOrNo)
        RunLoop.current.add(self.lgTimer!, forMode: .common)
        
        self.target = aTarget as? NSObjectProtocol
        self.sel    = aSelector
        
        guard self.target?.responds(to: self.sel) == true else{
            return
        }
        
        let method = class_getInstanceMethod(self.classForCoder, #selector(lgTimerFire))
        class_replaceMethod(self.classForCoder, self.sel!, method_getImplementation(method!), method_getTypeEncoding(method!))
    }
    
    
    @objc fileprivate func lgTimerFire(){
        if self.target != nil{
            self.target!.perform(self.sel)
        }
        else{
            self.lgTimer?.invalidate()
            self.lgTimer = nil
        }
    }
  
    override func forwardingTarget(for aSelector: Selector!) -> Any? {
        if self.target?.responds(to: self.sel) == true {
            return self.target
        }
        else{
            print("心里没有点数,写这样的代码,还要我给你填坑")
            return super.forwardingTarget(for: aSelector)
        }        
    }
    
    deinit {
        print("\(self) 走了")
    }
    
}