RxSwift实践

以代码实践为主，在主要地方作了注释，方便日后查看和使用

• 声明DisposeBag的变量， 使用.disposed(by: bag)(旧版是.addDisposableTo(bag))，则RxSwift订阅对象会随控制器销毁

fileprivate lazy var bag: DisposeBag = DisposeBag()

RxSwift实现函数响应式编程，与观察者模式很类似

• Subject
  需要导入

import RxSwift

• PublishSubject、replayObject、BehaviorSubject、Variable

//MARK: PublishSubject 订阅者只能接收--->订阅之后发出的事件
            let publishSub = PublishSubject<String>()
            // 这个事件接收不到
            publishSub.onNext("18")
            publishSub.subscribe { (event: Event<String>) in
                
            }.disposed(by: bag)
            // 这个事件可以接收
            publishSub.onNext("111")
   
    //MARK: replayObject 订阅者可以接收订阅之前和订阅之后的事件
    //        .create(bufferSize: 2) --->指定buffer大小，决定接收事件个数
    //        .createUnbounded() ---> 无边界buffer，接收所有事件
            let replaySub = ReplaySubject<String>.createUnbounded()
            replaySub.onNext("a")
            replaySub.onNext("b")
            replaySub.onNext("c")
            
            replaySub.subscribe { (event: Event<String>) in
                
            }.disposed(by: bag)
            replaySub.onNext("d")

    //MARK: BehaviorSubject 订阅者可以接收i订阅之前最后一个事件
            let behavior = BehaviorSubject(value: "hehavior")
            behavior.onNext("a")
            behavior.onNext("b")
            //从这里开始接收
            behavior.onNext("c")
            
            behavior.subscribe { (event: Event<String>) in
                
            }.disposed(by: bag)
            behavior.onNext("f")
            behavior.onNext("g")
            
    //MARK:Variable
            /*
             *1.相当于behaviorSubject进行封箱
              2.如果想将variable当成obserable，让订阅者订阅，需要 as obserable 转成 obserable
             3.如果variable打算发出事件，直接修改对象value即可
             */
            let variable = BehaviorRelay(value: "a")
            variable.asObservable().subscribe { (event: Event<String>) in
                print(event)
            }.disposed(by: bag)

• 系统自带组件事件监听
  需要导入

import RxSwift
import RxCocoa

//MARK:1.按钮点击
        // 常规写法
       test1Btn.addTarget(self, action: #selector(btn1Click), for: .touchUpInside)
       test2Btn.addTarget(self, action: #selector(btn2Click), for: .touchUpInside)
        
        // Rx写法
        test1Btn.rx.tap.subscribe { (event: Event<()>) in
            print("按钮1发生点击111")
        }.disposed(by: bag)
        
        test2Btn.rx.tap.subscribe { (event: Event<()>) in
            print("按钮2发生点击222")
        }.disposed(by: bag)
//MARK:监听UITextField文字改变
        // 传统
       textField1.delegate = self
       textField2.delegate = self
        // Rx
        // 方式一：
        
        textField1.rx.text.subscribe { (event :Event<String?>) in
            
            print(event.element!!)
            
        }.disposed(by: bag)
        
        textField2.rx.text.subscribe { (event :Event<String?>) in
            
            print(event.element!!)
        }.disposed(by: bag)
        
        // 方式二：
        textField1.rx.text.subscribe(onNext: { (string :String?) in
          print(string!)

        }).disposed(by: bag)
        
        textField2.rx.text.subscribe(onNext: { (string :String?) in
          print(string!)

        }).disposed(by: bag)
        
//MARK:将textField内容显示到label
        textField1.rx.text.bind(to: lb1.rx.text).disposed(by: bag)
        textField2.rx.text.bind(to: lb2.rx.text).disposed(by: bag)
//MARK:KVO
        // 传统
        lb1.addObserver(self, forKeyPath: "text", options: .new, context: nil)
        // Rx
        lb1.rx.observe(String.self, "text").subscribe(onNext: { (string: String?) in
                print("observe")
            }).disposed(by: bag)

//MARK:监听ScrollView的滚动
        // 传统
        scrollView.contentSize = CGSize(width: 10000, height: 0)
        scrollView.delegate = self
        
        // Rx
        scrollView.rx.contentOffset.subscribe(onNext: {(point: CGPoint) in
            }).disposed(by: bag)
    }
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        print(change!)
    }

• 自定义事件never、just、create、range、repeat

 // never
    fileprivate func customRxObserable() {
        let neverO = Observable<String>.never()
        neverO.subscribe { (event: Event<String>) in
            print(event)
        }.disposed(by: bag)
        
        // 创建empty
        let empty = Observable<String>.empty()
        empty.subscribe { (event: Event<String>) in
            
        }.disposed(by: bag)
        
        // just
        let just = Observable.just("")
        just.subscribe { (event: Event<String>) in
            print(event)
        }.disposed(by: bag)
        
        // create
        let create = Observable.create{(obserber: AnyObserver<Any>) -> Disposable in
            obserber.onNext("111")
            obserber.onNext("12")
            obserber.onCompleted()
            return Disposables.create()
        }
        create.subscribe { (event: Event<Any>) in
            
        }.disposed(by: bag)
        
        let myJust = Observable.create { (observer: AnyObserver<String>) -> Disposable in
            observer.onNext("111")
            observer.onCompleted()
            return Disposables.create()
        }
        myJust.subscribe { (event: Event<String>) in
            print(event)
        }.disposed(by: bag)
    
    // range
        let range = Observable.range(start: 1, count: 10)
            range.subscribe { (event: Event<Int>) in
                print(event.element!)
            }.disposed(by: bag)
    
    // repeat
        let repeatO = Observable.repeatElement("hello world")
        repeatO.take(5).subscribe { (event: Event<String>) in
            print(event)
        }.disposed(by: bag)
        /*
         *.subscribe { (event: Event<String>) in
             print(event)
         }.disposed(by: bag)
         */