本文是示例主要来自于官方的实例代码，可从这里下载 ，实例代码稍有改动。其中的图片来自于reactivex.io/

本文主要的作用是查看实例代码并查看对应实例代码的效果，不需要运行项目

操作符目录

• RxSwift官方使用示例之<创建和订阅Observables>
  • never、empty、just、of、from、create、range、repeatElement、generate、deferred、error、doOn
• RxSwift官方使用示例之<使用Subjects>
  • PublishSubject、ReplaySubject、BehaviorSubject
• RxSwift官方使用示例之<组合操作符>
  • startWith、merge、zip、combineLatest、Array.combineLatest、switchLatest、withLatestFrom
• RxSwift官方使用示例之<转换操作符>
  • map、flatMap 和 flatMapLatest、scan
• RxSwift官方使用示例之<过滤及条件操作符>
  • filter、distinctUntilChanged、elementAt、single、take、takeLast、takeWhile、takeUntil、skip、skipWhile、skipWhileWithIndex、skipUntil
• RxSwift官方使用示例之<数学和聚合操作符>
  • toArray、reduce、concat
• RxSwift官方使用示例之<可连接操作符>
  • interval、publish、replay、multicast
• RxSwift官方使用示例之<错误处理操作符>
  • catchAndReturn、catchError、retry、retry(_:)

debug 操作符会打印所有的 subscriptions, events, disposals

公用代码，之后的代码中会用到

enum TestError: Error {
    case test
}

catchAndReturn

通过发送一个元素并立即终止，来从发出错误的 Observable 序列中恢复

let disposeBag = DisposeBag()

let sequenceThatFails = PublishSubject<String>()

sequenceThatFails
    .catchAndReturn("😊")
    .subscribe { print($0) }
    .disposed(by: disposeBag)

sequenceThatFails.onNext("😬")
sequenceThatFails.onNext("😨")
sequenceThatFails.onNext("😡")
sequenceThatFails.onNext("🔴")
sequenceThatFails.onError(TestError.test)
print("over")

打印

next(😬)
next(😨)
next(😡)
next(🔴)
next(😊)
completed
over

catchError

通过转换到提供的可恢复的 Observable 序列来恢复发出错误的 Observable

let disposeBag = DisposeBag()

let sequenceThatFails = PublishSubject<String>()
let recoverySequence = PublishSubject<String>()

sequenceThatFails
    .catch {
        print("Error:", $0)
        return recoverySequence
    }
    .subscribe { print($0) }
    .disposed(by: disposeBag)

sequenceThatFails.onNext("😬")
sequenceThatFails.onNext("😨")
sequenceThatFails.onNext("😡")
sequenceThatFails.onNext("🔴")
sequenceThatFails.onError(TestError.test)

recoverySequence.onNext("😊")

打印

next(😬)
next(😨)
next(😡)
next(🔴)
Error: test
next(😊)

retry

当发生错误时，尝试重新订阅该 Observalbe 序列来恢复

let disposeBag = DisposeBag()
var count = 1

let sequenceThatErrors = Observable<String>.create { observer in
    observer.onNext("🍎")
    observer.onNext("🍐")
    observer.onNext("🍊")
    
    if count == 1 {
        observer.onError(TestError.test)
        print("Error encountered")
        count += 1
    }
    
    observer.onNext("🐶")
    observer.onNext("🐱")
    observer.onNext("🐭")
    observer.onCompleted()
    
    return Disposables.create()
}

sequenceThatErrors
    .retry()
    .subscribe(onNext: { print($0) })
    .disposed(by: disposeBag)

打印

🍎
🍐
🍊
Error encountered
🍎
🍐
🍊
🐶
🐱
🐭

retry(_:)

当发生错误时，尝试重新订阅该 Observalbe 序列来恢复，此时最多尝试指定次数

let disposeBag = DisposeBag()
var count = 1

let sequenceThatErrors = Observable<String>.create { observer in
    observer.onNext("🍎")
    observer.onNext("🍐")
    observer.onNext("🍊")
    
    if count < 5 {
        observer.onError(TestError.test)
        print("Error encountered")
        count += 1
    }
    
    observer.onNext("🐶")
    observer.onNext("🐱")
    observer.onNext("🐭")
    observer.onCompleted()
    
    return Disposables.create()
}

sequenceThatErrors
    .retry(3)
    .subscribe(onNext: { print($0) })
    .disposed(by: disposeBag)

打印

🍎
🍐
🍊
Error encountered
🍎
🍐
🍊
Error encountered
🍎
🍐
🍊
Error encountered
Unhandled error happened: test