联合 Observable - Combining Operator
startWith
startWith 操作符会在 Observable 头部插入一些元素。（如果你想在尾部加入一些元素可以用concat）
eg:
func startWith() {
Observable.of("🐶", "🐱", "🐭", "🐹")
.startWith("First")
.startWith("Second")
.startWith("Third")
.startWith("1", "2", "3")
.debug("startWith")
.subscribe()
.disposed(by: disposeBag)
}
输出如下：
2017-12-27 12:42:41.259: startWith -> subscribed
2017-12-27 12:42:41.259: startWith -> Event next(1)
2017-12-27 12:42:41.259: startWith -> Event next(2)
2017-12-27 12:42:41.259: startWith -> Event next(3)
2017-12-27 12:42:41.259: startWith -> Event next(Third)
2017-12-27 12:42:41.259: startWith -> Event next(Second)
2017-12-27 12:42:41.259: startWith -> Event next(First)
2017-12-27 12:42:41.259: startWith -> Event next(🐶)
2017-12-27 12:42:41.259: startWith -> Event next(🐱)
2017-12-27 12:42:41.259: startWith -> Event next(🐭)
2017-12-27 12:42:41.259: startWith -> Event next(🐹)
2017-12-27 12:42:41.260: startWith -> Event completed
2017-12-27 12:42:41.260: startWith -> isDisposed
combineLatest
combineLatest 操作符将多个 Observables 中最新的元素通过一个函数组合起来，然后将这个组合的结果发出来。
这些源 Observables 中任何一个发出一个元素，他都会发出一个元素（前提是，这些 Observables 曾经发出过元素）。
eg:
func combineLatest() {
Observable<String>
.combineLatest(getFirstObservable(), getSecondObservable(), resultSelector: { (fstr, sstr) -> String in
return fstr + " | " + sstr
})
.debug("combineLatest")
.subscribe()
.disposed(by: disposeBag)
}
输出如下
2017-12-27 12:45:26.780: combineLatest -> subscribed
2017-12-27 12:45:27.782: combineLatest -> Event next(First -> 1|A | Second -> 1)
2017-12-27 12:45:27.782: combineLatest -> Event next(First -> 1|B | Second -> 1)
2017-12-27 12:45:27.782: combineLatest -> Event next(First -> 1|C | Second -> 1)
2017-12-27 12:45:30.886: combineLatest -> Event next(First -> 1|C | Second -> 2)
2017-12-27 12:45:31.781: combineLatest -> Event next(First -> 2|A | Second -> 2)
2017-12-27 12:45:31.782: combineLatest -> Event next(First -> 2|B | Second -> 2)
2017-12-27 12:45:31.782: combineLatest -> Event next(First -> 2|C | Second -> 2)
2017-12-27 12:45:34.886: combineLatest -> Event next(First -> 2|C | Second -> 3)
2017-12-27 12:45:35.781: combineLatest -> Event next(First -> 3|A | Second -> 3)
2017-12-27 12:45:35.781: combineLatest -> Event next(First -> 3|B | Second -> 3)
2017-12-27 12:45:35.781: combineLatest -> Event next(First -> 3|C | Second -> 3)
2017-12-27 12:45:35.781: combineLatest -> Event completed
2017-12-27 12:45:35.782: combineLatest -> isDisposed
zip
通过一个函数将多个 Observables 的元素组合起来，然后将每一个组合的结果发出来。
zip 操作符将多个(最多不超过8个) Observables 的元素通过一个函数组合起来，然后将这个组合的结果发出来。它会严格的按照序列的索引数进行组合。
例如，返回的 Observable 的第一个元素，是由每一个源 Observables 的第一个元素组合出来的。它的第二个元素 ，是由每一个源 Observables 的第二个元素组合出来的。它的第三个元素 ，是由每一个源 Observables 的第三个元素组合出来的，以此类推。
它的元素数量等于源 Observables 中元素数量最少的那个。
eg:
func zip() {
let disposeBag = DisposeBag()
let first = PublishSubject<String>()
let second = PublishSubject<String>()
Observable
.zip(first, second) { $0 + $1 }
.subscribe(onNext: { print($0) })
.disposed(by: disposeBag)
first.onNext("1")
second.onNext("A")
first.onNext("2")
second.onNext("B")
second.onNext("C")
second.onNext("D")
first.onNext("3")
first.onNext("4")
first.onNext("5")
}
输出如下：
1A
2B
3C
4D
withLatestFrom
将两 Observables 最新的元素通过一个函数组合以来，当第一个 Observable 发出一个元素，就将组合后的元素发送出来
withLatestFrom 操作符将两个 Observables 中最新的元素通过一个函数组合起来，然后将这个组合的结果发出来。
当第一个 Observable 发出一个元素时，就立即取出第二个 Observable 中最新的元素，通过一个组合函数将两个最新的元素合并后发送出去。
eg:
func withLatestFrom() {
// 当第一个 Observable 发出一个元素时，就立即取出第二个 Observable 中最新的元素，
// 然后把第二个 Observable 中最新的元素发送出去。
print("============================First============================")
getFirstObservable()
.withLatestFrom(getSecondObservable())
.debug("withLatestFrom")
.subscribe()
.disposed(by: disposeBag)
// 当第一个 Observable 发出一个元素时，就立即取出第二个 Observable 中最新的元素，
// 然后把第一个 Observable 中最新的元素first和然后把第二个 Observable 中最新的元素second组合first+second发送出去。
delayTime(10) {
print("============================Second============================")
self.getFirstObservable()
.withLatestFrom(self.getSecondObservable(), resultSelector: { (first, second) -> String in
return first + " <====> " + second
})
.debug("withLatestFrom & Function")
.subscribe()
.disposed(by: self.disposeBag)
}
}
输出如下：
============================First============================
2017-12-27 12:50:16.250: withLatestFrom -> subscribed
2017-12-27 12:50:17.253: withLatestFrom -> Event next(Second -> 1)
2017-12-27 12:50:17.253: withLatestFrom -> Event next(Second -> 1)
2017-12-27 12:50:17.253: withLatestFrom -> Event next(Second -> 1)
2017-12-27 12:50:21.750: withLatestFrom -> Event next(Second -> 2)
2017-12-27 12:50:21.750: withLatestFrom -> Event next(Second -> 2)
2017-12-27 12:50:21.750: withLatestFrom -> Event next(Second -> 2)
2017-12-27 12:50:26.144: withLatestFrom -> Event next(Second -> 3)
2017-12-27 12:50:26.144: withLatestFrom -> Event next(Second -> 3)
2017-12-27 12:50:26.144: withLatestFrom -> Event next(Second -> 3)
2017-12-27 12:50:26.145: withLatestFrom -> Event completed
2017-12-27 12:50:26.145: withLatestFrom -> isDisposed
============================Second============================
2017-12-27 12:50:26.253: withLatestFrom & Function -> subscribed
2017-12-27 12:50:27.254: withLatestFrom & Function -> Event next(First -> 1|A <====> Second -> 1)
2017-12-27 12:50:27.255: withLatestFrom & Function -> Event next(First -> 1|B <====> Second -> 1)
2017-12-27 12:50:27.255: withLatestFrom & Function -> Event next(First -> 1|C <====> Second -> 1)
2017-12-27 12:50:31.254: withLatestFrom & Function -> Event next(First -> 2|A <====> Second -> 2)
2017-12-27 12:50:31.254: withLatestFrom & Function -> Event next(First -> 2|B <====> Second -> 2)
2017-12-27 12:50:31.254: withLatestFrom & Function -> Event next(First -> 2|C <====> Second -> 2)
2017-12-27 12:50:35.253: withLatestFrom & Function -> Event next(First -> 3|A <====> Second -> 3)
2017-12-27 12:50:35.253: withLatestFrom & Function -> Event next(First -> 3|B <====> Second -> 3)
2017-12-27 12:50:35.253: withLatestFrom & Function -> Event next(First -> 3|C <====> Second -> 3)
2017-12-27 12:50:35.254: withLatestFrom & Function -> Event completed
2017-12-27 12:50:35.254: withLatestFrom & Function -> isDisposed
merge
通过使用 merge 操作符你可以将多个 Observables 合并成一个，当某一个 Observable 发出一个元素时，他就将这个元素发出。
如果，某一个 Observable 发出一个 onError 事件，那么被合并的 Observable 也会将它发出，并且立即终止序列。
eg:
func merge() {
let subject1 = PublishSubject<String>()
let subject2 = PublishSubject<String>()
Observable.of(subject1, subject2)
.merge()
.subscribe(onNext: { print($0) })
.disposed(by: disposeBag)
subject1.onNext("🅰️")
subject1.onNext("🅱️")
subject2.onNext("1️⃣")
subject2.onNext("2️⃣")
subject1.onNext("🆎")
subject2.onNext("3️⃣")
let err = TError.init(errorCode: 0, errorString: "Test Error", errorData: nil)
subject1.onError(err)
subject2.onNext("4️⃣")
subject2.onNext("5️⃣")
}
输出如下：
2017-12-27 12:56:10.984: merge -> subscribed
2017-12-27 12:56:10.986: merge -> Event next(🅰️)
2017-12-27 12:56:10.986: merge -> Event next(🅱️)
2017-12-27 12:56:10.987: merge -> Event next(1️⃣)
2017-12-27 12:56:10.987: merge -> Event next(2️⃣)
2017-12-27 12:56:10.987: merge -> Event next(🆎)
2017-12-27 12:56:10.987: merge -> Event next(3️⃣)
2017-12-27 12:56:10.988: merge -> Event error(TError(errorCode: 0, errorString: "Test Error", errorData: nil))
Unhandled error happened: TError(errorCode: 0, errorString: "Test Error", errorData: nil)
subscription called from:
0 RxSwift 0x0000000109fa158c _T07RxSwift14ObservableTypePAAE9subscribeAA10Disposable_py1EQzcSg6onNext_ys5Error_pcSg0gI0yycSg0G9CompletedAM0G8DisposedtF + 780
1 RxSwiftExample 0x0000000109853023 _T011RxSwiftExample8OperatorC5mergeyyF + 1427
2 RxSwiftExample 0x0000000109853884 _T011RxSwiftExample8OperatorC5mergeyyFTo + 36
3 RxSwiftExample 0x0000000109877de1 _T011RxSwiftExample27OperatorTableViewControllerC11viewDidLoadyyFy10Foundation9IndexPathVcfU1_ + 897
4 RxSwiftExample 0x0000000109877f17 _T011RxSwiftExample27OperatorTableViewControllerC11viewDidLoadyyFy10Foundation9IndexPathVcfU1_TA + 103
5 RxSwiftExample 0x0000000109838da0 _T010Foundation9IndexPathVIxx_ACIxi_TR + 48
6 RxSwiftExample 0x0000000109877fa2 _T010Foundation9IndexPathVIxx_ACIxi_TRTA + 66
7 RxSwift 0x0000000109fa1d35 _T07RxSwift14ObservableTypePAAE9subscribeAA10Disposable_py1EQzcSg6onNext_ys5Error_pcSg0gI0yycSg0G9CompletedAM0G8DisposedtFyAA5EventOyAGGcfU_ + 885
8 RxSwift 0x0000000109fa228a _T07RxSwift14ObservableTypePAAE9subscribeAA10Disposable_py1EQzcSg6onNext_ys5Error_pcSg0gI0yycSg0G9CompletedAM0G8DisposedtFyAA5EventOyAGGcfU_TA + 282
9 RxSwift 0x0000000109ed7998 _T07RxSwift17AnonymousObserverC6onCoreyAA5EventOyxGF + 408
10 RxSwift 0x0000000109fa9026 _T07RxSwift12ObserverBaseC2onyAA5EventOyxGF + 742
11 RxSwift 0x0000000109fa95be _T07RxSwift12ObserverBaseCyxGAA0C4TypeAAlAaEP2onyAA5EventOy1EQzGFTW + 62
12 RxSwift 0x0000000109ed8c93 _T0TA + 115
13 RxSwift 0x0000000109ee33a7 _T07RxSwift5EventOyxGIxi_ADytIxir_1EQyd__RszAA12ObserverTypeRd__r__lTR + 23
14 RxSwift 0x0000000109ff5bc6 _T07RxSwift5EventOyxGIxi_ADytIxir_1EQyd__RszAA12ObserverTypeRd__r__lTRTA.47 + 118
15 RxSwift 0x0000000109ee3770 _T07RxSwift5EventOyxGytIxir_ADIxi_lTR + 16
16 RxSwift 0x0000000109ee5332 _T07RxSwift5EventOyxGytIxir_ADIxi_lTRTA.18 + 82
17 RxSwift 0x0000000109ee4564 _T07RxSwift8dispatchyAA3BagVyyAA5EventOyxGcG_AGtlF + 900
18 RxSwift 0x0000000109fef92e _T07RxSwift36ShareReplay1WhileConnectedConnection33_E9FE621655D67A613BF2FC2D9B3041FCLLC2onyAA5EventOyxGF + 1230
19 RxSwift 0x0000000109ff1aeb _T07RxSwift36ShareReplay1WhileConnectedConnection33_E9FE621655D67A613BF2FC2D9B3041FCLLCyxGAA12ObserverTypeAAlAaFP2onyAA5EventOy1EQzGFTW + 43
20 RxSwift 0x0000000109ffdbcc _T07RxSwift4SinkC9forwardOnyAA5EventOy1EQzGF + 780
21 RxSwift 0x0000000109ef5ff7 _T07RxSwift9CatchSink33_7E15DB08AB19A7B882D5C92A393C6F6DLLC2onyAA5EventOy1EQzGF + 823
22 RxSwift 0x0000000109ef6a5b _T07RxSwift9CatchSink33_7E15DB08AB19A7B882D5C92A393C6F6DLLCyxGAA12ObserverTypeA2aFRzlAaFP2onyAA5EventOy1EQzGFTW + 43
23 RxSwift 0x0000000109fa6f11 _T07RxSwift32ObserveOnSerialDispatchQueueSink33_277A93ABA8477198C125F3F26B2D4B62LLCADyxGAA0efG9SchedulerC9scheduler_x8observerAA10Cancelable_p6canceltcfcAA10Disposable_pAE4sink_AA5EventOy1EQzG5eventtcfU_ + 833
24 RxSwift 0x0000000109fa8579 _T07RxSwift32ObserveOnSerialDispatchQueueSink33_277A93ABA8477198C125F3F26B2D4B62LLCADyxGAA0efG9SchedulerC9scheduler_x8observerAA10Cancelable_p6canceltcfcAA10Disposable_pAE4sink_AA5EventOy1EQzG5eventtcfU_TA + 9
25 RxSwift 0x0000000109fa77d9 _T07RxSwift32ObserveOnSerialDispatchQueueSink33_277A93ABA8477198C125F3F26B2D4B62LLCyxGAA5EventOy1EQzGAA10Disposable_pIxxir_AE_AJtAaK_pIxir_AA12ObserverTypeRzlTR + 137
26 RxSwift 0x0000000109fa8786 _T07RxSwift32ObserveOnSerialDispatchQueueSink33_277A93ABA8477198C125F3F26B2D4B62LLCyxGAA5EventOy1EQzGAA10Disposable_pIxxir_AE_AJtAaK_pIxir_AA12ObserverTypeRzlTRTA + 102
27 RxSwift 0x0000000109f80564 _T07RxSwift13MainSchedulerC16scheduleInternalAA10Disposable_px_AaE_pxc6actiontlF + 484
28 RxSwift 0x0000000109feca4d _T07RxSwift28SerialDispatchQueueSchedulerC8scheduleAA10Disposable_px_AaE_pxc6actiontlF + 173
29 RxSwift 0x0000000109fa76cc _T07RxSwift32ObserveOnSerialDispatchQueueSink33_277A93ABA8477198C125F3F26B2D4B62LLC6onCoreyAA5EventOy1EQzGF + 1148
30 RxSwift 0x0000000109fa9026 _T07RxSwift12ObserverBaseC2onyAA5EventOyxGF + 742
31 RxSwift 0x0000000109fa95be _T07RxSwift12ObserverBaseCyxGAA0C4TypeAAlAaEP2onyAA5EventOy1EQzGFTW + 62
32 RxSwift 0x0000000109ffdbcc _T07RxSwift4SinkC9forwardOnyAA5EventOy1EQzGF + 780
33 RxSwift 0x000000010a0080e0 _T07RxSwift15SubscribeOnSink33_B44C3DD7F62EF81799E6347E59A266A2LLC2onyAA5EventOy1EQzGF + 400
34 RxSwift 0x000000010a008e0b _T07RxSwift15SubscribeOnSink33_B44C3DD7F62EF81799E6347E59A266A2LLCyxq_GAA12ObserverTypeA2A010ObservableP0RzAaFR_1EQy_AHRtzr0_lAaFP2onyAA5EventOyAHQzGFTW + 43
35 RxSwift 0x0000000109ffdbcc _T07RxSwift4SinkC9forwardOnyAA5EventOy1EQzGF + 780
36 RxSwift 0x0000000109f81695 _T07RxSwift7MapSink33_5428EFA9A9B0C0340021B871D2E5AC01LLC2onyAA5EventOyxGF + 1093
37 RxSwift 0x0000000109f81beb _T07RxSwift7MapSink33_5428EFA9A9B0C0340021B871D2E5AC01LLCyxq_GAA12ObserverTypeA2aFR_r0_lAaFP2onyAA5EventOy1EQzGFTW + 43
38 RxSwift 0x0000000109ffdbcc _T07RxSwift4SinkC9forwardOnyAA5EventOy1EQzGF + 780
39 RxSwift 0x000000010a0080e0 _T07RxSwift15SubscribeOnSink33_B44C3DD7F62EF81799E6347E59A266A2LLC2onyAA5EventOy1EQzGF + 400
40 RxSwift 0x000000010a008e0b _T07RxSwift15SubscribeOnSink33_B44C3DD7F62EF81799E6347E59A266A2LLCyxq_GAA12ObserverTypeA2A010ObservableP0RzAaFR_1EQy_AHRtzr0_lAaFP2onyAA5EventOyAHQzGFTW + 43
41 RxSwift 0x0000000109ed8c93 _T0TA + 115
42 RxSwift 0x0000000109ee33a7 _T07RxSwift5EventOyxGIxi_ADytIxir_1EQyd__RszAA12ObserverTypeRd__r__lTR + 23
43 RxSwift 0x0000000109ff5a36 _T07RxSwift5EventOyxGIxi_ADytIxir_1EQyd__RszAA12ObserverTypeRd__r__lTRTA + 118
44 RxSwift 0x0000000109ee3770 _T07RxSwift5EventOyxGytIxir_ADIxi_lTR + 16
45 RxSwift 0x0000000109ee5332 _T07RxSwift5EventOyxGytIxir_ADIxi_lTRTA.18 + 82
46 RxSwift 0x0000000109ee4564 _T07RxSwift8dispatchyAA3BagVyyAA5EventOyxGcG_AGtlF + 900
47 RxSwift 0x0000000109ff2eee _T07RxSwift29ShareWhileConnectedConnection33_E9FE621655D67A613BF2FC2D9B3041FCLLC2onyAA5EventOyxGF + 1230
48 RxSwift 0x0000000109ff4abb _T07RxSwift29ShareWhileConnectedConnection33_E9FE621655D67A613BF2FC2D9B3041FCLLCyxGAA12ObserverTypeAAlAaFP2onyAA5EventOy1EQzGFTW + 43
49 RxSwift 0x0000000109ffdbcc _T07RxSwift4SinkC9forwardOnyAA5EventOy1EQzGF + 780
50 RxSwift 0x0000000109f66dfb _T07RxSwift6DoSink33_51F9E615740E91B2E920965FFBB1EED3LLC2onyAA5EventOy1EQzGF + 843
51 RxSwift 0x0000000109f674eb _T07RxSwift6DoSink33_51F9E615740E91B2E920965FFBB1EED3LLCyxGAA12ObserverTypeA2aFRzlAaFP2onyAA5EventOy1EQzGFTW + 43
52 RxSwift 0x0000000109ed8c93 _T0TA + 115
53 RxSwift 0x0000000109ee33a7 _T07RxSwift5EventOyxGIxi_ADytIxir_1EQyd__RszAA12ObserverTypeRd__r__lTR + 23
54 RxSwift 0x0000000109fbd396 _T07RxSwift5EventOyxGIxi_ADytIxir_1EQyd__RszAA12ObserverTypeRd__r__lTRTA + 118
55 RxSwift 0x0000000109ee3770 _T07RxSwift5EventOyxGytIxir_ADIxi_lTR + 16
56 RxSwift 0x0000000109ee5332 _T07RxSwift5EventOyxGytIxir_ADIxi_lTRTA.18 + 82
57 RxSwift 0x0000000109ee4564 _T07RxSwift8dispatchyAA3BagVyyAA5EventOyxGcG_AGtlF + 900
58 RxSwift 0x0000000109fbb1ca _T07RxSwift14PublishSubjectC2onyAA5EventOyxGF + 1018
59 RxCocoa 0x0000000109c6cd91 _T07RxSwift14PublishSubjectC2onyAA5EventOyxGFTA + 17
60 RxCocoa 0x0000000109c6c46d _T07RxSwift5EventOySayypGGIxi_AEIxx_TR + 29
61 RxCocoa 0x0000000109c6cd6e _T07RxSwift5EventOySayypGGIxi_AEIxx_TRTA + 78
62 RxCocoa 0x0000000109c6a5eb _T07RxCocoa13DelegateProxyC14_methodInvokedy10ObjectiveC8SelectorV_SayypG13withArgumentstF + 283
63 RxCocoa 0x0000000109c6a664 _T07RxCocoa13DelegateProxyC14_methodInvokedy10ObjectiveC8SelectorV_SayypG13withArgumentstFTo + 84
64 RxCocoa 0x0000000109c3b588 -[_RXDelegateProxy forwardInvocation:] + 536
65 CoreFoundation 0x000000010dee1cd8 ___forwarding___ + 760
66 CoreFoundation 0x000000010dee1958 _CF_forwarding_prep_0 + 120
67 UIKit 0x000000010b309839 -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] + 1810
68 UIKit 0x000000010b309a54 -[UITableView _userSelectRowAtPendingSelectionIndexPath:] + 344
69 UIKit 0x000000010b1d2d59 _runAfterCACommitDeferredBlocks + 318
70 UIKit 0x000000010b1c1bb1 _cleanUpAfterCAFlushAndRunDeferredBlocks + 280
71 UIKit 0x000000010b1f10e0 _afterCACommitHandler + 137
72 CoreFoundation 0x000000010df01c07 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
73 CoreFoundation 0x000000010df01b5e __CFRunLoopDoObservers + 430
74 CoreFoundation 0x000000010dee6124 __CFRunLoopRun + 1572
75 CoreFoundation 0x000000010dee5889 CFRunLoopRunSpecific + 409
76 GraphicsServices 0x00000001136149c6 GSEventRunModal + 62
77 UIKit 0x000000010b1c75d6 UIApplicationMain + 159
78 RxSwiftExample 0x0000000109858c07 main + 55
79 libdyld.dylib 0x000000010f7bcd81 start + 1
80 ??? 0x0000000000000001 0x0 + 1
2017-12-27 12:56:10.991: merge -> isDisposed
switchLatest
当你的事件序列是一个事件序列的序列 (Observable<Observable<T>>) 的时候，（可以理解成二维序列）
可以使用 switch 将序列的序列平铺成一维，并且在出现新的序列的时候，自动切换到最新的那个序列上。
和 merge 相似的是，它也是起到了将多个序列拍平成一条序列的作用。
⚠️注意：当源
Observable发出一个新的Observable时，而不是当新的Observable发出一个项目时，它将从之前发出的Observable中取消订阅。这意味着在后面的
Observable被发射的时间和随后的Observable本身开始发射的时间之间，前一个Observable发射的物体将被丢弃。
eg:
func switchLatest() {
// 第一个： 发送3个元素
let innerObservable_1 = Observable<String>.of("innerObservable_1: 1",
"innerObservable_1: 2",
"innerObservable_1: 3")
// 持续1秒发出一个元素，递增
let innerObservable_2 = Observable<Int>.interval(1, scheduler: MainScheduler.instance).map { (value) -> String in
print("innerObservable_2 => Send \(value)")
return "innerObservable_2: \(value)"
}
// 持续1秒发出一个元素，递增
let innerObservable_3 = Observable<Int>.interval(1, scheduler: MainScheduler.instance).map { (value) -> String in
print("innerObservable_3 => Send \(value)")
return "innerObservable_3: \(value)"
}
let externalObservable = Observable<Observable<String>>.create({ (observer) -> Disposable in
observer.onNext(innerObservable_1)
delayTime(2, block: {
observer.onNext(innerObservable_2)
})
delayTime(6, block: {
observer.onNext(innerObservable_3)
})
delayTime(12, block: {
// 不加 observer.onNext(Observable<String>.never()) 的话，innerObservable_3会持续不断的发送
print("observer.onNext(Observable<String>.never())")
print("observer.onCompleted()")
observer.onNext(Observable<String>.never())
observer.onCompleted()
})
return Disposables.create()
})
externalObservable
.switchLatest()
.debug("switchLatest")
.subscribe()
.disposed(by: disposeBag)
}
输出如下：
2017-12-27 12:59:48.877: switchLatest -> subscribed
2017-12-27 12:59:48.878: switchLatest -> Event next(innerObservable_1: 1)
2017-12-27 12:59:48.878: switchLatest -> Event next(innerObservable_1: 2)
2017-12-27 12:59:48.878: switchLatest -> Event next(innerObservable_1: 3)
innerObservable_2 => Send 0
2017-12-27 12:59:51.880: switchLatest -> Event next(innerObservable_2: 0)
innerObservable_2 => Send 1
2017-12-27 12:59:52.881: switchLatest -> Event next(innerObservable_2: 1)
innerObservable_2 => Send 2
2017-12-27 12:59:53.881: switchLatest -> Event next(innerObservable_2: 2)
innerObservable_3 => Send 0
2017-12-27 12:59:55.879: switchLatest -> Event next(innerObservable_3: 0)
innerObservable_3 => Send 1
2017-12-27 12:59:56.879: switchLatest -> Event next(innerObservable_3: 1)
innerObservable_3 => Send 2
2017-12-27 12:59:57.878: switchLatest -> Event next(innerObservable_3: 2)
innerObservable_3 => Send 3
2017-12-27 12:59:58.879: switchLatest -> Event next(innerObservable_3: 3)
innerObservable_3 => Send 4
2017-12-27 12:59:59.878: switchLatest -> Event next(innerObservable_3: 4)
observer.onNext(Observable<String>.never())
observer.onCompleted()