# 4. RxSwift 核心

这一章主要介绍 **RxSwift** 的核心内容：

![](https://4217506537-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MWj545abP2yK86-qksJ%2Fsync%2F4b3276ae4b47b4d4337d24cfc90cfd1fcf8eb534.png?generation=1616819396601646\&alt=media)

* [Observable](https://3440217568.gitbook.io/rxswift/rxswift_core/observable) - 产生事件
* [Observer](https://3440217568.gitbook.io/rxswift/rxswift_core/observer) - 响应事件
* [Operator](https://3440217568.gitbook.io/rxswift/rxswift_core/operator) - 创建变化组合事件
* [Disposable](https://3440217568.gitbook.io/rxswift/rxswift_core/disposable) - 管理绑定（订阅）的生命周期
* [Schedulers](https://3440217568.gitbook.io/rxswift/rxswift_core/schedulers) - 线程队列调配

```swift
// Observable<String>
let text = usernameOutlet.rx.text.orEmpty.asObservable()

// Observable<Bool>
let passwordValid = text
    // Operator
    .map { $0.characters.count >= minimalUsernameLength }

// Observer<Bool>
let observer = passwordValidOutlet.rx.isHidden

// Disposable
let disposable = passwordValid
    // Scheduler 用于控制任务在那个线程队列运行
    .subscribeOn(MainScheduler.instance)
    .observeOn(MainScheduler.instance)
    .bind(to: observer)


...

// 取消绑定，你可以在退出页面时取消绑定
disposable.dispose()
```

下面几节会详细介绍这几个组件的功能和用法。

*ℹ️ 提示：这一章主要介绍一些偏理论方面的知识。你如果觉得阅读起来比较乏味的话，可以先**快速地浏览一遍**，了解 **RxSwift** 的核心组件大概有哪些内容。待以后遇到实际问题时，在回来查询。你可以直接跳到* [*更多例子*](https://3440217568.gitbook.io/rxswift/more_demo) *章节，去了解如何应用 **RxSwift**。*


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