Swift中实现Observable机制

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原文地址: http://blog.csdn.net/cocos2der/article/details/51917539

今天给别人讲个Observable的实现和使用场景，结合Observable-Swift github: https://github.com/slazyk/Observable-Swift 讲了半天貌似还没有特别明白，故写了个简易的实现，讲述了下Observable属性监控机制。

//: Playground - noun: a place where people can play

import UIKit
import Foundation

// MARK: - Observable
class Observable<T> {
// 定义block结构
typealias Observer = T -> Void

// 申明一个block，用于数据改变的执行
private var observer: Observer?

// 数据发生变更，则通过observer告知
var value: T {
didSet {
observer?(value)
}
}

init(_ v: T) {
value = v
}

func observe(observer: Observer?) {
self.observer = observer
observer?(value)
}
}

// MARK: - People
struct PeopleModel {
let firstName: Observable<String>
let lastName: Observable<String>

init(firstName: String, lastName: String) {
self.firstName = Observable(firstName)
self.lastName = Observable(lastName)
}
}

// MARK: - Test

// test1
let people = PeopleModel(firstName: "sunny", lastName: "liu")
people.firstName.observe {
newValue in
print("firstName changed: \(newValue)")
}
people.lastName.observe {
print("lastName changed: \($0)")
}
people.firstName.value = "sunny2"
people.lastName.value = "liu2"

// test2
class House {
let lableHouseName =  UILabel()

init() {

}

var people: PeopleModel? {
didSet {
people?.firstName.observe{
[unowned self] in
self.lableHouseName.text = $0
}
}
}
}

这样貌似容易理解了，O(∩_∩)O哈哈~