Question

好的，我在Swift中遇到了addObserver函数的问题。如果我改变对象B的反应值，那怎么可能呢？（没有A知道B但是B有一个变量，引用了A）

例如：

class A {
var willChange: Int = 0

// if something happened -> willChange = 1
}

class B {
  let someThing = A()

  //Something like this maybe but i don't really want to check, just get a notice
  if someThing.willChange != 0 {
  }

  func whatEver() {
  //called if willChange is changed
  ...
  }
}

不仅如果willChange改变了它必须被通知，只要我想要的任何事情发生在A - ＆gt;证明B. 思考观察者模式，但也许有人可以解释如果可能的话。

Answer 1

这样的事情：

class A {
   weak var observer : AnyObject?
   var willChange: Int = 0{
     didSet{
          if let bObject = observer as? B{
             bObject.whatEver()
          }
     }
   }
}

class B {
  let someThing = A()
  someThing.observer = self

  func whatEver() {
  //called if willChange is changed
  ...
  }
}

Observer，Action Listener，iOS Swift中的KVO

1 个答案: