Swift中的超级简单的尾随闭包语法

Question

我正在尝试遵循Swift文档中的示例来进行结尾的闭包。

这是功能：

func someFunctionThatTakesAClosure(closure: () -> Void) {
    // function body goes here
    print("we do something here and then go back")//does not print
}

我在这里称呼它。

        print("about to call function")//prints ok
        someFunctionThatTakesAClosure(closure: {
            print("we did what was in the function and can now do something else")//does not print
        })
        print("after calling function")//prints ok

但是，该函数没有被调用。 上面有什么问题？

这是Apple的示例：

func someFunctionThatTakesAClosure（closure：（）-> Void）{//函数体在这里}

//以下是不使用尾随闭包而调用此函数的方式：

someFunctionThatTakesAClosure（closure：{//封闭体在这里}）

Answer 1

文档对您所需的解释不是很清楚

print("1")
someFunctionThatTakesAClosure() {  // can be also  someFunctionThatTakesAClosure { without ()
    print("3") 

}

---

func someFunctionThatTakesAClosure(closure: () -> Void) { 
   print("2") 

   /// do you job here and line blow will get you back
    closure()
}  

尾随闭包用于完成操作，例如当您执行网络请求并最终返回响应时

func someFunctionThatTakesAClosure(completion:  @escaping ([String]) -> Void) { 
   print("inside the function body") 
   Api.getData { 
      completion(arr)
   }
}  

并致电

print("Before calling the function")
someFunctionThatTakesAClosure { (arr) in
  print("Inside the function callback  / trailing closure " , arr)
}
print("After calling the function") 

你错过了读什么

Answer 2

这是固定的示例：

func someFunctionThatTakesAClosure(closure: () -> Void) {
    // function body goes here
    print("we do something here and then go back")

    // don't forget to call the closure
    closure()
}


print("about to call function")

// call the function using trailing closure syntax
someFunctionThatTakesAClosure() {
    print("we did what was in the function and can now do something else")
}

print("after calling function")

输出：

 about to call function we do something here and then go back we did what was in the function and can now do something else after calling function