闭包返回值（先前为completionBlock） [英] Closures return value (previously completionBlock)

问题描述

我想在长期操作完成后返回一些值。
但是我还想分裂逻辑和gui。

I'd like to return some values after the long term operation is completed. But furthermore I'd like to split the logic and the gui.

例如;我有两个班级

1. SomeServices.swift有一个名为getDataFromService ...的方法


2. MyTableViewController.swift将显示getDataFromService的结果

所以，以前在Objective-C中我只是添加一个方法在SomeServices中，如下所示：

So, previously in Objective-C I've just add a method in SomeServices like this:

(void)getDataFromService:(void (^)(NSArray *, NSError *))completionBlock{ ...... }

在这个方法中，我刚刚调用了 completionBlock （myData，myError）将我的值返回到tableviewcontroller。

In this method I've just called completionBlock(myData, myError) to return my values to the tableviewcontroller.

我必须在SomeServices.swift中定义的等效闭包是什么如何在MyTableViewController中调用它？

What would be the equivalent closure which I have to define in SomeServices.swift and how will it be called in MyTableViewController?

我知道如何调用这样的简单闭包：

I know how to call a simple closures like this one:

   ....({
            responseData, error  in
            if(!error){
                //Do something
            }
        })

但我对如何定义一个与completionBlock等效的闭包没有任何想法。

But I don't have any ideas how to define a closure with a completionBlock equivalent.

任何帮助将不胜感激

推荐答案

关闭的优点是，你可以传递你想要的一切。方法或函数 - 没关系。

The plus of closures are, that you can pass everything you want. Methods or functions - it doesn't matter.

你可以在参数中传递一个函数并调用它。

You can pass a function within the parameters and just call it.

func someFunctionThatTakesAClosure(completionClosure: () -> ()) {
    // function body goes here
    if(error = false) {
       completionClosure()
    }

}

//Call it
someFunctionThatTakesAClosure({
    //Completions Stuff
    println("someFunctionThatTakesAClosure")
});

摘自：Apple Inc.The Swift Programming Language。iBooks。 https://itun.es/ch/jEUH0.l

Excerpt From: Apple Inc. "The Swift Programming Language." iBooks. https://itun.es/ch/jEUH0.l

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