为UIAlertAction编写处理程序 [英] Writing handler for UIAlertAction

问题描述

我正在向用户展示 UIAlertView ，我无法弄清楚如何编写处理程序。这是我的尝试：

I'm presenting a UIAlertView to the user and I can't figure out how to write the handler. This is my attempt:

let alert = UIAlertController(title: "Title",
                            message: "Message",
                     preferredStyle: UIAlertControllerStyle.Alert)

alert.addAction(UIAlertAction(title: "Okay",
                              style: UIAlertActionStyle.Default,
                            handler: {self in println("Foo")})

我在Xcode中遇到了很多问题。

I get a bunch of issues in Xcode.

文档说便利init（标题：String！，样式：UIAlertActionStyle，处理程序处理程序：（（UIAlertAction！） - > Void）！）

目前整个区块/关闭都有点过头了。任何建议都非常感谢。

The whole blocks/closures is a little over my head at the moment. Any suggestion are much appreciated.

推荐答案

而不是自己在你的处理程序中，put（alert：UIAlertAction！）。这应该使你的代码看起来像这样

Instead of self in your handler, put (alert: UIAlertAction!). This should make your code look like this

    alert.addAction(UIAlertAction(title: "Okay",
                          style: UIAlertActionStyle.Default,
                        handler: {(alert: UIAlertAction!) in println("Foo")}))

这是在Swift中定义处理程序的正确方法。

this is the proper way to define handlers in Swift.

正如Brian指出的那样，有还有更简单的方法来定义这些处理程序。书中讨论了使用他的方法，请看标题为Closures

As Brian pointed out below, there are also easier ways to define these handlers. Using his methods is discussed in the book, look at the section titled Closures

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