swift中的do catch语句中的错误

I'm trying to explore this new (for me) language, and I'm making an app that like many others retrieve some json data from a server. in this function (from a tutorial I found) I get 4 errors, and I'm unable to fix it:

我正在尝试探索这种新的（对我而言）语言，而我正在制作一个应用程序，就像许多其他人从服务器中检索一些json数据一样。在这个函数中（从我发现的教程）我得到4个错误，我无法解决它：

 func json_parseData(data: NSData) -> NSDictionary? {
    do {
    let json: AnyObject = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers)
    print("[JSON] OK!")
    return (json as? NSDictionary)
    }catch _ {
        print("[ERROR] An error has happened with parsing of json data")
        return nil

    }
}

the first one is at the "try", xcode suggest me to fix it using "try;" the others at the "catch" and are this others:

第一个是“尝试”，xcode建议我使用“try”修复它“抓住”中的其他人是其他人：

Braced block of statement is an unused closure
声明的声明块是未使用的闭包
Type of expression is ambiguous without more context
如果没有更多的上下文，表达的类型是不明确的
Expected while in do-while-loop
在do-while-loop期间预期

please help me to understand

请帮我理解

1 个解决方案

#1

It seems that you are using Xcode 6.x and Swift 1.x where the do-try-catch syntax is not available (only Xcode 7 and Swift 2)

您似乎正在使用Xcode 6.x和Swift 1.x，其中do-try-catch语法不可用（仅Xcode 7和Swift 2）

This code has equivalent behavior:

此代码具有等效行为：

func json_parseData(data: NSData) -> NSDictionary? {
    var error: NSError?

    // passing the error as inout parameter
    // so it can be mutated inside the function (like a pointer reference)
    let json: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainerserror: &error)

    if error == nil {
        print("[JSON] OK!")
        return (json as? NSDictionary)
    }
    print("[ERROR] An error has happened with parsing of json data")
    return nil
}

Note: as of Xcode 7 beta 6 you can also use try? which returns nil if an error occurs.

注意：从Xcode 7 beta 6开始你还可以试试吗？如果发生错误，则返回nil。

#1