条件绑定的初始化程序必须具有可选类型，而不是'String'

问题描述

在更新为Swift 2.0

错误在if let url = URL.absoluteString行

func myFormatCompanyMessageText(attributedString: NSMutableAttributedString) -> NSMutableAttributedString
{
    // Define text font
    attributedString.addAttribute(NSFontAttributeName, value: UIFont(name: "Montserrat-Light", size: 17)!, range: NSMakeRange(0, attributedString.length))

    return attributedString
}

func textView(textView: UITextView, shouldInteractWithURL URL: NSURL, inRange characterRange: NSRange) -> Bool {
    if let url = URL.absoluteString {
        if #available(iOS 8.0, *) {
            VPMainViewController.showCompanyMessageWebView(url)
        }
    }
    return false
}

推荐答案

编译器告诉您不能使用if let，因为它完全没有必要.您没有要解包的任何可选内容:URL不是可选的，并且absoluteString属性也不是可选的. if let仅用于解开可选内容.如果要创建一个名为url的新常量，请执行以下操作:

The compiler is telling you that you can't use an if let because it's totally unnecessary. You don't have any optionals to unwrap: URL is not optional, and the absoluteString property isn't optional either. if let is used exclusively to unwrap optionals. If you want to create a new constant named url, just do it:

func textView(textView: UITextView, shouldInteractWithURL URL: NSURL, inRange characterRange: NSRange) -> Bool {
    let url = URL.absoluteString
    if #available(iOS 8.0, *) {
        VPMainViewController.showCompanyMessageWebView(url)
    }
    return false
}

但是，旁注:具有一个名为URL的参数和一个名为url的局部常量会令人感到困惑.这样您可能会更好:

However, sidenote: having a parameter named URL and a local constant named url is mighty confusing. You might be better off like this:

func textView(textView: UITextView, shouldInteractWithURL URL: NSURL, inRange characterRange: NSRange) -> Bool {
    if #available(iOS 8.0, *) {
        VPMainViewController.showCompanyMessageWebView(URL.absoluteString)
    }
    return false
}

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