輸入'String！' 不符合協議'Equatable'

Question

如何在swift iOS 8.0中解決這個問題，即輸入Type 'String!' does not conform to protocol 'Equatable' Type 'String!' does not conform to protocol 'Equatable'

這是我的代碼

func connection(connection: NSURLConnection, canAuthenticateAgainstProtectionSpace protectionSpace: NSURLProtectionSpace?) -> Bool
{
    return protectionSpace?.authenticationMethod == NSURLAuthenticationMethodServerTrust
// Here I got this error near == sign
}

func connection(connection: NSURLConnection, didReceiveAuthenticationChallenge challenge: NSURLAuthenticationChallenge?)
{
    if challenge?.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust
    {
        if challenge?.protectionSpace.host == "www.myhost.com"

// Here I got this error near == sign

        {
            let credentials = NSURLCredential(forTrust: challenge!.protectionSpace.serverTrust)
            challenge!.sender.useCredential(credentials, forAuthenticationChallenge: challenge)
        }
    }

    challenge?.sender.continueWithoutCredentialForAuthenticationChallenge(challenge)
}

Answer 1

我不同意有關簡單升級到最新版本的解決方案的評論。 在進行其他比較之前，使用零檢查解包選項是一種更好的做法 。 我會重寫你的代碼（盡管比需要的更冗長），如下所示，這也應該在所有版本中修復你的問題：

func connection(connection: NSURLConnection, canAuthenticateAgainstProtectionSpace protectionSpace: NSURLProtectionSpace?) -> Bool
{
    if let authenticationMethod = protectionSpace?.authenticationMethod 
    {
        return authenticationMethod == NSURLAuthenticationMethodServerTrust
    }

    return false
}

func connection(connection: NSURLConnection, didReceiveAuthenticationChallenge challenge: NSURLAuthenticationChallenge?)
{
    if let authenticationMethod = challenge?.protectionSpace.authenticationMethod
    {
        if authenticationMethod == NSURLAuthenticationMethodServerTrust
        {
            if challenge?.protectionSpace.host == "www.myhost.com"
            {
                let credentials = NSURLCredential(forTrust: challenge!.protectionSpace.serverTrust)
                challenge!.sender.useCredential(credentials, forAuthenticationChallenge: challenge)
            }
        }
    }

    challenge?.sender.continueWithoutCredentialForAuthenticationChallenge(challenge)
}