ios - 可以抛出调用，但未将其标记为“try”，并且未处理错误

嘿，社区我已经解决这个问题有一段时间了，还没有在网上找到一个与我的问题特别相关的解决方案。
我是swift语言的新手，我认为这个问题似乎与将NSString转换成String有关。
错误如下
无法转换'NSString'类型的值需要参数类型“String？”
关于我的

let file = PFFile(name: fileName, data: fileData!, contentType: fileType )

这里是整个功能

func uploadMessage() {
    var fileData: NSData?
    var fileName: NSString?
    var fileType: NSString?

    if image != nil {
        let newImage = resizeImage(image!, width: view.window!.frame.size.width, height: view.window!.frame.size.height)
        fileData = UIImagePNGRepresentation(newImage)
        fileName = "image.png"
        fileType = "image"
    } else {
        fileData = NSData.dataWithContentsOfMappedFile(videoFilePath! as String) as? NSData
        fileName = "video.mov"
        fileType = "video"
    }

    let file = PFFile(name: fileName, data: fileData!, contentType: fileType )

    file.saveInBackgroundWithBlock { (success: Bool, error: NSError!) -> Void in
        if error == nil {
            let message = PFObject(className: "Messages")
            message.setObject(file, forKey: "file")
            message.setObject(fileType!, forKey: "fileType")
            message.setObject(self.recipients!, forKey: "recipientIds")
            message.setObject(PFUser.currentUser()!.objectId!, forKey: "senderId")
            message.setObject(PFUser.currentUser()!.username!, forKey: "senderName")
            message.saveInBackgroundWithBlock({ (success: Bool, error: NSError!) -> Void in
                if error == nil {
                    //worked!
                    self.reset()
                } else {
                    UIAlertView(title: "Error", message: "Try agian", delegate: nil, cancelButtonTitle: "OK").show()
                }
            })
        } else {
            UIAlertView(title: "Error", message: "Try agian", delegate: nil, cancelButtonTitle: "OK").show()
        }
    }

提前感谢社区。

最佳答案

这个错误很明显。。。要么将fileName变量设为字符串（因为您使用的是Swift，所以无论如何您都应该这样做），要么在您要设置文件时，通过NSString将String转换为let file = PFFile(name: fileName as String, data: fileData!, contentType: fileType)
原始答案仍然有效，但您必须执行以下任一选项：

do {
    let file = try PFFile(name: fileName as String, data: fileData!, contentType: fileType)
} catch (_) {
    //this is the default catch which is exhaustive and will catch all errors. here you can find the specific error if you want, or just use this as a way to know the file wasn't created and to let the user know
}

关于ios - 可以抛出调用，但未将其标记为“try”，并且未处理错误，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/34294901/