Cannot Convert Value of Type '[String:Anyobject]' to Expected Argument Type '[Nsattributedstringkey:Any]'

Cannot convert value of type '[String : AnyObject]?' to expected argument type '[NSAttributedStringKey : Any]?'

This is a new feature of Swift 4. All the Cocoa methods that take string identifiers and/or dictionary keys now have their own types for the keys. The reason for this is to add a bit of type safety—in the old regime, it was possible to accidentally pass a String constant by mistake that was meant to be used with some other API, but now in Swift 4, this will result in a compilation error.

Change your method signature to:

open class func drawText(context: CGContext, text: String, point: CGPoint,
    align: NSTextAlignment, attributes: [NSAttributedString.Key : Any]?)

EDIT: Updated for Swift 4.2! NSAttributedStringKey has been renamed to NSAttributedString.Key.

Swift 4 Cannot convert value of type '[String : AnyObject]?' to expected argument type '[NSAttributedStringKey : Any]?'

It's a type mismatch: [String : AnyObject] is clearly not [NSAttributedStringKey : Any]

⌥-click on NSAttributedStringKey to see the declaration.

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The solution is to declare attributes as

var attributes = [NSAttributedStringKey : Any]()

to remove the down cast

 ..., withAttributes: attributes)

and to write simply

attributes = [.foregroundColor: fieldColor,
              .font: fieldFont!,
              .paragraphStyle: style]

Cannot convert value of type 'NSAttributedString.Key' to expected dictionary key type 'String' error(swift4.2)

In Swift 4.2 you have to use NSAttributedString.Key instead of String

let lineattribute : [NSAttributedString.Key : Any] = [
    .foregroundColor : UIColor(hexString: "#0f88b7ff"),
    .underlineStyle : NSUnderlineStyle.styleSingle.rawValue
]

let attributeString = NSMutableAttributedString(string: "View traveling details", attributes: lineattribute)

Swift 4 conversion error: Cannot convert value of type 'String' to expected argument type 'NSAttributedStringKey'

You need to remove the use of .rawValue for the .paragraphStyle key.

Also note that for Swift 4.2 (or later) you need to replace any use of NSAttributedStringKey with NSAttributedString.Key.

DBL_MAX is deprecated. Use .greatestFiniteMagnitude instead of CGFloat(DBL_MAX).

Force-unwrapping the optional lineBreakMode parameter is going to cause your app to crash if nil is passed in.

Cannot subscript a value of type '[NSAttributedStringKey : Any]' with an index of type 'String'

In Swift 4 - NSAttributedString representation is changed.

The types are not [String: AnyObject] anymore. Its [NSAttributedStringKey:Any]

So your attributes should accessed like this:

if let attrs = attributes[NSAttributedStringKey.init("YYTextHighlight")] as? YYTextHighlight

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