CODEWITHSUNDEEP
swift4xcode9
Steblo
Steblo

Reputation: 625

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

I have just updated to Xcode 9 and converted my app from swift 3 to swift 4. I have graphs which use strings to label the axes and other variables. So I have a moneyAxisString = "Money". Previously I was able to draw them using this code:

moneyAxisString.draw(in: CGRect(x: CGFloat(coordinateXOriginLT + axisLength/3), y: CGFloat(coordinateYOriginRT + axisLength + 5 * unitDim), width: CGFloat(300 * unitDim), height: CGFloat(100 * unitDim)), withAttributes: attributes as? [String : AnyObject])

Where attributes is a dictionary defined as follows

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

    ]

Now my app won't compile and I am getting the message:

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

Upvotes: 5

Views: 18216

Answers (4)

bibscy
bibscy

Reputation: 2708

Swift 4.2
Built on example of user_Dennis

 func getCustomStringStyle() -> [NSAttributedString.Key: Any]
    {
        return [
            NSAttributedString.Key(rawValue: NSAttributedString.Key.font.rawValue): UIFont.systemFont(ofSize: 25), // or your fieldFont
            NSAttributedString.Key(rawValue: NSAttributedString.Key.foregroundColor.rawValue): UIColor.black, // or your fieldColor
            NSAttributedString.Key(rawValue: NSAttributedString.Key.paragraphStyle.rawValue): NSParagraphStyle.default // or your style
        ]
    }

Upvotes: 0

leanne
leanne

Reputation: 8719

NSAttributedStringKey was changed to a struct in Swift 4. However, other objects that use NSAttributedStringKey apparently didn't get updated at the same time.

The easiest fix, without having to change any of your other code, is to append .rawValue to all your occurrences of NSAttributedStringKey setters - turning the key names into Strings:

let attributes = [
    NSAttributedStringKey.font.rawValue:  UIFont(name: "Helvetica-Bold", size: 15.0)!,
    NSAttributedStringKey.foregroundColor.rawValue: UIColor.white
] as [String : Any]

Note that you won't need the ! at the as now, either.

Alternatively, you can skip the as cast at the end by declaring the array to be [String : Any] upfront:

let attributes: [String : Any] = [
    NSAttributedStringKey.font.rawValue:  UIFont(name: "Helvetica-Bold", size: 15.0)!,
    NSAttributedStringKey.foregroundColor.rawValue: UIColor.white
]

Of course, you still need to append the .rawValue for each NSAttributedStringKey item you set.

Upvotes: 3

user_Dennis_Mostajo
user_Dennis_Mostajo

Reputation: 2389

Try this:

class func getCustomStringStyle() -> [NSAttributedStringKey: Any]
    {
        return [
            NSAttributedStringKey(rawValue: NSAttributedStringKey.font.rawValue): UIFont.systemFont(ofSize: 16), // or your fieldFont
            NSAttributedStringKey(rawValue: NSAttributedStringKey.foregroundColor.rawValue): UIColor.black, // or your fieldColor
            NSAttributedStringKey(rawValue: NSAttributedStringKey.paragraphStyle.rawValue): NSParagraphStyle.default // or your style
        ]
    }

or:

class func getCustomStringStyle() -> [String: Any]
    {
        return [
            NSAttributedStringKey.font.rawValue: UIFont.systemFont(ofSize: 16),
            NSAttributedStringKey.foregroundColor.rawValue: UIColor.black,
            NSAttributedStringKey.paragraphStyle.rawValue:NSParagraphStyle.default
        ]
    }

Upvotes: 2

vadian
vadian

Reputation: 285069

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

⌥-click on NSAttributedStringKey to see the declaration.

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]

Upvotes: 11

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