无法将类型“[String : AnyObject]?.Type”（又名“Optional<Dictionary<String, AnyObject>>.Type）的值转换为预期的参数类型

Question

在 size = text.boundingRectWithSize

上收到此错误

Cannot convert value of type '[String : AnyObject]?.Type' (aka 'Optional>.Type) to expected argument type '[String : AnyObject]?'

func heightOfString(text: NSString!, width: CGFloat, font: UIFont) -> CGFloat{
    var ch:CGFloat!
    var size:CGSize = CGSizeMake(width, CGFloat.max)

    var tdic:NSDictionary = NSDictionary(objects: [font, NSFontAttributeName], forKeys: [])
    size = text.boundingRectWithSize(size, options: NSStringDrawingOptions.UsesFontLeading , attributes: [String : AnyObject]?, context: nil).size
    ch = size.height
    return ch

}

Answer 1

如果需要为属性传递空字典，请使用[:]

size = text.boundingRectWithSize(size, options: NSStringDrawingOptions.UsesFontLeading , attributes: [:], context: nil).size

无法将类型“[String : AnyObject]?.Type”（又名“Optional<Dictionary<String, AnyObject>>.Type）的值转换为预期的参数类型

Cannot convert value of type '[String : AnyObject]?.Type' (aka 'Optional<Dictionary<String, AnyObject>>.Type) to expected argument type

xcode

optional

ios

swift