如何使用 NSAttributedString w/ UILabel 进行描边和填充

两者都可以申请吗stroke and fill与NSAttributedString and a UILabel?

是的，关键是要申请Negative的价值NSStrokeWidthAttributeName如果该值为正数，您将只能看到描边而看不到填充。

Objective-C：

self.label.attributedText=[[NSAttributedString alloc] 
initWithString:@"string to both stroke and fill" 
attributes:@{
             NSStrokeWidthAttributeName: @-3.0,
             NSStrokeColorAttributeName:[UIColor yellowColor],
             NSForegroundColorAttributeName:[UIColor redColor]
             }
];

感谢下面的@cacau：另请参阅技术问答 QA1531 https://developer.apple.com/library/mac/qa/qa1531/_index.html

Swift 4版本：

let attributes: [NSAttributedStringKey : Any] = [.strokeWidth: -3.0,
                                                 .strokeColor: UIColor.yellow,
                                                 .foregroundColor: UIColor.red]

label.attributedText = NSAttributedString(string: text, attributes: attributes)

斯威夫特 5.1版本：

let attributes: [NSAttributedString.Key : Any] = [.strokeWidth: -3.0,
                                                  .strokeColor: UIColor.yellow,
                                                  .foregroundColor: UIColor.red]

label.attributedText = NSAttributedString(string: text, attributes: attributes)