在viewDidLoad或某处尝试此操作.
原文链接：https://www.f2er.com/swift/319299.html在Swift 3中：
let pstyle = NSMutableParagraphStyle()
pstyle.alignment = .center
button.attributedTitle = NSAttributedString(string: "Title",attributes: [ NSForegroundColorAttributeName : NSColor.red,NSParagraphStyleAttributeName : pstyle ])
