iOS中富文本NSMutableAttributedString的用法

NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc]initWithString:@"我是富文本"];
//字体
[attrString addAttribute:NSFontAttributeName
value:[UIFont systemFontOfSize:12.0]
range:NSMakeRange(0, 2)];
//粗细 负为实体，正为中空
[attrString addAttribute:NSStrokeWidthAttributeName
value:@(-3)
range:NSMakeRange(0, attrString.length)];
//颜色
[attrString addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:NSMakeRange(0, attrString.length)];

[labelInstance setAttributedText:attrString];