ios title 加粗oc代码

可以使用NSAttributedString来设置title的样式，具体代码如下：

NSMutableAttributedString *attributedTitle = [[NSMutableAttributedString alloc] initWithString:@"Title"];
[attributedTitle addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:17.] range:NSMakeRange(, attributedTitle.length)];
self.navigationItem.titleView = [[UILabel alloc] init];
[(UILabel *)self.navigationItem.titleView setAttributedText:attributedTitle];
[(UILabel *)self.navigationItem.titleView sizeToFit];