iOS中UILabel显示不同的字体和颜色

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"S/A/T"];
// S
if ([model.toneTitle containsString:@"S"]) {
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:35/255.0 green:198/255.0 blue:136/255.0 alpha:1.000] range:NSMakeRange(0, 1)];
}
else
{
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:137/255.0 green:137/255.0 blue:137/255.0 alpha:1.000] range:NSMakeRange(0, 1)];
}
// "/"
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:35/255.0 green:198/255.0 blue:136/255.0 alpha:1.000] range:NSMakeRange(1, 1)];

// A
if ([model.toneTitle containsString:@"A"]) {
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:35/255.0 green:198/255.0 blue:136/255.0 alpha:1.000] range:NSMakeRange(2, 1)];
}
else
{
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:137/255.0 green:137/255.0 blue:137/255.0 alpha:1.000] range:NSMakeRange(2, 1)];
}

// "/"
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:35/255.0 green:198/255.0 blue:136/255.0 alpha:1.000] range:NSMakeRange(3, 1)];

// T
if ([model.toneTitle containsString:@"T"]) {
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:35/255.0 green:198/255.0 blue:136/255.0 alpha:1.000] range:NSMakeRange(4, 1)];
}
else
{
[string addAttribute:NSForegroundColorAttributeName value:[UIColor colorWithRed:137/255.0 green:137/255.0 blue:137/255.0 alpha:1.000] range:NSMakeRange(4, 1)];
}

//这里可以针对的设置字体大小（视情况而定）
//    [string addAttribute:NSFontAttributeName value:FONT([NSObject kevinFont:14]) range:NSMakeRange(0, 13)];
//    [string addAttribute:NSFontAttributeName value:FONT([NSObject kevinFont:14]) range:NSMakeRange(13, 17)];
//    [string addAttribute:NSFontAttributeName value:FONT([NSObject kevinFont:14]) range:NSMakeRange(30, 13)];

//对uilable进行赋值
self.labClass.attributedText = string;