继承UILabel ，重写text的set方法，上代码：

- (void)setText:(NSString *)text {
    [super setText:text];
    
    //将数字变成蓝色
    NSString *labelStr = self.text; //初始化string为传入label.text的值
    NSCharacterSet *nonDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
    NSInteger remainSeconde = [[labelStr stringByTrimmingCharactersInSet:nonDigits] integerValue];//获取过滤出来的数值
    NSString *stringRange = [NSString stringWithFormat:@"%ld",(long)remainSeconde];//将过滤出来的Integer的值转换成String
    NSRange range = [labelStr rangeOfString:stringRange];//获取过滤出来的数值的位置
    NSMutableAttributedString *attrStr = [[NSMutableAttributedString alloc]initWithString:self.text];
    [attrStr addAttribute:NSForegroundColorAttributeName value:AB_Color_0084FF range:range];
    self.attributedText = attrStr;
    
}