IOS 按钮富文本颜色显示不出来问题

[btn setTitle:@"0" forState:UIControlStateNormal];

[btn setTitleColor:__kColorOrange forState:UIControlStateNormal];

btn.titleLabel.numberOfLines = 2;

[btn setAttributedTitle:[self attributeStr:[NSString stringWithFormat:@"%@\n%@年建",_secHouseDetail.area,_secHouseDetail.buildYear] rangeOfString:[NSString stringWithFormat:@"%@年建",_secHouseDetail.buildYear] textColor:__kColorGray textFont:__kFontSuperMinSize] forState:UIControlStateNormal];

按照这样写的顺序就可以显示了，就是顺序问题