Objective c UITextView和NSMutableAttributedText

UITextView

使用

NSAttributedString

时显示格式化文本：

NSAttributedString* s1 =
[[NSAttributedString alloc] initWithString:@"Hello there!"
                                attributes:@{NSForegroundColorAttributeName:[UIColor redColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleBody]}];
_textView.attributedText = s1;

但是，当我使用

NSMutableAttributedString

时，我看到附加的属性字符串没有格式化。仅显示初始化的字符串的格式

UIFont *font = [UIFont preferredFontForTextStyle:UIFontTextStyleBody]
    NSMutableAttributedString *emailBody = [[NSMutableAttributedString alloc] initWithString:@"" attributes:@{NSForegroundColorAttributeName:[UIColor redColor], NSFontAttributeName: font}];
if (_person.firstName.length > 0) {
    [emailBody appendAttributedString:[[NSAttributedString alloc]initWithString:_person.firstName attributes:@{NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleCaption1]}]];
    [emailBody appendAttributedString:[[NSAttributedString alloc]initWithString:@"\n" attributes:nil]];
}
if (_person.lastName.length > 0) {
    [emailBody appendAttributedString:[[NSAttributedString alloc]initWithString:_person.lastName attributes:@{NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleCaption2]}]];
    [emailBody appendAttributedString:[[NSAttributedString alloc]initWithString:@"\n" attributes:nil]];
}

---

为什么？

当

NSAttributedString

附加到

NSMutableAttributedString

时，它有自己的属性。

当

NSAttributedString

附加到

NSMutableAttributedString

时，它有自己的属性