我想将NSTextAttachment图像附加到我的属性字符串并使其垂直居中。我使用以下代码来创建我的字符串:NSMutableAttributedString*str=[[NSMutableAttributedStringalloc]initWithString:DDLocalizedString(@"title.upcomingHotspots")attributes:attrs];NSTextAttachment*attachment=[[NSTextAttachmentalloc]init];attachment.image=[[UIImageimageNamed:@"help
