記得以前UIWebView 計(jì)算html文本的時(shí)候老是會(huì)有誤差
所以把這個(gè)貼出來(lái)，留著備用

原始數(shù)據(jù)：

把內(nèi)容放到NSAttributedString里來(lái)計(jì)算：

NSString *richText=@"<p>lfjkdlsajfdjsalf</p>";
NSAttributedString *attributeString=[[NSAttributedString alloc] initWithData:[richText dataUsingEncoding:NSUnicodeStringEncoding]
                                                                                                 options:@{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType}
                                                                                      documentAttributes:nil
                                                                                                   error:nil];

使用 NSString 的 boundingRectWithSize 方法來(lái)計(jì)算

NSRange range=NSMakeRange(0, attributeString.string.length);
NSDictionary *attribute=[attributeString attributesAtIndex:0 effectiveRange:&range];
CGRect rect=[attributeString.string boundingRectWithSize:CGSizeMake(SCREEN_WIDTH-30, 2000)
                                                                 options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading
                                                              attributes:attribute
                                                                 context:nil];