有没有办法在iOS 8中加速HTML到NSAttributedString的渲染？

Question

我可能是错的，但它似乎很多慢于它在iOS的7这一切都无法使用，但在生产与iOS 8

以下行：

NSString *htmlString = @"<em>emphasis</em> with some <strong>bolder text</strong>"; 
[[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUTF8StringEncoding] options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: @(NSUTF8StringEncoding)} documentAttributes:nil error:nil]; 

注意到0.48秒执行。半秒钟来解析两个简单的HTML标签。

但我不知道是否有一些奇怪的事情，因为如果我使用的HTML字符串：

NSString *htmlString = @"<em>emphasis</em> with some <strong>bolder text</strong> and <a href='http://google.ca'>google</a> with some <sup>superscript</sup> and some <sub>subscript</sub> and a <h1>header</h1> followed by some <strong><em>nested bold and italics</em></strong> plus some <em>neato</em> and some more <a href='#'>well then</a> with a bit of <del>strikethrough</del> and other text <em>emphasis</em> with some <strong>bolder text</strong> and <a href='http://google.ca'>google</a> with some <sup>superscript</sup> and some <sub>subscript</sub> and a <h1>header</h1> followed by some <strong><em>nested bold and italics</em></strong> plus some <em>neato</em> and some more <a href='#'>well then</a> with a bit of <del>strikethrough</del> and other text <em>emphasis</em> with some <strong>bolder text</strong> and <a href='http://google.ca'>google</a> with some <sup>superscript</sup> and some <sub>subscript</sub> and a <h1>header</h1> followed by some <strong><em>nested bold and italics</em></strong> plus some <em>neato</em> and some more <a href='#'>well then</a> with a bit of <del>strikethrough</del> and other text <em>emphasis</em> with some <strong>bolder text</strong> and <a href='http://google.ca'>google</a> with some <sup>superscript</sup> and some <sub>subscript</sub> and a <h1>header</h1> followed by some <strong><em>nested bold and italics</em></strong> plus some <em>neato</em> and some more <a href='#'>well then</a> with a bit of <del>strikethrough</del> and other text <em>emphasis</em> with some <strong>bolder text</strong> and <a href='http://google.ca'>google</a> with some <sup>superscript</sup> and some <sub>subscript</sub> and a <h1>header</h1> followed by some <strong><em>nested bold and italics</em></strong> plus some <em>neato</em> and some more <a href='#'>well then</a> with a bit of <del>strikethrough</del> and other text"; 

这是一个HTML字符串33X长，它需要0.51秒。

因此字符串是33X长，但需要较长的时间只有1.06倍（即0.03秒的时间）来渲染。

仅仅是一个荒谬的启动时间，我可以减轻不知何故？这看起来好像渲染时间非常不合理，而在iOS 7中，我几乎可以记住它是瞬时的。

_{如果没有，对NSAttributedString解决方案的替代HTML的任何建议？}

Answer 1

不幸的是，使用内置框架将文本从HTML转换为NSAttributedText具有不可接受的性能。你应该考虑使用第三方库，比如DCCoreText。

https://github.com/Cocoanetics/DTCoreText