使用UIWebView中html标签显示富文本
用UIWebView来渲染文本并期望达到富文本的效果开销很大哦!
Work
本人此处直接加载自定义字体"新蒂小丸子体",源码不公开,望见谅.
代码如下:
渲染后效果如下图所示,效果是不是挺不错的呢.
我们再把尽头两个字渲染成红色试试.
源码:
- (void)viewDidLoad { [super viewDidLoad]; // 注册字体 REGISTER_FONT(bundleFont(@"XinDiXiaoWanZi.ttf"), @"新蒂小丸子体"); NSString *jsString = [NSString stringWithFormat: @"<html> " // 设置字体的css样式 "<head> " "<style type="text/css"> " "body {font-size: %f; font-family: "%@"; color: %@;} " "</style> " "</head> " // 字符串显示部分 "<body>%@</body> " "</html>", 37.f, // 字体大小 CUSTOM_FONT(@"新蒂小丸子体", 0), // 字体类型 @"#000000", // 字体颜色 @"走向世界的<span style="color:red;">尽头</span>!"]; UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 100, 320, 70)]; [webView loadHTMLString:jsString baseURL:nil]; [self.view addSubview:webView]; }
效果如下:
Question
Currently I am working on iOS client for web-chat. Thus chat messages have HTML tags (bold, italic, underlined, font color, images (smiles), etc.). For example:
最近,我要给一个网页聊天的网站做一个客户端.这些聊天信息包含了很多HTML标签(bold, italic, underlined, font color, images (smiles), etc.),例如:
<b>bold</b> <i>italic</i> <!--smile:bird--><img style="vertical-align: middle;border: none;" alt="bird" src="http://www.site.com/engine/data/emo_chat/bird.gif" /><!--/smile--> ordinaty text
For the moment I have 2 ideas how to display messages:
当下,我有两个思路来显示这些信息:
- Add UIWebView to tables cell. But I think that it's not an option, because we will have a lot of messages and a lot of WebViews. 将UIWebView添加到cell中,但这个备选方案问题多多,因为我有很火很多消息需要显示,同时也需要很多很多的WebView.
- Add UITextView to tables cell, parse HTML tags and make necessary changes to attributed string. But UITextView doesn't support images (if I am right). 将UITextView添加到cell中,解析HTML标签并转换成富文本标签.但是,UITextView不支持图片显示(如果我没猜错的话).
Is there any other (better) way to display such data (styled text + images)?
是否有其他更好的方式来显示富文本加图片呢?
Answer
Using a webview per-cell is not going to work as you suspect. Webviews take a noticeable time to render which means you will likely end up with old webview content being momentarily displayed in reused cells until the new content renders. Webview is also a pretty heavy-weight UI element and you will encounter performance issues with having many of them on the screen updating at once.
将webView添加到cell中绝对达不到你的预期.WebView需要很长很长时间来渲染,在cell中重用你就会死.WebView是开销非常大的UI控件.
You will want to parse the HTML text you are given into an attributed string using a library like DTCoreText. From here, if you can target iOS 6 or later you can set the attributedText property on a standard UILabel. If you need to target earlier iOS versions you can again use DTCoreText, specifically the DTAttributedLabel or DTAttributedTextCell components.
也许你需要 DTCoreText 来帮助你将HTML标签解析成富文本.
The parsing and NSAttributedString rendering can all be done manually using an XML parser and CoreText, but DTCoreText will make your life much easier.
虽然解析HTML以及富文本的渲染都可以通过手动的XML解析器以及CoreText来实现, 只不过 DTCoreText 让你更轻松而已.
Update: You mentioned in a comment that you want support for <img/>. DTCoreText does have some basic image support, but this is a really hard problem if you are rendering text with CoreText because you have to make text flow around the image correctly, and reserve some space in the core text renderer to put your image into. If there is just a single image for each cell, I would suggest you manually extract the image path/url and lay it out with a UIImageView alongside your text.
注意:你提到了一个要素就是想支持<img/>.DTCoreText 支持几种基本的image,但是如果你想用 CoreText 来实现这种图文混排的工作会让你非常蛋疼.如果你仅仅是展示一张图片到一个cell当中.我建议你直接用UIImageView来显示图片算了.