我怎样才能改变iOS的字体颜色和字体样式的ePub图书的？(How can I change fon

我创建的图书应用，它支持PDF和ePub格式。在该应用程序，PDF格式只是示出作为图像和ePub在web视图打开，因为EPUB只是XHTML存储在与一个XML清单一个zip文件。现在，我要换的ePub书页字体样式和字体颜色 。可能吗？如果可能的话，那我怎么才能做到这一点？我寻觅了很多，但没有得到任何妥善的解决办法。

我已经找到了解决办法。我做一个字符串，并评估使用Java字符串

这是我写的：

NSString *varMySheet = @"var mySheet = document.styleSheets[0];";

NSString *addCSSRule =  @"function addCSSRule(selector, newRule) {"
"if (mySheet.addRule) {"
"mySheet.addRule(selector, newRule);"                               // For Internet Explorer
"} else {"
"ruleIndex = mySheet.cssRules.length;"
"mySheet.insertRule(selector + '{' + newRule + ';}', ruleIndex);"   // For Firefox, Chrome, etc.
"}"
"}";

NSString *insertRule1 = [NSString stringWithFormat:@"addCSSRule('html', 'padding: 0px; height: %fpx; -webkit-column-gap: 0px; -webkit-column-width: %fpx;')", webView.frame.size.height, webView.frame.size.width];
NSString *insertRule2 = [NSString stringWithFormat:@"addCSSRule('p', 'text-align: justify;')"];
NSString *setTextSizeRule = [NSString stringWithFormat:@"addCSSRule('body', '-webkit-text-size-adjust: %d%%;')", currentTextSize];
NSString *setHighlightColorRule = [NSString stringWithFormat:@"addCSSRule('highlight', 'background-color: yellow;')"];

    // this is what change the text style 

NSString *insertRule3 = [NSString stringWithFormat:@"addCSSRule('html, body, div, p, span, a', 'font-family: arial;')"];
NSString *changeColor = [NSString stringWithFormat:@"addCSSRule('html, body, div, p, span, a', 'color: #1122CC;')"];

[webView stringByEvaluatingJavaScriptFromString:varMySheet];

[webView stringByEvaluatingJavaScriptFromString:addCSSRule];

[webView stringByEvaluatingJavaScriptFromString:insertRule1];

[webView stringByEvaluatingJavaScriptFromString:insertRule2];

[webView stringByEvaluatingJavaScriptFromString:setTextSizeRule];

[webView stringByEvaluatingJavaScriptFromString:setHighlightColorRule];
    [webView stringByEvaluatingJavaScriptFromString:insertRule3];
    [webView stringByEvaluatingJavaScriptFromString:changeColor];