使用JavaScript将CSS注入UIWebView [英] Injecting CSS into UIWebView using JavaScript

问题描述

我正在尝试注入一个本地CSS文件来覆盖网页的样式。该网页显示在iOS中的 UIWebView 容器中。但是我无法让我的代码工作。请参阅下面的委托方法的片段。此代码运行（我可以看到 NSLog 消息），但我没有在页面上看到它的执行结果。

I am attempting to inject a local CSS file to override the styling of a webpage. The webpage is presented in a UIWebView container in iOS. However I am not able to get my code to work. See the snippet of my delegate method below. This code runs (I can see the NSLog message) but I do not see the results of it's execution on the page.

我知道它不能是我写的CSS，因为在这种情况下我把页面自己的CSS文件改成了一些颜色。 （为了测试这种方法）

I know it can't be the CSS I wrote because in this case I took the pages own CSS file and simply changed some colors. (In order to test this method)

-(void)webViewDidFinishLoad:(UIWebView *)webView 
{
    NSString *path = [[NSBundle mainBundle] bundlePath];
    NSString *cssPath = [path stringByAppendingPathComponent:@"reader.css"];
    NSString *js = [NSString stringWithFormat:@"var headID = document.getElementsByTagName('head')[0];var cssNode = document.createElement('link');cssNode.type = 'text/css';cssNode.rel = 'stylesheet';cssNode.href = '%@';cssNode.media = 'screen';headID.appendChild(cssNode);", cssPath];
    [webView stringByEvaluatingJavaScriptFromString:js];
    NSLog(@"webViewDidFinishLoad Executed");
}

推荐答案

您的解决方案不起作用因为

Your solution won't work because

1. 你的 cssNode.href 应该是一个URL（即转义并加上前缀 file：// ），而非路径


2. Safari不允许您从远程页面加载本地文件，因为它是安全风险。

1. your cssNode.href should be a URL (i.e. escaped and prefixed with file://), not a path
2. Safari doesn't let you load local files from a remote page, as it's a security risk.

过去我通过使用NSURLConnection下载HTML，然后添加<$ c $来完成此操作HTML头中的c>< style> 标记。类似于：

In the past I've done this by downloading the HTML using an NSURLConnection, and then adding a <style> tag in the HTML head. Something like:

NSString *pathToiOSCss = [[NSBundle mainBundle] pathForResource:@"reader" ofType:@"css"];
NSString *iOSCssData = [NSString stringWithContentsOfFile:pathToiOSCss encoding:NSUTF8StringEncoding error:NULL];
NSString *extraHeadTags = [NSString stringWithFormat:@"<style>%@</style></head>", iOSCssData];
html = [uneditedHtml stringByReplacingOccurrencesOfString:@"</head>" withString:extraHeadTags];

[webView loadHTMLString:html baseURL:url];

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