如何从UIWebView获取内容？

Question

I need to get the first paragraph of each page from a UIWebView . How can I get this?

I have also one code for regular expression detection, but it gives the paragraph class name instead of paragraph contents:

NSError *error = NULL;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(<p\\s[\\s\\S]*?=\\s*?['\"](.*?)['\"][\\s\\S]*?>)+?"
                             options:NSRegularExpressionCaseInsensitive
                             error:&error];

[regex enumerateMatchesInString:html
                        options:0
                        range:NSMakeRange(0, [html length])
                        usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {

    NSString *img = [html substringWithRange:[result rangeAtIndex:2]];
    NSLog(@"img src %@",img);
}];

NSString *classs=[webView stringByEvaluatingJavaScriptFromString:@"document.getElementbyClassName(img)"];

Answer 1

The most robust way to do this is to execute some javascript code in the context of the web view which locates the first paragraph element in the document and returns its text. You can do this using UIWebView 's stringByEvaluatingJavaScriptFromString method.

The code below starts off by retrieving an array of all elements in the document with the tag name P (this assumes the text you are looking for is in these elements, if not you'll have more work to do). It then checks if there is at least one paragraph element, and if so, it returns its text content. Otherwise, it returns the empty string.

- (void)webViewDidFinishLoad:(UIWebView *)_webView
{
    NSString *code = @"var paragraphs = document.getElementsByTagName('P');"
                      "paragraphs.length > 0 ? paragraphs[0].innerText : '';";
    NSString *text = [_webView stringByEvaluatingJavaScriptFromString: code];
    // ... do something with text ...
}

You can run arbitrary javascript code in the context of the web view if you want to examine or change other aspects of the document.