UIWebView 显示用于加载的 UIActivityIndi​​cator，但在页面初始加载后忽略其他加载请求（例如 javascript 加载的广告）

Question

这是一个问答帖。为了通知我在浏览 StackOverflow 的数据库时看到的许多其他用户在这个问题上苦苦挣扎。这些用户都没有得到可靠的答案（而且他们中的大多数人几年前就提出了这个问题，所以我不打算发帖）。

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许多人苦苦挣扎的问题如下：

当您尝试在 UIWebView 中加载页面，然后该页面可能通过 iFrame 加载另一个页面或通过 javascript 加载广告时，您最终会再次调用页面加载函数，如果您使用的是 UIActivityIndi​​cator 它会再次被调用并惹恼您的用户。

解决此问题的方法是存储以前的 MainURL 并检查尝试加载的新 MainURL，如果它们匹配则忽略加载函数。 （下面我的答案中的示例代码）

**在网页已经真正加载后将调用webViewDidStartLoad方法的网页示例如下：www.speakeasy.net/speedtest/

Answer 1

//Define the NSStrings "lastURL" & "currentURL" in the .h file.
//Define the int "falsepositive" in the .h file. (You could use booleans if you want)
//Define your UIWebView's delegate (either in the xib file or in your code `<UIWebViewDelegate>` in .h and `webView.delegate = self;` in .m viewDidLoad)

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    lastURL = [NSString stringWithFormat:@"%@", webView.request.mainDocumentURL];
    if (falsepositive != 1) {
        NSLog(@"Loaded");
        //hide UIActivityIndicator
    } else {
        NSLog(@"Extra content junk (i.e. advertisements) that the page loaded with javascript has finished loading");
        //This method may be a good way to prevent ads from loading hehe, but we won't do that
    }
}

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType; {
    NSURL *requestURL = [request mainDocumentURL];
    currentURL = [NSString stringWithFormat:@"%@", requestURL]; //not sure if "%@" should be used for an NSURL but it worked..., could cast `(NSString *)` if we *really* wanted to...
    return YES;
}

- (void)webViewDidStartLoad:(UIWebView *)webView {
    if ([currentURL isEqualToString:lastURL]) {
        falsepositive = 1;
        NSLog(@"The page is loading extra content with javascript or something, ignore this");
    } else {
        falsepositive = 0;
        NSLog(@"Loading");
        //show UIActiviyIndicator
    }
}

//make sure you read the //comments// at the top of this code snippet so that you properly define your .h variables O:) Thanks!



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