在我的应用程序中,我有一个按钮,按下该按钮后,您可以观看 youtube 视频(电影预告片)。在应用程序内,无需启动 safari。您可以在下面看到一个代码片段。此代码在 iOS5 下运行良好。但是,在 iOS 6 中,findButtonInView 中的 UIButton 始终为 nil。任何想法可能是什么原因?
youtubeWebView.delegate = self;
youtubeWebView.backgroundColor = [UIColor clearColor];
NSString* embedHTML = @" <html><head> <style type=\"text/css\"> body {background-color: transparent;  color: white; }</style></head><body style=\"margin:0\"><embed id=\"yt\" src=\"%@?version=3&app=youtube_gdata\" type=\"application/x-shockwave-flash\"width=\"%0.0f\" height=\"%0.0f\"></embed></body></html>";
NSURL *movieTrailer;
if(tmdbMovie) movieTrailer = tmdbMovie.trailer;
else movieTrailer = [NSURL URLWithString:movie.trailerURLString];
NSString *html = [NSString stringWithFormat:embedHTML,
                                            movieTrailer,
                                            youtubeWebView.frame.size.width,
                                            youtubeWebView.frame.size.height];
[youtubeWebView loadHTMLString:html baseURL:nil];
[self addSubview:youtubeWebView];
- (void)webViewDidFinishLoad:(UIWebView *)_webView {
    isWatchTrailerBusy = NO;
    [manager displayNetworkActivityIndicator:NO];
    //stop the activity indicator and enable the button
     UIButton *b = [self findButtonInView:_webView];
    //TODO this returns null in case of iOS 6, redirect to the youtube app
    if(b == nil) {
        NSURL *movieTrailer;
        if(tmdbMovie) {
            movieTrailer = tmdbMovie.trailer;
        } else {
            movieTrailer = [NSURL URLWithString:movie.trailerURLString];
        }
        [[UIApplication sharedApplication] openURL:movieTrailer];
    } else {
        [b sendActionsForControlEvents:UIControlEventTouchUpInside];
    }
}
- (UIButton *)findButtonInView:(UIView *)view {
    UIButton *button = nil;
    if ([view isMemberOfClass:[UIButton class]]) {
        return (UIButton *)view;
    }
    if (view.subviews && [view.subviews count] > 0) {
        for (UIView *subview in view.subviews) {
            button = [self findButtonInView:subview];
            if (button) return button;
        }
    }
     return button;
}