Each YouTube video has four generated images. They are predictably formatted as follows:
https://img.youtube.com/vi/<insert-youtube-video-id-here>/0.jpg
https://img.youtube.com/vi/<insert-youtube-video-id-here>/1.jpg
https://img.youtube.com/vi/<insert-youtube-video-id-here>/2.jpg
https://img.youtube.com/vi/<insert-youtube-video-id-here>/3.jpg
The first one in the list is a full size image and others are thumbnail images. The default thumbnail image (i.e., one of 1.jpg, 2.jpg, 3.jpg) is:
https://img.youtube.com/vi/<insert-youtube-video-id-here>/default.jpg
For the high quality version of the thumbnail use a URL similar to this:
https://img.youtube.com/vi/<insert-youtube-video-id-here>/hqdefault.jpg
There is also a medium quality version of the thumbnail, using a URL similar to the HQ:
https://img.youtube.com/vi/<insert-youtube-video-id-here>/mqdefault.jpg
For the standard definition version of the thumbnail, use a URL similar to this:
https://img.youtube.com/vi/<insert-youtube-video-id-here>/sddefault.jpg
For the maximum resolution version of the thumbnail use a URL similar to this:
https://img.youtube.com/vi/<insert-youtube-video-id-here>/maxresdefault.jpg
All of the above URLs are available over HTTP too. Additionally, the slightly shorter hostname i3.ytimg.com works in place of img.youtube.com in the example URLs above.
Alternatively, you can use the YouTube Data API (v3) to get thumbnail images.
You can use this to load the movie (no needed to generate a html string):
movieView = [[UIWebView alloc] initWithFrame:CGRectMake(10, 10, 140, 100)];
movieView.delegate = self;
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.youtube.com/embed/-h4zTEwgCpQ"]];
[movieView loadRequest:request];
[self.view addSubview:movieView];
#pragma mark -
#pragma mark UIWebViewDelegate
//To check if youtube try to show the overview page of m.youtube.com or the current movie
//if the user click on the youtube logo this method stop loading the mobile page
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSURL *urlRequest = [request URL];
if ([[urlRequest absoluteString] isEqualToString:url]) {
return YES;
}
return NO;
}
The onely thing you have to looking for, is to use the "embed" link.
Best Answer
I've created a test project with following code executed:
Running the project in Simulator allowed to reproduced the issue you've stumbled upon: test app launched Safari and it simply opened the Youtube video's page. But when I ran the same project on an iPhone the result was different: it launched the Youtube app and it started lading/playing the video in the URL right away.
The reason why the same code behaves itself differently is that there's no Youtube app in Simulator, so the only URL handler available in its environment is Safari. So everything's working as it should, you can continue developing your app.
BTW here's a really nice official blog post from Youtube about integrating it with iPhone apps: YouTube APIs + iPhone = Cool mobile apps