I have an html file named videoplay.html
with following content
Title
I had a similar issue. An html file called index.html in a sub-folder of the Documents directory called assets.
Documents/assets/index.html
...
Note that it's referencing other files in the assets directory. Namely, bundle.js and styles.css.
The following variation on the accepted answer's code example allowed the UIWebView to load index.html and have the js and css files it referenced still work:
NSArray *documentsPath = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask, YES);
NSString *assetsPath = [[documentsPath firstObject] stringByAppendingPathComponent:@"assets"];
NSString *indexHTMLFilePath = [assetsPath stringByAppendingPathComponent:@"index.html"];
NSString *encodedAssetsPath = [assetsPath stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *baseURL = [NSURL URLWithString:[NSString stringWithFormat:@"file:///%@/", encodedAssetsPath]];
NSData *indexHTMLFileData = [[NSFileManager defaultManager] contentsAtPath: indexHTMLFilePath];
[self.webView loadData:indexHTMLFileData MIMEType:@"text/html" textEncodingName:@"UTF-8" baseURL:baseURL];