Iphone – How to get a string into a format I can use with UIWebView loadRequest

I am using the UIWebView's canGoBack to check to see if I'm at the first page of the history. If I am then I just call the little method I used to load the first page (displayLocalResource sets up the HTMLString and loads it into the webView). Here is a snippet:

//Implementing a back button
- (void)backOne:(id)sender{
    if ([webView canGoBack]) {
        // There's a valid webpage to go back to, so go there
        [webView goBack];
    } else {
        // You've reached the end of the line, so reload your own data
            [self displayLocalResource];
        }
    }

probably it is better to use NSString and load html document as follows:

Objective-C

NSString *htmlFile = [[NSBundle mainBundle] pathForResource:@"sample" ofType:@"html"];
NSString* htmlString = [NSString stringWithContentsOfFile:htmlFile encoding:NSUTF8StringEncoding error:nil];
[webView loadHTMLString:htmlString baseURL: [[NSBundle mainBundle] bundleURL]];

Swift

let htmlFile = NSBundle.mainBundle().pathForResource("fileName", ofType: "html")
let html = try? String(contentsOfFile: htmlFile!, encoding: NSUTF8StringEncoding)
webView.loadHTMLString(html!, baseURL: nil) 

Swift 3 has few changes:

let htmlFile = Bundle.main.path(forResource: "intro", ofType: "html")
let html = try? String(contentsOfFile: htmlFile!, encoding: String.Encoding.utf8)
webView.loadHTMLString(html!, baseURL: nil)

Did you try?

Also check that the resource was found by pathForResource:ofType:inDirectory call.