PreLoad UIWebView on a not yet displayed UIViewController

Question

I have an app where on the very last UIViewController there is a UIWebView... the user navigates through the app and at the very end they can transition (modal) to the final UIViewController with a UIWebView... in it's viewDidLoad I have the UIWebView load the page.

The problem is it takes about 8 seconds to load this page and that annoys users.

How can I load the UIWebView way ahead of time (like when the app is first launched!) if that UIViewController hasn't even been presented yet?

Answer 1

I had your same problem for UIWebView inside a UIPageViewController and I found a better solution.

If you are in FirstViewController and you have your webView in your SecondViewController put the loadHTMLString or loadRequest method in the viewDidLoad of your SecondViewController and call [secondViewController.view layoutSubviews] for start loading in your FirstViewController.

Ex:

FirstViewController

-(void)viewDidLoad{
    [super viewDidLoad];
    // _secondViewController -> An instance of SecondVieController
    [_secondViewController.view layoutSubviews];
}

SecondViewController

-(void)viewDidLoad{
    [super viewDidLoad];
    NSURL *url =[NSURL URLWithString:@"http://www.google.it"];
    NSURLRequest *request =[NSURLRequest requestWithURL:url];
    [self.webView loadRequest:request];
}

Answer 2

What u can do is, load the html string

 NSString *htmlFile = [[NSBundle mainBundle] pathForResource:self.path ofType:@"htm"];
 NSError * error;
 NSString* htmlString = [NSString stringWithContentsOfFile:htmlFile encoding:NSUTF8StringEncoding error:&error];

and when u display the webView load this content in your webView

[self.webView loadHTMLString:htmlString baseURL:[[NSBundle mainBundle] bundleURL]];

then your webview need only render your content and doesn't load the data

/// In Swift 2.0

    do{
        let path = NSBundle.mainBundle().pathForResource("theName", ofType: "html")!
        let html = try String(contentsOfFile: path, encoding: NSUTF8StringEncoding)
        webView.loadHTMLString(html, baseURL: nil)
    }catch{
        print("Error is happend")
    }

Note: It works the same way for WKWebView