XCode Prevent UIWebView flashing white screen after Launch Image - xcode

Question

I am fairly new to XCode - I'm designing an app with a single view that just displays a UIWebView that loads my jQuery mobile web site.
I have the Default.png and Default#2x.png files for the Launch images in place. When I run the app on my test device or in the emulator, it shows my Launch Image, and then flashes a white screen while the UIWebView loads the first page.
I know that I can change the background color and opacity so it will flash a different color than white, but I would like to prevent the flash altogether. I would like the app to launch, show the Launch image, and not show the UIWebView until the first page has completely loaded. Help?

Answer 1

# Andreas Volz (and anyone else wondering how I solved the problem of the white "flash")
First, add the name-of-loading-image.png and name-of-loading-image#2x.png files to your Xcode project. The regular image should be 320 x 460, and the #2x image should be 640 x 920.
Then, in my ViewController.h file I added these properties:
#property (nonatomic, retain) UIWebView *webView;
#property(nonatomic, strong) UIImageView *loadingImageView;
#end
And then in my ViewController.m file I added this:
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController;
#synthesize webView;
#synthesize loadingImageView;
- (void)viewDidLoad
{
[super viewDidLoad];
//**************** Set website URL for UIWebView
[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.example.com"] cachePolicy:NSURLCacheStorageAllowed timeoutInterval:20.0]];
//**************** Add Static loading image to prevent white "flash" ****************/
UIImage *loadingImage = [UIImage imageNamed:#"name-of-loading-image.png"];
loadingImageView = [[UIImageView alloc] initWithImage:loadingImage];
loadingImageView.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"name-of-loading-image.png"],
nil];
[self.view addSubview:loadingImageView];
}
- (void)webViewDidFinishLoad:(UIWebView *)webView {
// Remove loading image from view
[loadingImageView removeFromSuperview];
}

Answer 2

To know when your webView has finished loading, you must implement the UIWebViewDelegate protocol.
In your viewController's .h file:
#interface viewController : UIViewController <UIWebViewDelegate>
{
UIWebView *webView;
}
#end
Then in your viewController's .m file, add this method:
- (void)webViewDidFinishLoad:(UIWebView *)webView {
NSLog(#"content loading finished");
// Display your webView
[self.view addSubview:webView];
}
You can use the -viewDidLoad method in your viewController's .m to continue displaying your launch image. You can also begin the loading of content for your webView:
- (void)viewDidLoad {
[super viewDidLoad];
// continue to display launch image
UIImage *launchImage = [[UIImage alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"launchImage.png" ofType:nil ]];
UIImageView *launchImageView = [[[UIImageView alloc] initWithImage:launchImage] autorelease];
[self.view addSubview:launchImageView];
// now setup the base view for the webView controller
UIView *contentView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
contentView.backgroundColor = [UIColor blueColor];
// for rotation
contentView.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
self.view = contentView;
//create a frame to size and place the web view
CGRect webFrame = [[UIScreen mainScreen] applicationFrame];
UIWebView *aWebView = [[UIWebView alloc] initWithFrame:webFrame];
self.webView = aWebView;
//aWebView.scalesPageToFit = YES;
aWebView.autoresizesSubviews = YES;
aWebView.autoresizingMask=(UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth);
//set the web view delegates for the web view to be itself
[aWebView setDelegate:self];
//determine the path the to the index.html file in the Resources directory
NSURL *url = [[NSBundle mainBundle] URLForResource:#"index" withExtension:#"html"];
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
[aWebView loadRequest:requestObj];
}