Customizing QLPreviewController - iphone

Question

I have an issue in customizing the appearance of my QLPreviewController.
We can display a QLPreviewController by pushing it in a navigation controller, or presenting it in a ModalViewController. Since my navigationController's bar is customized a little (tintColor), I'm pushing the QLPreviewController to preserve my color scheme. But when I push it, the QLPreviewController seems to have some problems : I need to systematically call [qlpvc reloadData] so that my file is displayed.
In iOS [REDACTED], even with reloadData, nothing displays in the pushing way, (actually it displays but in a random way). So I decided it could be interesting to only use the reliable Modal way.
Soooo my point is that I want to present my QLPreviewController in a ModalViewController. It works great that way, but I can't customize the viewController appearance.
For example in a didSelectRowAtIndexPath if I do :
(I don't have my sources near to me so excuse me if I do a mistake)
QLPreviewController *qlpvc = [[QLPreviewController alloc] init];
qlpvc.dataSource = self; // Data Source Protocol & methods implemented of course
No need for delegate in my case so //qlpvc.delegate = self;
qlpvc.currentPreviewItemIndex = [indexPath.row];
// The following doesn't work :
[qlpvc.navigationController.navigationBar setTintColor:[UIColor redColor]];
// The following doesn't work too :
[qlpvc.modalViewController.navigationController.navigationBar setTintColor:[UIColor redColor]];
[self presentModalViewController:qlpvc animated:YES];
[qlpvc release];
tl ; dr version : How to manage to customize my modal QLPreviewController's appearance ? Especially the tintColor of the navigationBar ?
Thanks a lot.

Answer 1

This works, but I don't know if it will be rejected by Apple as it's not a published method and may break in future versions of the OS. Works in iOS6.
Add to the preview controller datasource method:
- (id <QLPreviewItem>)previewController:(QLPreviewController *)controller previewItemAtIndex:(NSInteger)index
{
for (id object in controller.childViewControllers)
{
if ([object isKindOfClass:[UINavigationController class]])
{
UINavigationController *navController = object;
navController.navigationBar.tintColor = [UIColor colorWithRed:0.107 green:0.360 blue:0.668 alpha:1.000];
}
}
NSString *pathToPdfDoc = [[NSBundle mainBundle] pathForResource:#"MyPDFFile" ofType:#"pdf"];
return [NSURL fileURLWithPath:pathToPdfDoc];
}

Answer 2

Subclass QLPreviewController and change the tintColor, et al in viewDidLoad:.

Answer 3

If you are trying to maintain simple styling such as tintColor throughout your app, you should consider using UIAppearance selectors on many UIView classes. The following example customizes all instances of UINavigationBar, including those displayed in QLPreviewController:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
//..
[self initAppearance];
return YES;
}
-(void)initAppearance{
UINavigationBar* defaultNavigationBar = [UINavigationBar appearance];
UIImage *backgroundImage = [UIImage imageNamed:#"MY_IMAGE.png"]
NSDictionary *defaultNavigationBarDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
[UIFont fontWithName:#"Futura-Medium" size:19], NSFontAttributeName,
[UIColor blueColor], UITextAttributeTextColor,
[UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.0f], UITextAttributeTextShadowColor,
[NSValue valueWithUIOffset:UIOffsetMake(0.0f, 2.0f)], UITextAttributeTextShadowOffset,
nil];
defaultNavigationBar.titleTextAttributes = defaultNavigationBarDictionary; //iOS5
//[defaultNavigationBar setBackgroundImage:backgroundImage forBarMetrics:UIBarMetricsDefault]; //iOS5
[defaultNavigationBar setBarTintColor:[UIColor redColor]]; //iOS7
[defaultNavigationBar setShadowImage:[[UIImage alloc] init]]; //iOS6, removes shadow
[defaultNavigationBar setTitleVerticalPositionAdjustment:0.0f forBarMetrics:UIBarMetricsDefault]; //iOS5
[defaultNavigationBar setBackIndicatorImage:[UIImage imageNamed:#"BACK_ARROW.png"]]; //iOS7
[defaultNavigationBar setBackIndicatorTransitionMaskImage:[UIImage imageNamed:#"BACK_ARROW.png"]]; //iOS7
}