ios, navigationbar is overlapped with its content view

I'm presenting a viewcontroller like below, and the presented view controller's content overlaps the navigationbar of its own.

MyViewController *myViewController = [[MyViewController alloc] initWithNibName:nil bundle:nil];
UINavigationController *navigationController = 
    [[UINavigationController alloc] initWithRootViewController:myViewController];

//now present this navigation controller modally 
[self presentViewController:navigationController
                   animated:YES
                   completion:^{

                        }];

I can probably fix it by adjusting the contentView's frame origin/size but, is there an easier way?

self.webview is the contentview, and I used to have the following code to fit the webview to the entire screen - navigationbar - statusbar. (which worked well when I just pushedViewController)

self.webview.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
[self.view addSubview:self.webview];
self.webview.frame = self.webview.superview.bounds;

enter image description here

Solution

Please add following lines in your viewDidLoad method:

self.navigationController.navigationBar.translucent = YES; 
self.edgesForExtendedLayout = UIRectEdgeNone;