admob click after return it wrong layout - iphone

Question

I use cocos2d combined with AdMob , nomarl my app work great, but after hit the advertising and return the game, it wrong layout, my game is landscape!
Things changes after AdMob is involved. AdMob has a AD type "movie". After clicking the ad, it popups a full screen mode, and play a movie, and then back to the game. The game changes, originally, it is landscape mode, and after back from ad, it seems to be portrait mode, and the game is scaled, everything looks bad. I have tried to update the view controller / CCDirector after back from ad, but it doesn't work.
A workaround found: just rotate the device to the counterpart landscape mode and everything goes well again.
Just wonder if there is any way to prevent telling customers rotate it manually?
Have you encountered this before?
_viewController = [[UIViewController alloc] init];
_viewController.view = [[CCDirector sharedDirector] openGLView];
_admobView = [[GADBannerView alloc] initWithAdSize:kGADAdSizeBanner];
_admobView.adUnitID = ADMOB_PUBLISHER_ID;
_admobView.delegate = self;
GADRequest *request = [GADRequest request];
request.testing = YES;
[_admobView setRootViewController:_viewController];
[_admobView loadRequest:request];
[_viewController.view addSubview:_admobView];

Answer 1

I had a similar issue before, and the cause was that I created a new UIViewController and set it as rootViewController for AdMob view - just like what you are doing:
_viewController = [[UIViewController alloc] init];
_viewController.view = [[CCDirector sharedDirector] openGLView];
...
[_admobView setRootViewController:_viewController];
This leads to layout problems when returning from some kinds of advertisement. What I am doing now in my app is like:
adMobView.rootViewController = [RootViewController sharedInstance];
[[[CCDirector sharedDirector] openGLView] addSubview:adMobView];
where [RootViewController sharedInstance] is a class method which returns the only instance of RootViewController in the app. For details please refer to my answer to another question: https://stackoverflow.com/a/10222956/1241690
(For cocos2d 2.x, the second line should be:
[[[CCDirector sharedDirector] view] addSubview:adMobView];
)