Create UIView on previous UIViewController from another UIViewController - ios

Question

How can I create a UIView on my previous UIViewController after popping the current UIViewController.
On my previous UIViewController I have a function that can be accessed on other UIViewControllers:
-(void)setMovieCompare:(NSString *)_movieName {
NSLog(#"Movie Compare %#",_movieName);
UIView *vw2ndPlayer = [[UIView alloc] initWithFrame:CGRectMake(0, 44, 320, 166)];
[self.view addSubView:vw2ndPlayer];
}
Then on my current UIViewController I have:
VideoPlayerViewController *_VideoPlayerViewController = [[VideoPlayerViewController alloc] initWithNibName:nil bundle:nil];
[_VideoPlayerViewController setMovieCompare:mediaObject.name];
[self.navigationController popViewControllerAnimated:YES];
It is causing me a:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString appendString:]: nil argument'
*** First throw call stack:
(0x31a3e2a3 0x398a297f 0x31a3e1c5 0x31a0d773 0x72461 0x74077 0x33865595 0x7600b 0x7aa6d 0x3390828d 0x3398af81 0x3234c277 0x31a135df 0x31a13291 0x31a11f01 0x31984ebd 0x31984d49 0x3553b2eb 0x3389a301 0x6e89d 0x39cd9b20)
libc++abi.dylib: terminate called throwing an exception

Answer 1

That code crashes because it's trying to read the vc from a nibNamed:nil. Even if you got that working, it wouldn't work. The code isn't changing the VideoPlayerVC that pushed the current vc, it's just allocating a new one (trying to) and changing a view on that new one, which gets released right after that method finishes.
The way to see the presenting view controller in a navigation container is to access self.navigationController.viewControllers.
NSArray *vcs = self.navigationController.viewControllers;
VideoPlayerViewController *previousVC = vcs[MAX(0, vc.count-2)];
[previousVC setMovieCompare ...];
Reaching down the navigation array may not be the best thing, especially of other view controllers can present the current vc. An alternative design is the delegate pattern, where the VideoPlayerVC sets itself as the pushed vs's delegate before pushing.