iOS:How to open Another UINavigationController inside Existing UINavigationController? - ios

Question

I am facing crash with following code. The scenario is
This is my app delegate method in which i load RTC_HomeVC using UINavigationController.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
RTC_HomeVC *obj_RTC_HomeVC=[[RTC_HomeVC alloc]init];
UINavigationController *nav=[[UINavigationController alloc]initWithRootViewController:obj_RTC_HomeVC];
// Override point for customization after application launch.
self.window.rootViewController=nav;
[obj_RTC_HomeVC release];
[nav release];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
Now I want to open UINavigationController inside a parent Navigation controller. So i use a following code. The method -(IBAction)call_SectionFlow is in RTC_HomeVC.
-(IBAction)call_SectionFlow{
RTC_1_StoreDetailsVC *obj_StoreDetailsVC=[[RTC_1_StoreDetailsVC alloc]initWithNibName:#"RTC_1_StoreDetailsVC" bundle:nil];
RTC_3_EnablingWorksVC *obj_EnablingWorksVC = [[RTC_3_EnablingWorksVC alloc]initWithNibName:#"RTC_3_EnablingWorksVC" bundle:nil];
UINavigationController *navController_Sections = [[UINavigationController alloc] init];
NSArray *array_ControllerArray=[[NSArray alloc]initWithObjects:obj_StoreDetailsVC,obj_EnablingWorksVC, nil];
[navController_Sections setViewControllers:array_ControllerArray animated:FALSE]
navController_Sections.view.frame=CGRectMake(14, 40, 996,636 );
[self.view addSubview:[[[navController_Sections viewControllers] objectAtIndex:0] view]];
}
When i called this method application is crashed. This is crash log.
Crash log:
* Terminating app due to uncaught exception 'UIViewControllerHierarchyInconsistency', reason: 'child view controller:< RTC_1_StoreDetailsVC: 0x71f53a0 > should have parent view controller:< RTC_HomeVC: 0x758b310 > but actual parent is:< UINavigationController: 0x71f55d0 >'
* First throw call stack:
(0x1c9c012 0x10d9e7e 0x1c9bdeb 0x6838a 0x68739 0x6f5a3 0x67eed 0x4fc3 0x10ed705 0x24920 0x248b8 0xe5671 0xe5bcf 0xe4d38 0x5433f 0x54552 0x323aa 0x23cf8 0x1bf7df9 0x1bf7ad0 0x1c11bf5 0x1c11962 0x1c42bb6 0x1c41f44 0x1c41e1b 0x1bf67e3 0x1bf6668 0x2165c 0x1f82 0x1c45)
libc++abi.dylib: terminate called throwing an exception
So any one can tell me
What is wrong with this code? And which approach i should follow for resolving this crash ?
How to open another UINavigationController in existing UINavigationController?
Thanks.

Answer 1

Do not add subviews to UIWindow manually. It is not supported (or at least it does not work OK).
Use this method:
[firstNavigationVC presentViewController:secondNavigationVC animated:YES completion:nil];
What is causing crash is, that you are adding obj_StoreDetailsVC to the new navigation controller and then its view to self.view. Once a VC is child of another VC, its view must be descendant of that VC's view. Maybe you can add secondNavigationVC's view to to the view of firstNavigationVC, but that isn't how UIKit is supposed to work. Use the above method.