How to restore subview of view controller using state restoration - ios

Question

I am using state restoration to restore previous views and data for my app.When a button is clicked in first view controller I am to pushing second view control.In this case I am able to restore second view controller data.But if I add second View Controller view as subview to first view controller when button is clicked in first view Controller, encodeRestorableStateWithCoder: and decodeRestorableStateWithCoder: were not called in second view controller.Unable to restore second view controller data.Do I need to do any other configurations to restore subview data ?
//Firstviewcontroller
-(IBAction)moveToNextViewController:(id)sender {
SecondVeiwController *sec_VC=[[SecondVeiwController alloc]initWithNibName:#"SecondVeiwController" bundle:[NSBundle mainBundle ]];
sec_VC.restorationIdentifier=#"SecondVeiwController";
[self.view addSubview:tab_cnt_1.view];
}
//Secondviewcontroller
-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
self.restorationIdentifier=#"Secondviewcontroller";
self.restorationClass=[self class];
}
return self;
}
+(UIViewController *)viewControllerWithRestorationIdentifierPath:(NSArray *)identifierComponents coder:(NSCoder *)coder
{
UIViewController * myViewController =
[[Secondviewcontroller alloc]
initWithNibName:#"Secondviewcontroller"
bundle:[NSBundle mainBundle]];
return myViewController;
}

Answer 1

It seems that iOS does not keep track of subviews, you have to encode the SecondViewController and then decode and add it as a child view controller with its view as a subview.
//FirstViewController
-(void)encodeRestorableStateWithCoder:(NSCoder *)coder {
[super encodeRestorableStateWithCoder:coder];
[coder encodeObject:self.childViewControllers[0] forKey:#"childVC"];
}
-(void)decodeRestorableStateWithCoder:(NSCoder *)coder {
[super decodeRestorableStateWithCoder:coder];
UIViewController *v = [coder decodeObjectForKey:#"childVC"];
[self addChildViewController:v];
[self.view addSubview:v.view];
}
//SecondViewController
-(void)encodeRestorableStateWithCoder:(NSCoder *)coder {
[super encodeRestorableStateWithCoder:coder];
[coder encodeObject:self.view.backgroundColor forKey:#"bgColor"];
}
-(void)decodeRestorableStateWithCoder:(NSCoder *)coder {
[super decodeRestorableStateWithCoder:coder];
UIColor *bgColor = [coder decodeObjectForKey:#"bgColor"];
[self.view setBackgroundColor:bgColor];
}