Issue in iOS7, fine in iOS6 - ios

Question

Below is the error i am getting in my app, which is working fine in ios6.
[__NSCFString frame]: unrecognized selector sent to instance 0xc075290
I am not getting what is wrong in it. But i guess something related to UINavigationController. Please guide for above.
Thanks in advance.
UPDATE: After enabling Zombies i get this error.
[_UINavigationBarBackIndicatorView frame]: message sent to deallocated instance 0xc0fb860
-(void)viewWillAppear:(BOOL)animated
{
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"isAcceptTerms"]) {
[adBannerView setDelegate:self];
[adBannerView setHidden:NO];
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"isBannerShown"]) //-ive logic is applied
{
[self.adBannerView setHidden:YES];
[self.adBannerView setDelegate:nil];
}
}
else
{
[adBannerView setDelegate:nil];
[adBannerView setHidden:YES];
}
[self.navigationController.navigationBar setHidden:NO];
NSMutableDictionary *dictTemp =[[sqlmessenger shared]fetchOrders];
int count=[[sqlmessenger shared] isuserdetails];
if (count>0)
{
[self updateCoordinate];
}
NSArray *arrContorl = [self.navigationController.navigationBar subviews];
for(UIButton *btnTemp in arrContorl)
{
if([btnTemp isKindOfClass:[UIButton class]])
{
[btnTemp removeFromSuperview];
}
}
UIImageView *imgHeader= [[UIImageView alloc]initWithFrame:CGRectMake(0,0,320,44)];
[imgHeader setBackgroundColor:[UIColor clearColor]];
[imgHeader setImage:[UIImage imageNamed:#"setting.png"]];
[self.navigationController.navigationBar addSubview:imgHeader];
if(lblHeader)
{
lblHeader=nil ;
}
lblHeader = [[UILabel alloc]initWithFrame:CGRectMake(60,5,230,30)];
[lblHeader setBackgroundColor:[UIColor clearColor]];
[lblHeader setTextAlignment:UITextAlignmentLeft];
[lblHeader setTextColor:[UIColor whiteColor]];
[lblHeader setFont:[UIFont boldSystemFontOfSize:18.0]];
if([dictTemp count]==0 && contentView.hidden == FALSE)
{
[lblHeader setText:#"Terms of Service (EULA)"];
}
else
{
[lblHeader setFrame:CGRectMake(110,5,200,30)];
[lblHeader setFont:[UIFont boldSystemFontOfSize:20.0]];
[lblHeader setText:#"Settings"];
}
[self.navigationController.navigationBar addSubview:lblHeader];
}

Answer 1

Obviously, you are trying to access the frame property of a NSString object, which is not permitted, since this object does not have this property.
Try adding more details. (Add the code that causes the crash, usually crash stack are not that helpful).
UPDATE:
Still not sure what's going on, you need to do the actual debug, plant the necessary breakpoints log your variables, see what values they have etc.
I can give you some things you can try:
1.Not sure why are you adding subviews to the navigation bar. You can instead use the navigationItem property of the UIViewController, and then leftBarButtonItem of UINavigationItem, like :
For left bar button item : (make sure you hide the back button first)
self.navigationController.navigationItem.hidesBackButton = YES;
self.navigationItem.leftBarButtonItem = yourLeftBarButtonItem;
And for the right one :
self.navigationItem.rightBarButtonItem = yourRightBarButtonItem;
2.You're allocating the view and the label each time that viewController is appearing. That's inefficient. Both memory and time-wise. Instead, you can allocate them once and change the alpha channels.