Remove UIViewController from UINavigationController

NSMutableArray *allControllers = [[NSMutableArray alloc] initWithArray:navPick.viewControllers];	

for (id object in allControllers) {

	//		if ([object isKindOfClass:[LoginController class]]) // 此行註解掉，會將容器內所有VC移除

	[allControllers removeObject:object];

}		

navPick.viewControllers = allControllers;