I have to use a UITabBarController inside UINavigationController. Everything seems to be right, but if i log the dealloc calls of the tabs some strange thing happens.
If I don't touch eanything just the back button, all dealloc of each tabs are called.
If I switch to any other tab and than I tap the back button the dealloc of the first tab won't be called but the others will.
What can be wrong whit that?
Take a look at this SO question. Basically, a tab bar controller inside a nav controller isn't officially supported, but you can mimic the behavior by using a tab bar without a UITabBarController.
Related
I'm writing an iPhone app that is based on a UINavigationController. I'm pulling data from a server that sometime returns bogus links. I open each link by pushing a webview viewcontroller. I want to be able to include some error handling. I know if the link is no good. So I want to be able to pop the webview view controller as soon as I know that my webview has encountered an error.
Currently, I've tried using the following code:
[self.navigationController popViewControllerAnimated:YES];
I then get a Navigation bar with nothing displayed in it, but if I click where the "back" button should be it operates appropriately. The title pops up when I click where the "back" button should be. The view where the viewcontrollers usually display there content is blank white too even though I'm popping back to a UITableViewController.
I've tried this as a workaround:
UINavigationController *nav = self.navigationController;
[self.navigationController popViewControllerAnimated:YES];
[nav.visibleViewController.view setNeedsDisplay];
I've checked the viewControllers array in the UINavigationController and it has the right viewcontrollers in it (ie it has removed the viewcontroller for the webview).
I also tried putting code in the viewWillAppear of the viewcontroller I'm popping back to, but the method is never getting called.
I'm looking for a way to force the UINavigationController to reload the same way that you can call reloadData on a UITableView.
Any help would be greatly appreciated.
I saw something like this on my app where I was using a navigation bar I added in Interface Builder on the root view of a navigation controller and then programmatically creating the nav bar and its subviews for the second view. When I would pop the second view to return to the first view I would hide the self.navigationcontroller bar which would show the white space underneath until the IB nav bar of the previous view appeared. To fix this I decided to stick with programmatically creating all my navbars which fixed the issue for me.
TL;DR - if you are using both IB and programmatically made navbars this can happen when popping views, stick with one or the other for all the navbars yo
I am trying to write an iPhone app that has both a UITabBar controller (and its associated views) and a plain vanilla view controller that is not part of the TabBar (i.e. an initial config page that only gets displayed the first time the app is run).
I am able to put a Tab Bar Controller and a View Controller in MainWindow.xib and shuffle between the two in the app delegate.
While this works I'm wondering if this is the best way to be implementing this.
It doesn't feel very "MVC-ish" to me but I think the two different controllers both need to be root (?)
I don't know how else I would do it.
If the config page is really only a "run once" affair, you could just pop it as a modal view from within the tab bar controller via the presentModalViewController:animated: method. (If on the other hand the config page is ever likely to be required in the future, I'd just add it as another option on the UITabBar.)
You would make the tabbarcontroller the default view. And present the viewcontroller modally in viewWillAppear or similar method. Then when you want to switch to the tabbar, you'd dismiss the modal view controller.
I have a tabBar controller. Tapping the active tab, by default, calls popToRootViewController on that tab's navigation controller. That is what I want, but I also need to do some customization when this happens. The view controller in question has a nav controller, but is not a subclass of UINavigationController. How can I listen for when popToRootViewController occurs and take some action?
You can use UINavigationControllerDelegate's method:
– navigationController:didShowViewController:animated:
and check if the shown controller is the controller you want.
Hopes this helps
(I remember using this in iOS 2.x and it was a little bit buggy, I wonder if is ok now. It should be since it's 4 already)
You can put you code inside the method – tabBarController:didSelectViewController: of the UITabBarController delegate, or maybe inside the UIViewController's - viewWillAppear:animated: method.
Note:
If you have added your Tabbarcontroller in the navigation stack,
-(void)viewWillAppear:(BOOL)animated
would not be called in iOS 4.2 or below, I wasted so many days to figure out this.
I am using Tab bar + navigation based application and I have 4 tab bars. When I navigate from one view controller to another view controller, the viewWillAppear: method doesn't seem to respond and I am being forced to call it manually by creating the object of the next view controller. So my question is, how do I avoid calling the viewWillAppear: method manually whenever I navigate from one view controller to another? Instead, it should get triggered automatically just like the viewdidLoad: method gets triggered when you navigate from one view controller to other. Please guide me on how could I do that.
Hoping for the best possible Answer
Thanks in Advance
You are correct, viewWillAppear is a little special, it is usually called automatically but in some cases including when you are adding a view controllers view manually (view addSubview:), and also when adding this as a view controller to a UITabBarController or UINavigationCnotroller (of which you have both !) it doesn't get messaged.
This however is only for the root view, as you navigate (maybe with a navigation controller) back and forth, that root view's viewWillAppear will get triggered as some point.
In short, if you need to implement something in viewWillAppear in these cases, you should message it yourself when you know it's going to be presented. You can handle this case in your view controller, check out the following article about the matter:
http://www.touchthatfruit.com/viewwillappear-and-viewdidappear-not-being-ca
Good luck.
You should check UITabBarDelegate then look for the method:
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item.
Description: Sent to the delegate when the user selects a tab bar
item.
In some apps that have a tab bar controller, each tab also needs a nav controller before a view can be added:
[[[_mainTabController topViewController] navigationController] pushViewController:renewalScreen animated:YES];
Do you mean 4 tab items on a tab bar, rather than '4 tab bars'? If you have a tab bar with tab items, the viewWillAppear: methods absolutely should be called by the system as the tabs are selected by the user. You could have other issues that are causing the problem.
You didn't forget to call [super viewWillAppear] somewhere?
Try using the viewDidAppear method instead.
I'm trying to write an application that uses a navigation bar and tab bar in what (I'm gathering) is an unusual manner.
Basically, I've got several "pages" ("home", "settings", etc) that each have their own tab. I'd also like to have it so that the "home" page is the root view of the navigation bar, and the other pages are the second-level views of the navigation bar. That is, I should be able to navigate to any page by clicking the appropriate tab bar item, and should be able to navigate to the home page from any other page by clicking the navigation bar's back button.
Currently, I have a UINavigationBar (through a UINavigationController) and a UITabBar (through a UITabController) as children of a UIView. The various pages' view controllers are set as the tab controller's viewControllers property, and the home page's controller is also set as the navigation controller's root view. Each page view's tag is set to its index in the tab control. I have the following logic in the tab controller's didSelectViewController delegate method:
- (void) tabBarController:(UITabBarController*) tabBarController
didSelectViewController:(UIViewController*) viewController
{
if ([navController.viewControllers count] > 1)
[navController popViewControllerAnimated:NO];
[navController pushViewController:viewController animated:YES];
}
Also, in the navigation controller's didShowViewController delegate method, I have the following code:
- (void) navigationController:(UINavigationController *) navigationController
didShowViewController:(UIViewController *)viewController
animated:(BOOL)animated
{
tabController.selectedIndex = viewController.view.tag;
}
The problem that's occurring is that when I run this, the navigation bar, tab bar and home page all display ok, but the tab bar will not respond to input - I cannot select a different tab.
I gather it's more usual to have the tab bar as the child of the navigation control, or vice versa. This doesn't seem to fit my approach, because I don't want to have to individually create the subordinate control each time a change occurs in the parent control - eg: recreate tab bar each time the navigation bar changes.
Does anyone have suggestions as to what's wrong and how to fix it? I'm probably missing something obvious, but whatever it is I can't seem to find it. Thanks!
EDIT: I'm guessing it has something to do with both controller's trying to have ownership of the page controller, but I can't for the life of me figure out a way around it.
Yikes. You're way out on a limb here. I've learned the hard way that UINavigationController and UITabBarController aren't very accommodating when you try to use them in nonstandard ways. UINavigationBar and UITabBar weren't designed to coexist as siblings in the view hierarchy. They really want to be distant cousins. Maybe the approach you're pursuing can be made to work somehow, but I personally wouldn't even attempt it.
With that said, I'll suggest one thing you can check, and then I'll tell you how I'd approach the problem.
Have you implemented, and are you returning YES from tabBarController:shouldSelectViewController: in your UITabBarControllerDelegate? If not, that would prevent your tabs from switching.
Assuming that won't solve all your problems, here's what I would do to get the behavior you're seeking:
Create a UITabBarController and set its view as the root view of your window.
Have a separate UINavigationController under each tab, each with its own navigation bar. (This is the standard way to use UINavigationController and UITabBarController together.)
Set a UITableViewController that displays an identical copy of your main menu table as the root view controller for each navigation controller.
When a row is selected on your "Home" view controller, switch to the associated content tab.
Set a delegate on your UITabBarController. In its tabBarController:didSelectViewController method, call pushViewController:animated:. This is similar to what you're currently doing, except you'll be calling it on (UINavigationController *)tabBarController.selectedViewController.
In the viewDidAppear:animated: of the root view controllers of your content tabs, switch to the "Home" tab. This way, when the user hits the back button to go back to "Home", it will switch to the right tab. (You may also need conditional code to prevent this from happening when the user first selects a content tab. I'm not sure.)
I'll be curious to know if Apple accepts this nonstandard behavior. Come back and let us know. Also, let us know if you get your approach working somehow.