I'm having an annoying problem, that may have a simple answer!
I have a ViewController (which contains a TableView Controller and Header View) which I am pushing on to a Navigation Controller - When I push it on the first time after launching, I get a blank view. When I click the Back button to pop it, it appears fine from then on until I re-launch the app.
Does anyone know an "obvious" reason why this would happen?
BTW- following the code in Debug, it appears to be doing all the correct things.. loading the ViewController variables if nil, etc. before the first view.
Thanks!
did you reload the table after data are loaded ?
[tableView reloadData];
Related
(Apologies for not being able to embed my images yet).
Using iOS storyboards, I have a UITabBarController with a UINavigation Controller/UITableView(1) embedded in it. This UITableView(1) then calls another UITableView(2):
What I'm trying to do is to make UITableView(2) appear when the Tab Bar is changed to that tab, and then have the UINavigationBar left arrow button exist to get back to UITableView(1).
The existing functionality I can think of which does this is the iPhone Mail app, where when you launch it you see your Inbox, and you can hit the left-arrow Mailboxes button to get back to your mail box list.
I've tried attaching the tab bar directly to UITableView(2) but it doesn't work as expected, there's no left arrow back button to get back to the previous view when the app is run.
I've also tried adding a navigation controller to that UITableView(2) and the Navigation controller correctly appears, but still without any back button:
Any suggestions as to what I'm doing wrong would be greatly appreciated, I'm fairly new with storyboards and it's difficult to find what to search to get this working.
If it's not possible with just storyboards themselves, is there some kind of automatic (non-visible) push to the 2nd UITableView I could do?
Thanks!
Nick.
This tutorial will definitely help you : http://maybelost.com/2011/10/tutorial-storyboard-in-xcode-4-2-with-navigation-controller-and-tabbar-controller-part1/
I ended up implementing it the following way, as I wanted to perform the majority of the work within storyboards.
I set up the storyboard with the tab bar embedding the UINavigationController, which contained UITableView(1) which then contained a custom segue to UITableView(2):
Then within the class associated with UITableView(1) I added this single line:
- (void)viewDidLoad {
[self performSegueWithIdentifier:#"campaigns" sender:self];
...
}
On load of the tab, the viewDidLoad of UITableView(1) instantly calls UITableView(2) without any kind of animation, showing the back button to UITableView(1), which is exactly what I wanted.
Thanks to those who responded!
You can implement the delegate method as below.
(void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
In this method you can check for the tabBarController.selectedIndex or viewController object. This ensures the selection of correct tab , then push the controller having table 1, then push the controller having table 2.
I have a navigation controller with a UITableView which when goes to another view when a row is selected. When this loads the breakpoints get hit.
Good so far.
When I hit the back button, the table view appears fine, with data.
However, even though I have breakpoints enabled in the viewcontroller, none get hit like when it originally loaded! But yet, the data loads fine. The only breakpoint that registers now is when I click on a row (didSelectRowAtIndexPath).
Where are the breakpoints set that you are expecting it to break?
Perhaps you need to call the following in the viewWillAppear method...
[self.table reloadData];
It would depend on where your breakpoint is actually located. If you have a breakpoint in viewDidLoad method, then it will only be called once when the view is first created. When you go back from another view, the view is not loaded again. So the breakpoint will not hit. However, viewWillAppear method will be called.
You are using a navigation controller here. Navigation controller holds a navigation stack, which includes UIViews on top of each other, with the visible one on the top.
Now, let's say the table view was loaded, then you move to another (which is now the topmost view in the navigation stack). Note - the table view is not gone. It's there, just under the view you are currently presenting.
Thus, when you move back to the table view, it is not reloaded, because it was never gone (released), just hidden.
There are exceptions to the above, and sometimes a view which is not presented on screen will be released (low memory scenarios situations, for example), but you can't count on it.
The UINavigationController Class Referance explains this concept very well.
I have a two tabbed application. The first tab is a NavigationController that has a few TableViewControllers in it. The second tab is also a NavigationController that has a TableViewController in it.
What I'm trying to achieve is: When someone clicks on a button in the TableView inside first tab, I want to add the the clicked row to the TableView inside the second bar.
I'm already saving the information when it is clicked to NSUserDefaults. When I quit the app and restart, the second bar shows the updated info. But it doesn't show the updated rows if I switch to it while the application is running.
How can I make the second bar reload/update dynamically with the updated rows when someone does sth in the first bar?
I've called [self.navigationController parentViewController] successfully to get the tabBarViewController, which is the highest level, when the the tableview in the first bar changes. How can I get to the TableView inside the NavigatinController inside the second tab from there to have it update itself? Or should I be doing this another way?
Thanks.
i think you can call reloadData in second bar's view controller function
-(void) viewWillAppear:(BOOL)animated
{
[tableView reloadData];
}
You could call the reloadData method on the UITableView within that TableViewController. Honestly, I think you should be using CoreData but I don't know enough of the structure of your data so... try that?
I have viewBased Application, i have 3 view controller in that.
When I want to go back to first view from second view, I want that view to be reloaded from start.
Code I use to dismiss the present view is:
//Back Button Code:
[self dismissModalViewControllerAnimated:YES];
//Code I use to go to new view is:
[self presentModalViewController:secondView animated:YES];
I am not getting what you trying to do...
put your logic inside viewWillAppear method... which gets called everytime view Loads..
When I want to go back to first view from second view, I want that view to be reloaded from start.
Wich one?
Well I think it should work since dismissing a modal dialog unloads it. What happens exactly that you don't want? You must have retained something you don't want to.
It's not clear if you want your first view to restart, or your second view to restart.
Answer for both cases:
If you want view 1 to restart, move the code you need re-executed into viewWillAppear()
If you want view 2 to restart, it's been released from memory so going back to it will call viewDidLoad() and restart it anyway.
Hope that helps....
I have a UIViewController that is pushed onto a UINavigationController and is currently displayed. When I go to start some asynchronous task inside the view controller, I can set hidesBackButton on self.navigationItem to YES, and the back button is hidden correctly.
As soon as the task is finished, and I set hidesBackButton back to NO (on the UI thread, I might add, I've made sure of this), nothing happens. The back button remains hidden.
Has anyone seen this before? What drives me especially crazy is that in my application (the same application), in a different UINavigationController hierarchy, the exact same code works correctly!
Are you calling hidesBackButton = NO from a thread? All UI operations should be done on the main thread, otherwise they won't have any effect.
i have not been able to replicate your problem on my machine. however, i faced a similar issue with tableviews even when i was updating my ui on the main thread. but calling setNeedsDisplay fixed that issue.
Can you try this and see if this works:
[self.navigationController.navigationBar setNeedsDisplay];
I guess this should work, you need to do the same, BUT ON THE NAVIGATIONBAR instead. please let me know if this worked - as i cannot test my solution because i never get this problem :-)
Have you tried forcing the view to refresh by calling setNeedsDisplay?
Maybe the OS is not picking up the changes instantly and you need to force it.
Have you tried using the setHidesBackButton:animated: method instead? Perhaps that has a slightly different behavior.
In my case I simply had to give a title to the view, as in:
self.navigationItem.title = #"Menu";
Marinus
I have had a similar issue recently. I tried literally everything I found in SO and other forums- nothing worked.
In my case there was a modally shown UINavigationController with a simple root controller which would push one of two view controllers (A and B) on top of the controller stack when the button A or B was pressed, respectively. Controller B was the one which was not supposed to show the back button. But still, sometimes it did, sometimes it didn't.
After hours of debugging, I managed to track it down. Controller A was a UITableViewController. Each time I selected a cell in this controller, the delegate would pop Controller A off the stack. BUT. I made use of a UISearchDisplayController as well. Turned out that popping the view while the search controller was still active messed up something in the navigation controller that made it impossible to hide the back button in Controller B afterwards (well, it eventually stayed hidden between viewDidLoad and viewDidAppear: but then it always turned visible).
So the solution (rather workaround) was adding this line to where Controller A was dismissed:
controllerA.searchDisplayController.active = NO;
// ...
// [self.navigationController popViewControllerAnimated:YES];
Hope this spares someone a couple of hours.