I have a fairly hefty project, where I am loading a few view controllers, one after the other. First, a splash screen, followed by a menu system, and when the user clicks on the menu it goes through to an article view controller.
Putting all these in with shouldAutorotate... set to YES for all rotations, this works fine. However, I have a menu bar I need to slide down over the top when a tap gesture has been recognised. I have one for the main menu, and one for the article view.
If I put one of these in, it still auto-rotates fine. However, as soon as I put the next one in, the auto-rotate stops working. I've tried putting the menu bars in the app delegate, as well as nesting them inside the menu/article view controllers. The Menu Bar view controller also has shouldAutorotate... set to YES. In fact, every single view controller in the project (all 7 of them) have it set to YES. And yet, when I add my second Menu bar controller, it stops auto-rotating. It doesn't even trigger the "shouldAutorotate" method to ask it.
The code is way too large to post here, but if you'd like to see anything in particular then just ask. I'm totally stumped! I'm about to pull the menu bars out of their view controller and code them up in each of the view controllers individually. This will be a hideous amount of code duplication, but I can't think of any other way round it!
Any ideas? Thanks!
The answer appears to be... Don't put view controllers within other view controllers! One view controller = one screen, seems to be the rule. I have a lot to learn!
Related
I made an app for my wife to track inventory. it has a couple of view controllers to enter a new item, display all items, search items, and display selected item. After switching through each view a couple of times (no particular order) all of the textfields become disabled (you cannot select them to change the value) across ALL of the view controllers. The buttons still work however. I have it setup so that when the user enters info into a particular cell, it saves it into memory so that if they switch views and then come back, the cells will get the data in the viewdidload method. Please Help!
*edit - I am using storyboard with a bunch of segues (i'm new to programming and self taught, so idk if this is the right way or not)... here is a pic of my storyboard
http://i.imgur.com/aT3PR0i.png
Ok, with a look at your storyboard, I think I see your problem. If your storyboard looks like somebody spilled spaghetti on it, it's not designed correctly. Specifically, it looks like you're going "backwards" (to controllers you've already been to) using segues -- that's not good. SEGUES ALWAYS INSTANTIATE NEW CONTROLLERS! So, if you go around in a circle a few times, you're adding more and more controllers to your project. To go backwards using segues, you need to use an unwind segue -- it's the only one that is an exception to the rule that segues always instantiate new controllers. The other ways to go backwards, without segues, are popping with navigation controllers, and dismissing modal controllers.
I can't really diagnose your immediate problem without a lot more information, but redesigning the storyboard using unwind segues would probably fix your problem.
It seems like this should be easy to figure out, but I haven't had any luck this afternoon. I threw together this quick, simplified storyboard mockup of my problem.
Basically, I would like the table view controllers below to also be in a tab bar controller (in addition to the already present navigation controller). The tabs would switch between the two table view controllers.
Right now, the view controller with the buttons acts as a sort of menu. Each button leads to one of the table view controllers. Ideally this view controller would not have the tab bar visible, and would only be reachable from back buttons on the nav bars of the table view controllers.
I've tried a few different ways of embedding into a tabbarcontrollers but none of them produce the desired result:
-I've tried selecting both table view controllers and embedding those in a tab view controller. The tabbar doesnt show up in simulator, and the 'unreachable scene' warning appears.
-I've tried embedding the initial nav controller into a tabbarcontroller. This creates a tab entry for the first 'menu' page. It also causes issues with push segues once I connect the tableviews to the tabview.
I would be fine implementing some programmatic options on top of the storyboard, I just chose storyboarding for this project since it's a relatively simple presentation of data.
What is the proper way of going about this? Thanks!
A tab bar controller needs to be the root view controller of your view hierarchy. It goes against the HIG and Apple's standards to put a tab bar controller inside of any other type of container controller.
From the Apple docs:
When deploying a tab bar interface, you must install this view as the
root of your window. Unlike other view controllers, a tab bar
interface should never be installed as a child of another view
controller.
So, the bottom line here is you need to rethink your design. One option would be to set the UITabBarController as the root view of your window, and then have each of your UITableViewControllers inside of a UINavigationController, which is placed inside of the UITabBarController. In this way, you still get the navigation bar, and stay within Apple's design guidelines (you also won't get those pesky warnings, and Apple may even be throwing an exception nowadays if you try to install a UITabBarController as anything other than the root view of the window).
I accept JMStone answer but we might get into situation where we need to put tab bar controller inside other controller especially table view controller.
Please refer Storyboard navigation controller and tab bar controller
and also the good example by Matthjin: http://cl.ly/VQLa
Hopes it help some one who want to put tab bar controller inside table view controller and wants proper navigation.
I've set up a really simple project using storyboards including two views as shown here: http://i.stack.imgur.com/iRx21.png. The navigation can be done by either selecting a cell in the custom table view or hitting the back button labelled with "<<". Everything works fine except the following:
when I switch between the views, every time an instantiation happens. The profiling shows an increasing number of view objects. I would like to keep only one of each view and instantiation should be happen only once. What am I doing wrong? (I'm using ARC.)
Thanks in advance!
You should not link your back button to the parent view controller. This is what causes the new instantiation.
The way to go is to embed the table view into UINavigationController (in IB, choose Editor -> Imbed In -> Navigation Controller. Then change your segue to a Push segue. You can of course hide the navigation bar etc. to make things look exactly as you like. Then, link the back button to the controller with an IBAction and in the handler do a simple
[self.navigationController popViewControllerAnimated:YES];
This would be the appropriate logic of what you are doing. Of course, you can also push the web view modally and then handle the button click with
[self dismissModalViewControllerAnimated:YES];
Just as a disclaimer, I am an iOS beginner, in a pretty unique position. I'm an intern learning on the job, with a hard deadline for a test app, with specific specs. So I unfortunately don't have the luxury of learning all that I should about xCode and objective C.
Anyways, I am trying to create a navigation menu similar to the iPad's slide out menu. I've looked at plenty of sample code given in response to questions like this in the past. It all works perfectly fine, but I can't understand all of what they're doing. I think this results from being fairly bewildered by view controllers and delegates. And, since I'm supposed to be writing this all by myself, I can't just build off of their existing code.
My plan for this working is to have one main view controller, containing the navigation menu in a table view. This is hidden behind a normal UIView, until a button is pressed, at which point the normal UIView slides offscreen enough to reveal the menu. Upon selection of a menu item, the normal UIView would slide back to its original position, and be replaced by the relevant UIView, controlled by its view controller. In other words, clicking on the menu item relating to "Home" would load the homeViewController.xib, controlled by the homeViewController. This would be loaded in that normal UIView subview, on top of the tableView.
I'm able to load a view in that normal UIView as a result of a button press.
homeViewController *_homeViewController = [[homeViewController alloc]initWithNibName:#"homeViewController"];
[self frontView] = _homeViewController.view;
There may be some syntax errors in that code, since its from memory. I'm not able to access the computer with my code on it at the moment, but that's the general gist. Basically, that places the home view nib on the frontView (that normal UIView that's over the table view), but its not connected to homeViewController. Or at least I think that's the issue, when I press a button, that's correctly connected between the nib and the homeViewController.h, and only set to NSLog in the .m file, the application crashes.
Any idea how to connect this nib to its viewController when displayed in this way? Or, to create the nib in IB, without the associated .h and .m files, and use the main view controller as the homeViewController as well? Or, if my logic is inherently flawed, what SHOULD I do? Something with NavigationControllers?
EDIT:
I also tried a new approach- changing homeViewController's file owner to viewController, and connecting the button on homeViewController's action to viewController. This too caused a crash upon pressing the button. I really think the issue is with having multiple view controllers acting on screen at once, or having multiple views from separate nibs, controlled by one view controller on screen at once.
I suspect that your immediate problem is that _homeViewController is being freed as soon as you leave whatever method that code is in. To fix this, create a strong property in this class that holds the _homeViewController for as long as its view is needed and allocate it to that property rather than a local variable. That way, buttons (or whatever) that are part of that view still have a valid controller object backing them.
In the long run, pushing or presenting view controllers when you need the screen to change is a much better strategy but, as I said, the immediate problem.... :)
I have a series of UIViewControllers throughout my application. Most of them have the navigation bar but some of them hide it.
The problem is that sometimes as you transition between a view with or without navbars to another view with or without navbars there is a black box that replaces the navbar during the transition. This problem was discussed here: Hiding a UINavigationController's UIToolbar during viewWillDisappear:
This solution is fine and it does get rid of the black box, but I really don't want what was described as a "Cheshire Cat" disappearance. I've tried myriad solutions using prepareForSegue, ViewWillAppear, viewWillDisappear, etc. The best I can do is change the scenario in which the black bar shows up.
By this I mean, there are four combinations of view transitions between the two navigation bar states (hidden vs. not-hidden):
Hidden - Hidden
Hidden - Not Hidden
Not Hidden - Hidden
Not Hidden - Not Hidden
No matter what solution I've tried, at least one of those combinations results in my black box rearing its ugly head. The problem I have is that I've been unable to find anywhere that I can get a reference to the source view controller and the destination view controller when popping a view off of the navigation controller's view stack.
If I could get both references in the same event, I could simply determine what the combination is and handle the behavior appropriately like I would in prepare for segue.
Now, I know that "it's not possible" is a reasonable (and even a probable) answer, but I won't accept that as a solution alone. If it is indeed not possible, I'd like thoughts on a reasonable alternative. For example, I could handle all view controller popping manually (including the default back button) and thus could get the "upcoming controller" from the navigation controller's stack.
I would just prefer a solution using built in APIs or at least a solution where my controllers didn't have to be aware of their own navigation bar states.
Thanks a lot,
Patrick
I think UINavigationControllerDelegate is what you're after. It declares two methods:
-navigationController:willShowViewController:animated:
-navigationController:didShowViewController:animated:
All you need to do is set yourself as the delegate of the parent navigation controller and implement these methods to be notified of incoming view controllers.
Having said that, I've never needed to resort to this for hiding and showing navigation bars. Strictly speaking, view controllers where the navigation bar will always be visible never touch the navigation bar's visibility. When I'm moving into a view controller where it needs to hide, that view controller is responsible for hiding and setting it back to its prior state before disappearing. Following these standards has proven reliable for me.