I have in an app a viewController without a .xib, because I want to use with that ViewController a storyboard instead. The problem is that I don't know how to tell Xcode that ViewController2.storyboard is the view of ViewController2.h and ViewController2.m. Anyone knows it?
When you use storyboards, you generally instantiate the view controller inside the storyboard. The big advantage that storyboards have over .xibs is that they model not just the view hierarchy but also the flow from one view controller to the next. So, you'll probably want to either instantiate your view controller in the storyboard where you plan to use it, or else just go back to loading the view from a .xib (which isn't all that different anyway).
Related
What would be main difference between using instantiateViewControllerWithIdentifier and performSegueWithIdentifier ?
I think that performSegue.. is used for normal pushing of viewControllers as instantiateViewController is used for some kind of modal showing of viewController and then dismissing it when used.
Since there are also modal and custom push in storyboard I'm not sure about my theory so if anyone could explain when to use which one ?
Thanks.
The difference is that performSegueWithIdentifier is used to transition to a specific view controller that is connected by a segue in interface builder (Transition1 in my screenshot).
instantiateViewControllerWithIdentifier can be used to instantiate any view controller on a storyboard, regardless if it's connected by a segue or not (Transition2 in my screenshot).
Push, modal, or any other custom transition could be used for either scenario.
instantiateViewControllerWithIdentifier can also be used to instantiate view controllers from separate storyboard files. A segue has to be within the same storyboard file.
The segue identifier used in performSegueWithIdentifier needs to be set in interface builder.
The view controller identifier used in instantiateViewControllerWithIdentifier is the Storyboard ID field in interface builder.
I've made a view in my storyboard which I've now decided I'd rather display its data via static table cells.
I can't use static table views in a UIViewController (Static table views are only valid when embedded in UITableViewController instances). So, I need to convert my existing UIViewController to a UITableViewController somehow. I've changed the .h file's parent, but that hasn't done it.
Is there another way to get this going? I'd really rather not have to make a new VC in the storyboard and move everything over, it's a big hassle.
I'll add to this, since the question is about how to change a UIViewController into a UITableViewController, and given that this question is over a year old and the original answer, while valid and may or may not have been the only solution at the time, doesn't actually answer the question and is not the only solution.
It IS possible to do this, you just have to set up the table view delegate and datasource outlets in IB, and manually edit the storyboard XML, which sounds scary but is actually very easy.
First, change your class's parent to be a UITableViewController. UITableViewController already adopts the UITableViewDatasource and UITableViewDelegate protocols, so if your class does too you can remove them:
#implementation MyTableViewController : UITableViewController
...
#end
Next, create new referencing outlets on your UITableView for its dataSource and delegate. The easiest way to do this is to control-drag from the UITableView to itself. The popup will give you the dataSource and delegate options.
Lastly, you need to change the storyboard XML. The storyboard file can get pretty big pretty fast. The easiest way to find the scene you are looking for is by setting Storyboard Identifier in the Identity Inspector. To view the XML directly, right click on the storyboard file in the project navigator and select "Open As -> Source Code". Now just search for whatever you set the reuse identifier to earlier. You'll see something similar to this:
<!-- My Table View Controller -->
<scene sceneID="EuE-XX-cCb">
<objects>
<viewController storyboardIdentifier="MY_TABLE_VIEW_IDENTIFIER" ... >
// Lots of other stuff
</viewController>
</objects>
</scene>
All you need to do is change the opening and closing view controller tags
<viewController>
</viewController>
to be tableViewController instead
<tableViewController>
</tableViewController>
That's it! No need to create a new UITableViewController scene or embed a UITableViewController in a container view.
EDIT:
I should also add that the UITableView MUST be the root view. It cannot be embedded inside another UIView.
If you want your static cell table view not to take up the entire screen, then using a container view is the easiest way to go. Start with a regular UIViewController and drag a container view (next to normal UIView in the object list) into its view. Resize it however you want -- the storyboard will automatically provide a view controller connected to this container view with an embed segue. Delete that controller, drag out a table view controller and right-drag from the container view to this table view controller to make a new embed segue. This table view controller can be accessed from the UIViewController with its childViewControllers property (and conversely, you can access the UIViewController from the table view controller with parentViewController if you need to).
What I did, is creating a UITableViewController in IB, open the Storyboard with a text editor, and copy all the nodes inside from the UIViewController to the UITableViewController.
I think that with this way there's less risk of deleting something important.
Before copying the sections objects, make sure that both tableviews (UIViewController and UITableViewController) have the same properties set like: static or dynamic cells, style (plain or grouped), etc.
I decided to give the use of storyboards a go in my current iPhone app. I am facing a bit of a problem. I really need to reuse my UIViewController instances.
What do I mean by that? Well, for example I have a table view controller. When I tap a cell, another view controller is loaded from the storyboard and pushed onto the navigation controller stack. This all works well, but it takes about half a second to a second each time this view controller is loaded. Before I was using story boards I simply solved this problem by caching the created instance so the second time you tap a cell the view controller can be immediately shown.
By caching the created instance I mean something like this:
if (!cachedInstance) {
cachedInstance = [MyViewController new];
}
[self.navigationController pushViewController:cachedInstance];
Does anyone know how to accomplish this using the storyboard? Thanks in advance.
If you are using segues, you will need to create custom segues in order to use a cached view controller like you did before. Otherwise, the typical "push" segue will create a new instance of the view controller for segue.destinationViewController. If you write a custom UIStoryboardSegue class and use custom segues you can override initWithIdentifier:source:destination: and put your cached view controller in for the destinationViewController, and then override perform to use the classic pushViewController call.
That is how you handle the segue if you are really intent on using them. I would just skip it though, unless you really want the fancy arrows to lay everything out on your storyboard. If you skip it you can just instantiate the view controllers into the cache and then push them on just like you did before.
If your question is more about locating a view controller inside a storyboard then you can use:
UIViewController *vc = [[UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil] instantiateViewControllerWithIdentifier:#"Some View Controller"];
Then you can save that to your cache and push it like you did in your example code.
Hope that helps.
So I have a viewControllerA, and I want to add another View managed by viewControllerB to it. There is only one UISlider activating a simple action in viewControllerB. It won't crash if I don't touch this UISlider, it will once I use UISlider. I am using ARC. I am using:
[self.view addSubView: viewControllerB.view];
to add viewControllerB to viewControllerA. Am I missing something? Thanks.
OK. It looks like a really simple situation. I just added one view controller and one action. Here is the demo project code on github: https://github.com/randomor/Demo
The reason why I want this to work is because I have another app that will create a view controller on the spot and add it to anther view. And I don't want to do it modally, because I don't want the new view controller to cover the whole screen. Thanks.
SOLUTION: So I'm now just using the latest ViewController containment API:
[self addChildViewController:viewControllerB];
It works! as long as I added this line, the event will be passed to its own controller and it stopped crashing.
i recommend you, to use the following code
in ViewControllerA.h
#import "ViewControllerB.h"
in ViewControllerA.m (where you want to push the new controller)
ViewControllerB *newController = [[ViewControllerB alloc]init];
[self presentModalViewController:newController animated:YES];
in ViewControllerB.m you will need
[self.presentingViewController dismissModalViewControllerAnimated:YES];
to make it vanish again.
concerning multiple controllers for one open screen (Apple ViewController Programming Guide):
Each custom view controller object you create is responsible for managing exactly
one screen’s worth of content. The one-to-one correspondence between a view controller
and a screen is a very important consideration in the design of your application.
You should not use multiple custom view controllers to manage different portions
of the same screen. Similarly, you should not use a single custom view controller
object to manage multiple screens worth of content.
You should try and avoid the practice of nesting UIViewControllers. While it is technically supported in iOS5, it is ill-advised, for many reasons, including the type of problem that you're having (you have a dangling pointer to a UIViewController, which is why you are crashing).
http://blog.carbonfive.com/2011/03/09/abusing-uiviewcontrollers/
Although this question is extremely vague, I imagine that you are not keeping a reference to View Controller B, and so when view B tries to interact with it, it causes EXC_BAD_ACCESS.
What's the object that is set as the target for the slider? If it's a EXC_BAD_ADDRESS, then you may not be retaining the target, most probably the view controller for the slider.
my iPad app starts with a normal UIView showing a login. After the user logged in the screen is supposed to switch to a split view.
XCode's SplitViewTemplate (and all examples on the web I found) however, place UISplitViewController in the main window's xib and define an outlet in the app delegate.
I find that unlogical in my case because I don't need the controller at startup and would like to (following Apple's guidelines) place the split view controller in its own XIB.
Has anybody a working example or a small step by step instruction? I always end up with the XIB not being loaded.
Or is it just NOT possible? But why would it not?
René
You can put a UISplitViewController into a different XIB. You cannot have it be the owner, but you can have your app's delegate be the owner and load it when it removes the login view.
Add UISplitViewController IBOutlet to app delegate
Create a new, empty XIB for iPad
Set the File's Owner to your app delegate class
Add a UISplitViewController, connect to outlet in delegate
Add views to split vew controller
Then, you just have to handle your login in the app delegate, load the new XIB, and display it.
maybe not the answer to your question but I have in my App also a login window. What I do is to put the login view above - in my case - TabBar.
I found this post. Best way to switch between UISplitViewController and other view controllers?
It seems it really is not supposed to work. You have to put it in the main xib and then apply tricks...