UIViewController has an ivar (and #property) called view. It is not however, an IBOutlet.
When creating a view nib in Interface Builder, you typically set File's Owner to be your UIViewController (or subclass thereof), and you wire the nib's view to File's Owner's view outlet.
How does this work if the UIViewController view member isn't an IBOutlet?
The IBOutlet keyword is used to indicate that a property should show up in Interface Builder for classes that you write. Interface Builder internally has additional knowledge about system provided classes.
If you are working with Interface Builder on the desktop, rather than iPhone, you can write Interface Builder Plug-Ins to integrate your custom classes into the Interface Builder Library (This is not supported in Interface Builder for the iPhone). In writing a plug-in, the plug-in author provides "class description" files that declare this same actions/outlets information to Interface Builder as one achieves with the IBAction/IBOutlet keywords. You can read more about it in the Interface Builder Plug-In Programming Guide.
It works essentially the same way for system provided classes as it does for plug-ins.
I read this article a while ago and it finally tied it all together for me. Maybe it'll help you?
The simple answer is that Apple wrote both Interface Builder and UIViewController.
The view property of UIViewController is just that, a Property. The whole purpose of a UIViewController is to control a view. The view property allows you to assign that view to an UIViewController. That's the purpose of the view and that's why it shows up in IB. It's a property. Just like textLabel is a property of UILabel.
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I have a custom ViewController which allows selection of an image from a grid. The ViewController uses the AQGrid control and is really just a modified version of the samples shipped with AQGrid.
I'm trying to hook it up in InterfaceBuilder, but documentation on how to do this seems sparse. In standard Cocoa apparently I should create an IB plugin to use with IB, but I'm just looking for the quickest option really as there are a few of these custom ViewControllers which I need to hook up (including a rating control). I've also tried dragging the "Object" controller in IB to my tabpage, but it just gets added to the tree outside of the tabcontroller (see screenshot).
As far as I understand your question, you have to add a generic UIViewController to your nib file and then change its class in the Identity inspector to whatever you need as long as it's a subclass of UIViewController.
Use a "Custom View" object and assign the appropriate class in the inspector's info tab. Using Interface Builder plugins isn't really advisable anymore, because Xcode 4 doesn't support them.
I'm trying to keep things organized and create hierarchy of views for my app.
So for instance I want to create a custom view to display some text, another custom view to display progress and then use all those views in the main view created with View-Based Application template.
I know how to create it programmatically - you create UIView subclass, implement drawRect method, place an empty UIView in Interface Builder and chance it's Class to my custom class. My problem is that I want to create those custom view's in Interface Builder instead programmatically.
So far I've created UIViewController controller with XIB file and in viewDidLoad method of view controller from the template I create that custom view controller instance and add it's view as a subview of that empty UIView added in Interface Builder (the same you would change Class in programmatic approach).
It works, but it's more of a hack for me and it's hard for me to believe that there isn't a better method where I could add those custom views in interface builder without having to implement viewDidLoad method and create controllers and add their views inside of that method.
This was originally a comment in Ratinho's thread, but grew too large.
Although my own experience concurs with everything mentioned here and above, there are some things that might ease your pain, or at least make things feel a little less hack-ish.
Derive all of your custom UIView classes from a common class, say EmbeddableView. Wrap all of the initWithCoder logic in this base class, using the Class identity (or an overloadable method) to determine the NIB to initialize from. This is still a hack, but your at least formalizing the interface rules and hiding the machinery.
Additionally, you could further enhance your Interface Builder experience by using "micro controller" classes that pair with your custom views to handle their delegate/action methods and bridge the gap with the main UIViewController through it's own delegation protocol. All of this can be wired together using connectors within Interface Builder.
The underlying UIViewController only needs to implement enough functionality to satisfy the "micro controller" delegation pattern.
You already have the details for adding the custom views by changing the class name and handling the nib loading. The "micro controllers" (if used) can just be NSObject derived classes added to the NIB as suggested here.
Although I've done all of these steps in isolated cases, I've never taken it all the way to this sort of formal solution, but with some planning it should be fairly reliable and robust.
For this to work, you have to create a plug-in for Interface Builder that uses your custom control's class. As soon as you create and install your plug-in, you will be able to add by drag and drop, instances of your view onto another window or view in Interface Builder. To learn about creating IB Plugins, see the Interface Builder Plug-In Programming Guide and the chapter on creating your own IB Palette controls from Aaron Hillegass's book, Cocoa Programming for Mac OS X.
Here is the link to the original author of the accepted answer to a similar question.
Maybe i didnt understand u?
you have library in the Interface builder u can move every component u want and place it on your view. (u can add another view by adding UIView and change its class name in the 4th tab).
then u declare vars with IBOutlet and connect them from the 2nd tab of ur file's owners to their components...another question?
Unfortunately, you can't do what you want to do with UIKit. IB Plugins only work for OS X, and Apple explicitly doesn't allow them for use with iOS development. Something to do with them not being static libraries. Who knows, they may change this someday, but I wouldn't hold your breath.
If I have a UIScrollView set up in the view via the Interface Builder, how do I get a reference to it in the ViewController implementation? I want to programmatically add labels to the scroll view.
For example, in C# if you have a textbox declared in the UI/form, you can access it by simply using the ID declared for that textbox. It doesn't seem this simple in objective c.
Thanks
Kevin
Assuming I understand you rightly and you are instantiating a view controller from a .xib containing subviews including the UIScrollView you want, there are two ways - first, you can find it in the subviews array that is owned by the view controller. Second, you can add an IBOutlet reference to it in your header file, then in interface builder make the connection using the connections inspector. Then you can refer to the object in your code, change frame, add labels etc.
You need to wire your ViewController up to your Nib files. This is pretty straightforward. This is your basic workflow for using Interface Builder on the iPhone/iPad:
Set the Class of the 'File's Owner' to the class of your view controller. You can do this by selecting the 'File's Owner' object in your nib window, pressing Command-4, and setting the class via the drop-down.
Create properties in your View Controller with the following format:
#property (nonatomic, retain) IBOutlet UIScrollView *scrollView;
The IBOutlet keyword is a macro that evaluates to nothing. So it doesn't actually do anything to your code, it just exists to let Interface Builder know that the 'scrollView' property can be bound to.
Control-drag from the object you'd like to bind to your ViewController. In the popup you can select the property you'd like to bind to the scroll view object.
This sort of stuff is pretty basic Xcode stuff. If you read any tutorial out there it'll cover this. Good luck, and enjoy!
edit:
I should add that if you used the default "New UIViewController Subclass" from the New File dialog, it will have done step one for you. You'll have a nib file and a View Controller that already know about each other.
Yes, the code you wrote is all you need in your header. Just make sure you connect the Scroll View object to the property in Interface Builder.
Yup! 'viewDidLoad' is added after all the connections specified in the Nib file have been made, so you can be confident that scrollView point to the correct object (assuming everything in the Nib is wired correctly, which is an easy mistake to make)
Is there a way to make e.g. UIViewController use a custom UIVIew class?
Yes, there is. Just create your custom class that inherits UIView, open interface builder, open the ViewController xib file, select the view, and change the Class on the View Identity tab.
You can create your custom view in the Interface Builder and reuse it in a Controller. I just found the answer at the bottom of this post:
http://fdiv.net/2011/10/29/reusable-views-ios
Download the example, there is no code in the files, only the connections used in IB and the skeletton of the custom view.
This shouldn't be this confusing. I have a custom UIView with a bunch on controls on it. UILabels, buttons, etc. I've created this Nib using Interface Builder. I want to be able to position this custom uiview on another UIView using the interface builder.
How do I link my UIView custom class, to the nib? initWithCoder gets called, but I want this class to get loaded from the nib.
Thanks
For this to work, you have to create a plug-in for Interface Builder that uses your custom control's class. As soon as you create and install your plug-in, you will be able to add by drag and drop, instances of your view onto another window or view in Interface Builder. To learn about creating IB Plugins, see the Interface Builder Plug-In Programming Guide and the chapter on creating your own IB Palette controls from Aaron Hillegass's book, Cocoa Programming for Mac OS X.
Here is the link to the original author of the accepted answer to a similar question.
You only need to make a plugin if you want the custom view to draw correctly in the nib you are using it. You can make a custom control and then have it show as a blank rectangle until instantiated during run right now.
How do I get a view in Interface Builder to load a custom view in another nib?
You can insert a UIViewController object using Interface Builder, and then set the UIViewController's "Nib name" property.
I don't know if this messes up your model, but I think it's the only way to do what you're trying to do.
In IB bring up the Identity Inspector tool (Command-4) then select your custom view and in the Class pop-up choose the name of your custom class instead of generic UIView. You may want to connect it to an ivar as well. In your ViewController declare an instance of your custom class with an IBOutlet in front of it. Then go back and bring up the Connections Inspector and connect your view to the ivar by click-dragging from the custom-view's referencing outlet to the File's Owner (which should be an instance of your ViewController) and choosing the ivar name.
When your NIB is loaded it should be creating an object of that type and connecting it to that variable.