Let's say I have a ViewController that needs access to a view. In the class file of the ViewController I am doing
IBOutlet ViewA *someview;
And in Interface Builder, I drag and drop a UIView in my document and set the class to ViewA.
I am missing how "stuff" is instantiated when you connect through IB. Is ViewA automatically allocated when the .xib files are unarchived? What if I don't want to use IB?
If you don't want to use IB, instead of putting that IBOutlet there, you just eliminate it, leaving just
ViewA *someview;
and then somewhere in your code, when you need the view, you do a
someView = [[UIView alloc] initWithFrame: rect];
I prefer IB, others prefer programmatically creating views. I like how I can position all the views subViews, including UIButtons, UILabels, UITableViews, other UIViews, etc. without having to use coordinates to do so. YMMV.
As to when things get instantiated, when using a XIB, your app will probably lazily load the view controller, and once it is loaded, it will load your view. What actually loads your view, is when you first access the variable someView. While there is an outlet connection, the view and its subViews are not loaded till you access someView, in any manner, for example if you just do a:
if (someview) {
// the view is loaded now
}
Related
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.
Does anyone know a way to, in a storyboard, load a UIView's contents from another nib? I know I can do this easily with code, but I am trying to figure out how to do more in IB.
I have a storyboard with my main UI layout, I have a UIScrollView and I want to design its contents in IB. The only way I could figure out how to do this was to design the UIView in its own .nib, but then my issue is, how do I load the nib without coding it to do so? Is this even possible? It doesn't seem too far fetched to me.
I'm assuming you simply want to lay out your UIScrollView in IB, that a .nib is mentioned because that was an approach you were exploring, but if you could do this strictly in your storyboard that would be acceptable, if not preferable:
First, create a new file in Xcode that is a subclass of UIScrollView.
In your storyboard, drag a UIScrollView out to the scene (viewcontroller) where you want to display this scroll view.
In the Identity inspector, set the Custom Class of the UIScrollView to your subclass of UIScrollView.
Create an outlet for this UIScrollView by ctrl+dragging the UIScrollView into the .h file of the ViewController subclass it's displayed in. Name it something like myScrollView
In your ViewController's -viewDidLoad method, set the contentSize property of the UIScrollView to whatever size you want it to be. So it will look something like:
self.myScrollView.contentSize = CGSizeMake(800,800);
Now, drag out UI objects to your UIScrollView and design.
IMPORTANT: To create outlets to these objects is a little tricky. Let's say you've dragged out a UILabel. You need to manually go into your UIScrollView subclass and add to the .h
#property (nonatomic, weak) IBOutlet UILabel* myLabel;
and to the .m
#synthesize myLabel = _myLabel;
Now you need to get your outline view on screen along with your storyboard and ctrl+drag FROM YOUR SCROLL VIEW TO YOUR LABEL to create an outlet. This is kind of the reverse of what you're used to.
Now you can reference that outlet from within the viewcontroller or the scrollview subclass . For instance, in the viewcontroller -viewDidLoad you could say:
self.scrollView.myLabel.text = #"Hello World";
HTH!
If what you want is to edit inside a scrollview from IB, it's a pain, but doable.
Have a look at my answer on this question.
Add a generic UIView in the IB, setting its custom class to the name of your nib file.
Replace GradientControl with the name of your nib file (minus the '.xib').
Can anyone describe how it is possible to have a TableViewController with its xib file having a at its root and the uitableview as a subview?
I believe the TVController somehow assumes that UITableView will fill the entire area.
Why is that?
I have a really specific need to build a kind of side and bottom tabbed interface with a UITableView as its main area. Pressing tabs changes the predicate for the fetchedresultscontroller etc etc.
The reason I want this is because of the breadth and depth of the data categories in the data model. I rally need to flatten the menu structure a lot...other wise with a table and navbar controller structure, user experience will be akin to sinking to ever deeper depths of a cavern!
My idea is tried and true in other paradigms...in iOS it almost looks like it's Apple's way or the highway. I am OK with APPLE of course no gripe.
But I really would like to create this.
I tried adding a new tableviewcontroller complete with xib and then removing the UITableView in IB and replacing with a UIView and a UITableView as a subview, hooking up (I believe) the delegate to the file's owner.
I created an IV tableView for when I want to reference it and again used IB to hook it up in IB
Try to run it and it whines that...
[UITableViewController loadView] loaded the "TabbedTableController" nib but didn't get a UITableView.'
Really can't seem to get my head around what the issue is here.
There doesn't appear to be anymore I can do to hook the UITableView up!
Any help would be terrific. I'll send you a Christmas card in desperation :^)
Also...why should it be so and how strict is this UITableView fullscreen thing?
Enlighten me if you can. The docs I have read don't want to.
Regards
Keith
A UITableViewController does assume that the root view (i.e. the controller's view property) will be a UITableView, thus the table view fills the screen. When you need a view that combines UITableView with other top level views, you will need to do a little more work but it's not hard:
Your view controller will not subclass UITableView. Instead, do this:
#interface MyViewController : UIViewController
<UITableViewDelegate, UITableViewDataSource>
#property (nonatomic, weak) IBOutlet UITableView* tableView;
In Interface Builder, drop in a UITableView and whatever other controls you need. The table view can be any size and in any location in the view hierarchy. Also in Interface Builder, ctrl-drag from the table view to your VC and set the delegate and dataSource outlets, and ctrl-drag from your VC to the table view to set the tableView outlet.
Your view controller implementation should be the typical table view controller implementation: cellForRowAtIndexPath, etc.
A UITableViewController is more or less just all of the above work packaged up into a single unit for you.
While creating a navigation based application, it automatically creates a root view controller which subclasses UITableViewController, but in MainWindow.xib as you know I can't see a UITableView is placed under root view controller but we drag and drop a table view there. Can we simply drag and drop a UIView instead of a UITableView and change the root view controller class to sublass a uiview instead of UITableView and change its methods?
Or I must drag a UITableView in IB for the root view controller? I am a beginner and I do not want to make complicated things so what is the simplest way of using a UIView as a root. If thats not simple I will stick with the table view.
Yes you can change. You just need to change some bindings in inteface builder and change rootViewController's superclass to UIViewController instead of UITableViewController.
UPDATE
First open the rootViewController.xib and delete the tableiew from there and drag-n-drop a UIView. Bind that View to view property in file-owner. Change superclass of rootViewController from UITableViewController to UIViewController. That's it.
Here are the screenshots.
I've created a ChildViewController class, and then a nib that uses that class.
Then I created a BaseView, that includes some buttons, and some text that I'll be changing programmatically.
Then I created two more views (Boy and Girl), that I want to be able to lay behind the baseview so that the background color is different along with some graphics in an ImageView. I've named the views that I created in IB 'Boy' and 'Girl'...
But when I go back to my code where I'm calling ChildViewController, I'm not sure how to access the views I created so I can call insertSubView. Do I need to instantiate them in code? (in ViewDidLoad perhaps?) Does the nib create the instances when it loads?
I'm confused about how to handle multiple views for a single ViewController
edit =================
#Pablo Santa Cruz
Your answer assumes that i have two nibs and two view controllers (one for each view). I want to know if I can use one nib and one controller, and load in UIViews. It seems silly to create another nib and controller, when all want to do is change the background color and some graphics. Can't I programatically load in UIViews into a UIViewController?
Add IBOutlets in your App Controller class in Xcode then link them in IB (ctrl-click or right-click) from the connections tab in the Inspector to the object.
Then you will be able to send method calls to the objects.
The code in Xcode should look like this:
#interface AppController : NSObject
{
IBOutlet Girl girlIvarName1;
IBOutlet Boy boyIvarName2;
}
#end
You can access a UIView programatically by assigning a value to its tag property, which can be set in IB on the first tab of the inspector (Command 1)
The tag value defaults to zero, so if you want to access it specifically, make it non zero and unique. e.g. 100, which I will use in the example code below
Once the tag is set you can access the view using the following code in your UIViewController that was initWithNibName for the NIB containing the tagged view
UIView *aView = [self.view viewWithTag:100];
You can get instances for your IBuilder views with this piece of code:
boyViewController = [[BoyViewController alloc] initWithNibName:#"BoyViewController" bundle:nil];
girlViewController = [[GirlViewController alloc] initWithNibName:#"GirlViewController" bundle:nil];
Assuming your NIB file names are BoyViewController and GirlViewController. With those instances, you can do whatever you need to. I.E., adding them to a parent view (with addSubView message on the parent).