I'm trying to do something a bit elaborate but that should be possible, so here is a challenge for all you experts out there (this forum is pack of the lot of you :) ).
Im creating a Questionnaire "component" I want to load on a NavigationContoller my QuestionManagerViewController. This is an "empty" view controller that can load different views depending on the question that needs to be answered.
The way I'm doing this is:
- Create the Question1View object a as UIView subclass, defining some IBOutlets.
- Create (using Interface Builder) the Question1View.xib (HERE IS WHERE MY PROBLEM PROBABLY ARE). I set the both the ViewController and the View to be of class Question1View.
- I link the outlets with the view's component (using IB).
-
I override the initWithNib of my QuestionManagerViewController to look like this:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (self = [super initWithNibName:@"Question1View" bundle:nibBundleOrNil]) {
// Custom initialization
}
return self;
}
When I run the code Im getting this error:
2009-05-14 15:05:37.152 iMobiDines[17148:20b] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UIViewController _loadViewFromNibNamed:bundle:]loaded the "Question1View" nib but the view outlet was not set.'
Im sure there is a way to load the view using the nib file, without needing to create a viewController class.
Any ideas?
Thanks!
Gonso
Source: Tips4all
There is also an easier way to access the view instead of dealing with the nib as an array.
ReplyDelete1) Create a custom View subclass with any outlets that you want to have access to later. --MyView
2) in the UIViewController that you want to load and handle the nib, create an IBOutlet property that will hold the loaded nib's view, for instance
in MyViewController (a UIViewController subclass)
@property (nonatomic, retain) IBOutlet UIView *myViewFromNib;
(dont forget to synthesize it and release it in your .m file)
3) open your nib (we'll call it 'myViewNib.xib') in IB, set you file's Owner to MyViewController
4) now connect your file's Owner outlet myViewFromNib to the main view in the nib.
5) Now in MyViewController, write the following line:
[[NSBundle mainBundle] loadNibNamed:@"myViewNib" owner:self options:nil];
Now as soon as you do that, calling your property "self.myViewFromNib" will give you access to the view from your nib!
Thank you all.
ReplyDeleteI did find a way to do what I wanted.
Create your UIView with the IBOutlets you need.
Create the xib in IB, design it to you liking and link it like this: The File's Owner is of class UIViewController (No custom subclass, but the "real" one). The File Owner's view is connected to the main view and its class is declared as the one from step 1).
Connect your controls with the IBOutltes.
The DynamicViewController can run its logic to decide what view/xib to load. Once its made the decission, in the loadView method put something like this:
NSArray* nibViews = [[NSBundle mainBundle] loadNibNamed:@"QPickOneView"
owner:self
options:nil];
QPickOneView* myView = [ nibViews objectAtIndex: 1];
myView.question = question;
That's it!
The main bundle's loadNibNamed method will take care of initializing the view and create the connections.
Now the ViewController can display a view or another depending on the data in memory, and the "parent" screen doesn't need to be bother with this logic.
Gonso
I'm not sure what some of the answers are talking about, but I need to put this answer here for when I search in Google next time. Keywords: "How to load a UIView from a nib" or "How to load a UIView from an NSBundle."
ReplyDeleteHere's the code almost 100% straight up from the Apress Beginning iPhone 3 book (page 247, "Using The New Table View Cell"):
- (void)viewDidLoad {
[super viewDidLoad];
NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:@"Blah"
owner:self options:nil];
Blah *blah;
for (id object in bundle) {
if ([object isKindOfClass:[Blah class]])
blah = (Blah *)object;
}
[self.view addSubview: blah];
}
This supposes you have a UIView subclass called Blah, a nib called Blah which contains a UIView which has its class set to Blah.
You should not be setting the class of your view controller to be a subclass of UIView in Interface Builder. That is most definitely at least part of your problem. Leave that as either UIViewController, some subclass of it, or some other custom class you have.
ReplyDeleteAs for loading only a view from a xib, I was under the assumption that you had to have some sort of view controller (even if it doesn't extend UIViewController, which may be too heavyweight for your needs) set as the File's Owner in Interface Builder if you want to use it to define your interface. I did a little research to confirm this as well. This is because otherwise there would be no way to access any of the interface elements in the UIView, nor would there be a way to have your own methods in code be triggered by events.
If you use a UIViewController as your File's Owner for your views, you can just use initWithNibName:bundle: to load it and get the view controller object back. In IB, make sure you set the view outlet to the view with your interface in the xib. If you use some other type of object as your File's Owner, you'll need to use NSBundle's loadNibNamed:owner:options: method to load the nib, passing an instance of File's Owner to the method. All its properties will be set properly according to the outlets you define in IB.
I too wanted to do something similar, this is what I found:
ReplyDelete(SDK 3.1.3)
I have a view controller A (itself owned by a Nav controller) which loads VC B on a button press:
In AViewController.m
BViewController *bController = [[BViewController alloc] initWithNibName:@"Bnib" bundle:nil];
[self.navigationController pushViewController:bController animated:YES];
[bController release];
Now VC B has its interface from Bnib, but when a button is pressed, I want to go to an 'edit mode' which has a separate UI from a different nib, but I don't want a new VC for the edit mode, I want the new nib to be associated with my existing B VC.
So, in BViewController.m (in button press method)
NSArray *nibObjects = [[NSBundle mainBundle] loadNibNamed:@"EditMode" owner:self options:nil];
UIView *theEditView = [nibObjects objectAtIndex:0];
self.editView = theEditView;
[self.view addSubview:theEditView];
Then on another button press (to exit edit mode):
[editView removeFromSuperview];
and I'm back to my original Bnib.
This works fine, but note my EditMode.nib has only 1 top level obj in it, a UIView obj.
It doesn't matter whether the File's Owner in this nib is set as BViewController or the default NSObject, BUT make sure the View Outlet in the File's Owner is NOT set to anything.
If it is, then I get a exc_bad_access crash and xcode proceeds to load 6677 stack frames
showing an internal UIView method repeatedly called... so looks like an infinite loop.
(The View Outlet IS set in my original Bnib however)
Hope this helps.
This is a great question (+1) and the answers were almost helpful ;) Sorry guys, but I had a heck of a time slogging through this, though both Gonso & AVeryDev gave good hints. Hopefully, this answer will help others.
ReplyDeleteMyVC is the view controller holding all this stuff.
MySubview is the view that we want to load from a xib
In MyVC.xib, create a view of type MySubView that is the right size & shape & positioned where you want it.
In MyVC.h, have
IBOutlet MySubview *mySubView
// ...
@property (nonatomic, retain) MySubview *mySubview;
In MyVC.m, @synthesize mySubView; and don't forget to release it in dealloc.
In MySubview.h, have an outlet/property for UIView *view (may be unnecessary, but worked for me.) Synthesize & release it in .m
In MySubview.xib
set file owner type to MySubview, and link the view property to your view.
Lay out all the bits & connect to the IBOutlet's as desired
Back in MyVC.m, have
NSArray *xibviews = [[NSBundle mainBundle] loadNibNamed: @"MySubview" owner: mySubview options: NULL];
MySubview *msView = [xibviews objectAtIndex: 0];
msView.frame = mySubview.frame;
UIView *oldView = mySubview;
// Too simple: [self.view insertSubview: msView aboveSubview: mySubview];
[[mySubview superview] insertSubview: msView aboveSubview: mySubview]; // allows nesting
self.mySubview = msView;
[oldCBView removeFromSuperview];
The tricky bit for me was: the hints in the other answers loaded my view from the xib, but did NOT replace the view in MyVC (duh!) -- I had to swap that out on my own.
Also, to get access to mySubview's methods, the view property in the .xib file must be set to MySubview. Otherwise, it comes back as a plain-old UIView.
If there's a way to load mySubview directly from its own xib, that'd rock, but this got me where I needed to be.
The previous answer does not take into account a change in the NIB (XIB) structure that occurred between 2.0 and 2.1 of the iPhone SDK. User contents now start at index 0 instead of 1.
ReplyDeleteYou can use the 2.1 macro which is valid for all version 2.1 and above (that's two underscores before IPHONE:
// Cited from previous example
NSArray* nibViews = [[NSBundle mainBundle] loadNibNamed:@"QPickOneView" owner:self options:nil];
int startIndex;
#ifdef __IPHONE_2_1
startIndex = 0;
#else
startIndex = 1;
#endif
QPickOneView* myView = [ nibViews objectAtIndex: startIndex];
myView.question = question;
We use a technique similar to this for most of our applications.
Barney
I found this blog posting by Aaron Hillegass (author, instructor, Cocoa ninja) to be very enlightening. Even if you don't adopt his modified approach to loading NIB files through a designated initializer you will probably at least get a better understanding of the process that's going on. I've been using this method lately to great success!
ReplyDeleteYou can also use UIViewController's initWithNibName instead of loadNibNamed. It is simpler, I find.
ReplyDeleteUIViewController *aViewController = [[UIViewController alloc] initWithNibName:@"MySubView" bundle:nil];
[self.subview addSubview:aViewController.view];
[aViewController release]; // release the VC
Now you just have to create MySubView.xib and MySubView.h/m. In MySubView.xib set the File's Owner class to UIViewController and view class to MySubView.
You can position and size of the subview using the parent xib file.
I had reason to do the same thing (programmatically loading a view from a XIB file), but I needed to do this entirely from the context of a subclass of a subclass of a UIView (i.e. without involving the view controller in any way). To do this I created this utility method:
ReplyDelete+ (id) initWithNibName:(NSString *)nibName withSelf:(id)myself {
NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:nibName
owner:myself options:nil];
for (id object in bundle) {
if ([object isKindOfClass:[myself class]]) {
return object;
}
}
return nil;
}
Then I call it from my subclass' initWithFrame method like so:
- (id)initWithFrame:(CGRect)frame {
self = [Utilities initWithNibName:@"XIB1" withSelf:self];
if (self) {
// Initialization code.
}
return self;
}
Posted for general interest; if anyone sees any problems without doing it this way, please let me know.
This is something that ought to be easier. I ended up extending UIViewController and adding a loadNib:inPlaceholder: selector. Now I can say
ReplyDeleteself.mySubview = (MyView *)[self loadNib:@"MyView" inPlaceholder:mySubview];
Here's the code for the category (it does the same rigamarole as described by Gonso):
@interface UIViewController (nibSubviews)
- (UIView *)viewFromNib:(NSString *)nibName;
- (UIView *)loadNib:(NSString *)nibName inPlaceholder:(UIView *)placeholder;
@end
@implementation UIViewController (nibSubviews)
- (UIView *)viewFromNib:(NSString *)nibName
{
NSArray *xib = [[NSBundle mainBundle] loadNibNamed:nibName owner:self options:nil];
for (id view in xib) { // have to iterate; index varies
if ([view isKindOfClass:[UIView class]]) return view;
}
return nil;
}
- (UIView *)loadNib:(NSString *)nibName inPlaceholder:(UIView *)placeholder
{
UIView *nibView = [self viewFromNib:nibName];
[nibView setFrame:placeholder.frame];
[self.view insertSubview:nibView aboveSubview:placeholder];
[placeholder removeFromSuperview];
return nibView;
}
@end
None of the answers explain how to create the stand alone XIB that is the root of this question. There is no XCode 4 option to "Create New XIB File".
ReplyDeleteTo do this
1) Choose "New File..."
2) Choose the "User Interface" category under the iOS section
3) Choose the "View" item
4) You will then be prompted to choose an iPhone or iPad format
This may seem simple but it can save you a few minutes poking around for it since the word "XIB" does not appear anywhere.
@AVeryDev
ReplyDelete6) To attach the loaded view to your view controller's view:
[self.view addSubview:myViewFromNib];
Presumably, it is necessary to remove it from the view to avoid memory leaks.
To clarify: the view controller has several IBOutlets, some of which are connected to items in the original nib file (as usual), and some are connected to items in the loaded nib. Both nib's have the same owner class. The loaded view overlays the original one.
Hint: set the opacity of the main view in the loaded nib to zero, then it won't obscure the items from the original nib.
This technique does not work for me. I want to reuse my views in IB so I need to be able to init the view from inside its self. The only way to do this is to do the following
ReplyDelete- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
if (nibNameOrNil)
{
if (!nibBundleOrNil)
{
nibBundleOrNil = [NSBundle mainBundle];
}
NSArray* bundle = [nibBundleOrNil loadNibNamed:nibNameOrNil owner:self options:nil];
for (NSObject* object in bundle)
{
if ([object isKindOfClass:[UIView class]])
{
__contentView = (UIView*)[object retain];
__contentView.frame = self.bounds;
[self addSubview:__contentView];
}
}
self.backgroundColor = [UIColor clearColor];
}
return self;
}
I need a better solution then releasing the view object every time i init it.