Dynamically load nib for iPhone/iPad within view controller

Question

I have converted an iPhone application using the wizard like thing in XCode into a universal app.

It builds fine but obviously looks a bit rubbish in some areas :)

I need to load nibs according to which device is being used. I dont wish to create my view controllers using initWithNib as I already have code to create the controllers with some data (initWithMyLovelyData) which doesnt do anything to do with nib loading.

I know to find out the device you use UI_USER_INTERFACE_IDIOM() so I tried overriding the initWithNibName within the actual view controllers themselves, assuming they get called internally somehow. But it's not working as I guess I am unsure of the syntax.

I have tried

if(ipad..) self = [super initWithNibName:@"MyIpadNib" bundle:nibBundleOrNil];

And that doesnt work :/

EDIT - I know I have massively edited this, made my question a bit more specific after doing some more research - apologies!

score 77 · Answer 1 · answered Mar 07 '12 at 15:04

77

Actually, Apple does all this automatically, just name your NIB files:

MyViewController~iphone.xib // iPhone
MyViewController~ipad.xib // iPad

and load your view controller with the smallest amount of code:

[[MyViewController alloc] initWithNibName:nil bundle:nil]; // Apple will take care of everything

answered Mar 07 '12 at 15:04

Adam

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if you use this statement: [MyViewController alloc] init]; in above example instead, is it doing exactly the same thing? or is it doing something slightly different? – hokkuk Mar 09 '12 at 16:24
I expect "init" does nothing. If you want it to load a NIB, you need to call initWithNib - or else manually load a NIB from the bundle – Adam Mar 10 '12 at 14:50
2

[[MyViewController alloc] init] is exactly the same as [[MyViewController alloc] initWithNibName:nil nibBundle:nil] This is mentioned in the UIViewController.h file: "If you subclass UIViewController, you must call the super implementation of this method, even if you aren't using a NIB. (As a convenience, the default init method will do this for you, and specify nil for both of this methods arguments.)" – jsd Jul 25 '12 at 22:00
Where is this documented? The documentation of "nibName" in UIViewController specifies how the nib name is resolved when none is provided, but does not seem to mention this approach. – Jan 19 '13 at 08:51
IIRC this feature is only documented in one place - the bits about "loading resources / using Bundles", which many people never happen to read. Technically, nibName etc re-uses the underlying bundle/resource-loading system - so Apple assumes you'll read this elsewhere and remember it. – Adam Jan 21 '13 at 00:02
2

Just want to add that the bits of the documentation describing how "iOS Supports Device-Specific Resources" can be found here: https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/LoadingResources/Introduction/Introduction.html – Lasse Christiansen Feb 09 '13 at 11:29
This is definitely the better answer. No reason to switch on interface idiom. No reason to copy/paste the init code. No reason to type the nib name twice (or at all). – John Cromartie Feb 15 '13 at 19:34
`initWithNibName:nibBundle` is the designated initializer for `UIViewController`, so even if it wasn't explicitly documented anywhere, you would know that calling `init` on a view controller would eventually call through to `initWithNibName:nibBundle`. – kubi May 09 '13 at 17:26
Apple skipped the designated initializers specifically in UIViewController / UIView since iOS version 2.0. Anything loaded from NIBs used initWithCoder/awakeFromNib combo instead (bypassing their own - documented! - designated init'r). So ... you can't trust "designated initializers" in UIKit, sadly – Adam May 10 '13 at 08:42
In what scenario will name of the xib play a role ? In my case it works regardless of how I name xib file. I guess framework simple relies of value in `customClass` attribute. Is that correct, @Adam? – expert Aug 30 '13 at 01:12

kubi · Accepted Answer · 2014-11-13T20:11:08.253

22

EDIT: @Adam's answer below is the correct answer.

To determine which nib to load, do the following, and scrap your initWithMyLovelyData method and use a property to set the data. You should be able to easily move all your init code into the property setter method.

MyViewController *viewController;

if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
    viewController = [[MyViewController alloc] initWithNibName:@"ipadNIB" bundle:nil];
} else {
    viewController = [[MyViewController alloc] initWithNibName:@"iphoneNIB" bundle:nil];
}

viewController.myLovelyData = someData;

edited Nov 13 '14 at 20:11

answered Jun 16 '10 at 11:02

kubi

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Sorry to dig up old(er) posts but: This is not working for me. Any ideas? – Linuxmint Mar 15 '11 at 00:08
@Linuxmint What problem are you having? – kubi Mar 15 '11 at 09:21
http://stackoverflow.com/questions/5306346/trouble-with-loading-a-separate-xib-for-ipad-or-iphone – Linuxmint Mar 15 '11 at 18:11
5

FWIW, @adam's answer is the correct one and much better than this. – kubi May 09 '13 at 17:22
Since the nib name is just one of two strings, and the rest of the VC allocation/initialization is the same, you can shorten the code by having just one call to alloc/init the VC, using an NSString variable which is either set to one nib name or the other. – Alexander Nov 13 '14 at 02:34

score 2 · Answer 3 · answered Oct 04 '10 at 09:22

I just put these two methods in a class called IPadHelper, and use the addIPadSuffixWhenOnIPad method to conditionally pick between two nibs depending on platform

+ (BOOL)isIPad{
    if (kCFCoreFoundationVersionNumber >= kCFCoreFoundationVersionNumber_iPhoneOS_3_2){
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad){
            return YES;
        }
    }
    return NO;
}

+ (NSString *)addIPadSuffixWhenOnIPad:(NSString *)resourceName{
    if([IPadHelper isIPad]){
        return [resourceName stringByAppendingString:@"-iPad"];
    }
    else {
        return resourceName;
    }   
}

see here http://cocoawithlove.com/2010/07/tips-tricks-for-conditional-ios3-ios32.html for more explanation of the first method...

Compiler said that this is wrong, because Class methods should return objects (id). So If think it will be better to add this to C file. — rowwingman, Jan 17 '12 at 22:10

score 2 · Answer 4 · answered Oct 09 '10 at 07:57

You can have your cake and eat it too. Just add a method that wraps initWithNibName:bundle: and adds your myLovelyData parameter:

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil  myLovelyData:(id)data
{
    if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) 
    {
        // Custom initialization using myLovelyData
        //
    }
    return self;
}

score 0 · Answer 5 · answered Jan 17 '12 at 22:13

I think it will be better to create C file.
FileHelper.h

#import <Foundation/Foundation.h>
BOOL isIPad();
NSString *addIPadSuffixWhenOnIPad(NSString *resourceName);

FileHelper.m

#import "FileHelper.h"
BOOL isIPad() {
    if (kCFCoreFoundationVersionNumber >= kCFCoreFoundationVersionNumber_iPhoneOS_3_2) {
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
            return YES;
        }
    }
    return NO;
}

NSString *addIPadSuffixWhenOnIPad(NSString *resourceName) {
    if(isIPad()) {
        return [resourceName stringByAppendingString:@"-iPad"];
    }
    else {
        return resourceName;
    }   
}

Dynamically load nib for iPhone/iPad within view controller

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