Objective-C: Instance Method is Never Called

Question

Hi,

I've got a class called RootViewController with this:

Test *myLevelObject = [[Test alloc] init];
[myLevelObject afficher];

It is supposed to call my method -[ Test afficher] but there is no warning or error and it does enter the method. Any ideas? thx

Declaration of test class :

test.m :

#import "Test.h"
#import "RootViewController.h"

test.h :

#import <UIKit/UIKit.h>
@class RootViewController;
@interface Test : UIViewController <UIActionSheetDelegate,UITextFieldDelegate>{




-(void) afficher{



   NSLog(@"hello");
   poids.text = [NSString stringWithFormat:@"lol"];
   labelalco.text = [NSString stringWithFormat:@"cac"];

}

it show in console "hello" but it doesnt execute my 2 line of code.

ok now i tryed to do UIAlertView and it works but it fails only when i use the variables that are initialized in Test.h with interface builder.

Initialization :

IBOutlet UILabel *labelalco;

Interface builder :

this is another screen shot of where the test and the 'drink' section which is rootviewcontroller is shown .

THANKS

Answer 1

It's possible that your init method is passing back nil, instead of an object. If this is the case, than the -afficher method is sent to nil, which doesn't break, but doesn't DO anything. Check your return value after the alloc/init.

Answer 2

Since you say an NSLog message within the afficher method is written to the console, your method is empirically being called. That is doesn't do what you intend it to do is a bug in your code. From the minimal listing you've provided, I'd guess that poids and lableco are not initialized properly (meaning they're still nil when you method is called).

Answer 3

If you're using IBOutlet in -init method, it won't work there (I guess it's set to nil), but it should work in -awakeFromNib method.

Answer 4

I echo what was stated above. Your afficher is likely getting invoked if you see the "hello" output in your console. (To be absolutely certain, clear your console prior to running and check that it shows again to rule out stale output.) One other thing I would suggest is to use an NSAssert() to be sure your outlets are set. Here's an example:

-(void) afficher{

   NSLog(@"hello");
   NSAssert(nil!=poids, @"poids should be set.");
   poids.text = [NSString stringWithFormat:@"lol"];
   NSAssert(nil!= labelalco, @"labelalco should be set.");
   labelalco.text = [NSString stringWithFormat:@"cac"];

}

I just looked very closely at your screen shots and it appears that your Test object is a UIViewController. From the things you describe I bet you're assuming the labelalco to be set via interface builder connections. That will not happen in your 1st code snippet because you instantiate it directly without using the nib file.

Test *myLevelObject = [[Test alloc] init];
[myLevelObject afficher];

should be:

Test *myLevelObject = [[Test alloc] initWithNibName:@"Test.xib" bundle:nil];
[myLevelObject afficher];

Assuming Test.xib is where the connections are made in IB. It looks like this is a sub controller in your main window's tab view controller so there may be additional complexity in what you're trying to do.

Answer 5

Your latest comments say you're using a UITabBarController that contains RootViewController and Test.

But in RootViewController, you're trying to call a method in Test by creating a new instance of it. This instance would be separate from the one the tabbarcontroller is using.

I think in RootViewController, you need to instead obtain a reference to the same instance of Test the tabbarcontroller is using.

See this post for a possible way to do this:

http://stackoverflow.com/questions/2083351/iphone-sdk-how-to-access-a-viewcontroller-nested-in-a-tabbar-from-myappdelegate

However, why do you have code in RootViewController that updates Test? If Test is displayed, could it not update itself instead? How does the code in RootViewController get executed after Test has already been displayed?