Problems trying to override methods in Objective-C (iPhone)

Question

Hello there, this my problem i have a class X that inherits UITableViewController class and a class Y that inherits the X class, when i try to override a method in the Y class the method in the X class is invoked... and i can't find references to understand what's happening... can anyone help me?

Thanks in advance!

Code!

mluListBuilder.h

#import <UIKit/UIKit.h>

@interface mluListBuilder : UITableViewController {
    NSString    *sListTitle;
    NSString    *sEntityName;
    NSArray     *aEntityProperties;
    NSMutableArray   *maListRecords;
    NSManagedObjectContext *mocList;
    NSFetchRequest   *frListRecords;
    NSEntityDescription  *edListRecords;
    NSArray     *aOrderByProperties;
    NSArray     *aToolBarItems;
    NSArray     *aToolBarItemsActions;
}

@property (nonatomic, retain) NSString      *sListTitle;
@property (nonatomic, retain) NSString      *sEntityName;
@property (nonatomic, retain) NSArray       *aEntityProperties;
@property (nonatomic, retain) NSMutableArray      *maListRecords;
@property (nonatomic, retain) NSManagedObjectContext    *mocList;
@property (nonatomic, retain) NSFetchRequest      *frListRecords;
@property (nonatomic, retain) NSEntityDescription    *edListRecords;
@property (nonatomic, retain) NSArray       *aOrderByProperties;
@property (nonatomic, retain) NSArray       *aToolBarItems;
@property (nonatomic, retain) NSArray       *aToolBarItemsActions;


- (id) initWithStyle:     (UITableViewStyle) style
    listTitle:     (NSString *)  psListTitle
    entityName:     (NSString *)  psEntityName 
    entityProperties:   (NSArray *)   paEntityProperties
    orderListByProperties:  (NSArray *)   paOrderByProperties
    toolBarItems:    (NSArray *)   paToolBarItems
    toolBarItemsActions:  (NSArray *)   paToolBarItemsActions;

- (void)newRecord;
- (void)deleteRecord;

@end

mluListBuilder.m

#import "mluListBuilder.h"

@implementation mluListBuilder

@synthesize sListTitle,
      sEntityName,
      aEntityProperties,
      maListRecords,
      mocList,
      frListRecords,
      edListRecords,
      aOrderByProperties,
      aToolBarItems,
      aToolBarItemsActions;


- (id) initWithStyle:     (UITableViewStyle) style
    listTitle:     (NSString *)  psListTitle
    entityName:     (NSString *)  psEntityName 
    entityProperties:   (NSArray *)   paEntityProperties
    orderListByProperties:  (NSArray *)   paOrderByProperties
    toolBarItems:    (NSArray *)   paToolBarItems
    toolBarItemsActions:  (NSArray *)   paToolBarItemsActions
{

    sListTitle    = psListTitle;
    sEntityName    = psEntityName;
    aEntityProperties  = paEntityProperties;
    aOrderByProperties  = paOrderByProperties;
    aToolBarItems   = paToolBarItems;
    aToolBarItemsActions = paToolBarItemsActions;

    if (self = [super initWithStyle:style]) {
    }
    return self;
}

- (void)viewDidLoad {
    self.title = NSLocalizedString(sListTitle, nil);

    if ([aToolBarItems count] > 0) {
     NSMutableArray *maToolBarItems = [[NSMutableArray alloc] init];
     self.navigationController.toolbarHidden = NO;
     for (int i = 0; i < [aToolBarItems count]; i++) {
      UIBarButtonItem * bbiToolBarItem = [[UIBarButtonItem alloc] 
               initWithTitle:NSLocalizedString([aToolBarItems objectAtIndex:i], nil)
               style:UIBarButtonItemStyleBordered
               target:self 
               action:NSSelectorFromString([aToolBarItemsActions objectAtIndex:i])
               ];


      [maToolBarItems addObject:bbiToolBarItem];
     }
     self.toolbarItems = maToolBarItems;
    } else {
     self.navigationController.toolbarHidden = YES;
    }

    if (mocList != nil) {
     frListRecords = [[NSFetchRequest alloc] init];

     NSSortDescriptor *sdListRecords = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];

     [frListRecords setSortDescriptors:[[NSArray alloc] initWithObjects:sdListRecords, nil]];

     edListRecords = [NSEntityDescription entityForName:sEntityName inManagedObjectContext:mocList];

     [frListRecords setEntity:edListRecords];

     NSError *errFetchRequest;
     maListRecords = [[mocList executeFetchRequest:frListRecords error:&errFetchRequest] mutableCopy];
    }
    [super viewDidLoad];
}

- (void)viewWillAppear:(BOOL)animated {
    NSError *errFetchRequest;
    maListRecords = [[mocList executeFetchRequest:frListRecords error:&errFetchRequest] mutableCopy];
    [self.tableView reloadData];

    if (self.navigationController.toolbarHidden == YES) {
     if ([aToolBarItems count] > 0) {
      self.navigationController.toolbarHidden = NO;
     }
    }
}

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


#pragma mark Table view methods

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}


// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [maListRecords count];
}


// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }

    for (UIView *vwExisting in cell.contentView.subviews) {
     [vwExisting removeFromSuperview];
    }

    NSEntityDescription *edCurrentRecord = [maListRecords objectAtIndex:indexPath.row];

    UILabel *lblCell = [[UILabel alloc] initWithFrame:CGRectMake(5.0, 5.0, 280, 20.0)];
    [lblCell setText:edCurrentRecord.name];

    [cell.contentView addSubview:lblCell];

    [cell setSelectionStyle:UITableViewCellSelectionStyleNone];

    return cell;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    // Navigation logic may go here. Create and push another view controller.
    // AnotherViewController *anotherViewController = [[AnotherViewController alloc] initWithNibName:@"AnotherView" bundle:nil];
    // [self.navigationController pushViewController:anotherViewController];
    // [anotherViewController release];
}

- (void)dealloc {
    [super dealloc];
}

- (void)newRecord {
    NSLog(@"%@", [self class]);
}

- (void)deleteRecord {

}

@end

mluLawyerCaseSituationsList.h

#import <Foundation/Foundation.h>
#import "mluListBuilder.h";

@interface mluLawyerCaseSituationsList : mluListBuilder {

}

- (void)newRecord;

@end

mluLawyerCaseSituationsList.m

#import "mluLawyerCaseSituationsList.h"

@implementation mluLawyerCaseSituationsList

- (void)newRecord {
    NSLog(@"%@", [self class]);
}

@end

Calling the mluLawyerCaseSituationsList

mluLawyerCaseSituationsList *vcCaseSituations = [[mluListBuilder alloc]
                 initWithStyle:UITableViewStylePlain
                 listTitle:@"titCaseSituations" 
                 entityName:@"case_situations" 
                 entityProperties:[[NSArray alloc] initWithObjects:@"name", nil] 
                 orderListByProperties:[[NSArray alloc] initWithObjects:@"name", nil] 
                 toolBarItems:[[NSArray alloc] initWithObjects:@"btNew", nil]
                 toolBarItemsActions:[[NSArray alloc] initWithObjects:@"newRecord", nil]
                 ];

Output... :(

2009-12-17 17:30:02.726 mluLawyer[2862:20b] mluListBuilder

Hope it helps...

Answer 1

So, you have:

@interface X : UITableViewController
- (void) method;
@end

@interface Y : X
- (void) method;
@end

You are calling -method, but it is being invoked on X, not Y? Only way that can happen is if you have an instance of X instead of Y (or if someone is playing very silly buggers with the runtime -- unlikely).

Add NSLog(@"%@", [self class]); to the method implementations and see what the class of the instance really is!

Answer 2

You don't give us much information in your question, but the following is how it should work:

Class_X.h:

@interface Class_X : UITableViewController
{
}
- (void)someMethod;
@end

Class_X.m:

#import "Class_X.h"

@implementation Class_X
- (void)someMethod
{
    NSLog(@"method in Class_X was called");
}
@end

Class_Y.h:

#import "Class_X.h"

@interface Class_Y : Class_X
{
}
- (void)someMethod;
@end

Class_Y.m:

#import "Class_Y.h"

@implementation Class_Y
- (void)someMethod
{
    NSLog(@"method in Class_Y was called");
}
@end

Elsewhere:

#import "Class_Y.h"

...

Class_X * x_instance = [[Class_X alloc] init];
Class_Y * y_instance = [[Class_Y alloc] init];

[x_instance someMethod];
[y_instance someMethod];

[Class_Y release];
[Class_X release];

Output:

method in Class_X was called
method in Class_Y was called

Answer 3

I’ve been looking through your code only briefly, but it seems obvious (from code and from the output) that you allocate an instance of class X (mluListBuilder).

Of course, you cannot expect to have a method of class Y (mluLawyerCaseSituationsList), performed when Y is derived from X and the object is of class X.

Answer 4

Sorry about that... too much work... :S Thanks for all and sorry about the time i've taken from you...

Shame on me...