loadNibNamed at Base Class override the instance of Child Class

Question

I have class hierachy with

ParentCell extends UITableViewCell
ChildCell extends ParentCell

ParentCell have separate XIB, In child cell i was creating and adding only one button to one view at ParentCell XIB. but i cant add action for this button. Because even i was creating a instance for ChildCell, that returns the instance of ParentCell

Because i use loadNibNamed to get the XIB with IBOutlet connections. @ initWithStyle method in ParentCell Class

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        self = [[NSBundle mainBundle] loadNibNamed:@"ParentCell" owner:self options:nil]
               [0];
    }
    return self;
}

@ initWithStyle method in ChildCell Class

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        self.button=[[UIButton alloc] init];
        [self.contentView addSubview:button];
    }
    return self;
}

@ View Controller

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
            static NSString *CellIdentifier = @"ChildCell ";
            ChildCell *cell=[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
            if (cell == nil)
            {
              cell=[[ChildCell alloc] initWithStyle:UITableViewCellStyleDefault   reuseIdentifier:CellIdentifier];

                NSLog(@"Cell : %@", cell);  //this have instance of ParentCell instead of ChildCell
            }
}

Now temporarily solved by this way

@ initWithStyle method in ParentCell Class

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        NSBundle *mainBundle = [NSBundle mainBundle];
        NSArray *views = [mainBundle loadNibNamed:@"ParentCell"
                                            owner:self
                                          options:nil];
       //Here we are linking the view with appropriate IBOutlet by their tag
       self.lblTitle=[views[0] viewWithTag:100];
       self.lblContent=[views[0] viewWithTag:200];
    }
    return self;
}

@ initWithStyle method in ChildCell Class

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        self.button=[[UIButton alloc] init];
        [self.contentView addSubview:button];
    }
    return self;
}

But i don't know this is right approach to follow, or we have some other better approach then this..

score 1 · Answer 1 · answered Sep 03 '14 at 11:15

You should use the registerNib:forCellReuseIdentifier: method at the viewDidLoad of you UITableView class.

static NSString *parentCellIdentifier = @"parentCellIdentifier";
static NSString *childCellIdentifier = @"childCellIdentifier";

[self.tableView registerNib:[UINib nibWithNibName:@"ParentCell" bundle:nil] forCellReuseIdentifier:parentCellIdentifier];
[self.tableView registerNib:[UINib nibWithNibName:@"ChildCell" bundle:nil] forCellReuseIdentifier:childCellIdentifier];

(Don't forget to set the appropriate ReuseIdentifier at the XIB file)

This is the best practice, and you can get rid of your initWithStyle implementations.

loadNibNamed at Base Class override the instance of Child Class

1 Answers1