每次进入视图时，在数组中添加一个对象

Question

how can I add an object in my array each time I enter to my TableView I put this code in viewDidLoad and viewDidAppear methods but it seems to doesn't work :

- (void)viewDidLoad
{
    [super viewDidLoad];

    if (!myArray) {
        myArray = [[NSMutableArray alloc] init];
    }
    [peopleListe insertObject:[NSDate date] atIndex:0];
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
    [self.tableView insertRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
    NSLog(@"%@",myArray);

}

when I put this code in a button it works

Thank you for your help

Answer 1

viewDidLoad is called once, when the view loads.

viewWillAppear is called every time you go into that view.

If you want to do something each time a view appears, put the code in viewWillAppear .

EDIT: It's possible that your array is getting dealloc'd. Try setting a breakpoint in dealloc as a simple way to see if that's the case:

- (void)dealloc {
    NSLog(@"BYE!); // <-- put your breakpoint here
}

If it is, you'll have to (a) store your data somewhere else, or (b) keep this view/controller from being dealloced.

Also, who is your tableViewDelegate ? That will have to implement methods returning the number of items in the table view and so on. I recommend having a read through the docs to get all those relationships sorted out.

Answer 2

You don't want to have that array as a property/ivar of your view controller. The view controller may, and will, get deallocated when it's not used (eg if it's inside the navigation controller, and you tap the "back" button to go to the previous screen.) When the view controller gets deallocated, your array obviously ceases to exist.

I suggest creating keeping that array in a separate place, eg in a singleton data object, or even (as a quick short-term solution) your app delegate.

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About the code you posted: keep in mind that [UIViewController viewDidLoad] is only called once during the view controller's lifecycle. It may get called more than once, but that would mean that the original instance has been dealloc'd (and your original array is gone).