How to Delete Row from Table View from other ViewController - ios

Question

So I have a DetailViewController which displays the details of row/cell from table view. Now I would like to add an option of DELETE on this controller. I added a Bar Button Item(trash) on it. How will I be able to delete the current row/data and remove it also from the TableViewController?
TableViewController
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
WishlistItem *wish = [self.wishlistItem objectAtIndex:indexPath.row];
DetailViewController *dvc = [self.storyboard instantiateViewControllerWithIdentifier:#"dvcID"];
dvc.wishItemStr = wish.wishlistItem;
dvc.dateItemStr = wish.targetDate;
dvc.descItemStr = wish.descWishItem;
[self.navigationController pushViewController:dvc animated:YES];
}

Answer 1

When you create the detailed view controller you must be initializing it with some data relevant to the row. So you can extent that initializer method (or add a new method if you like) which takes a block.
When the table view controller creates and loads the detailed view controller it initializes it with some block code that will delete the relevant row.
Example: (note I haven't compiled this).
Add this to the DetailViewController:
#property (copy, nonatomic) void (^deleteRowBlock)(void);
- (void) onDeletion:(void (^)(void)) deletionBlock;
The implementation of onDeletion is
- (void) onDeletion:(void (^)(void)) deletionBlock
{
self.deleteRowBlock = deletionBlock;
}
When the button is pressed in the DetailViewController call the block like this:
self.deleteRowBlock();
Then in didSelectRowAtIndexPath: add this:
[dvc onDeletion:^{
code to delete the row and update your data model
}];
Then when the button is pressed the "code to delete the row and update your data model" will get executed.
Or alternatively if you don't like blocks (but you should learn to like them) define a protocol with a method such as onDelete:(NSIndexPath*) row. The table view is a delegate of the detailed view and implements the protocol method, which you invoke when the button is pressed.
The detailed view would need to know its row number. Alternatively remove the NSIndexPath as the parameter to onDelete and have the tableView cache the row number of the currently presented detail view controller and when onDelete is called it deletes the row for the cached row number.
But it is preferable to use blocks

Answer 2

well, this is another solution,
1) pass self.wishListItem to DetailViewController, here is example
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
DetailViewController *dvc = [self.storyboard instantiateViewControllerWithIdentifier:#"dvcID"];
...
[dvc setWishListItem:self.wishListItem];
...
[self.navigationController pushViewController:dvc animated:YES];
}
2) in TableViewController implement viewWillAppear method like this
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.tableView reloadData];
}
3) in DetailViewController you have a delete button, right ? here is your button's action method
- (void)onDelete {
// your deleting stuff ...
[self.wishListItem removeObjectAtIndex:self.currentItemIndex]; // this line updates shared data
}
So TableViewController reloads it's data and keeps cells up to date once you get back (by touching back button, for example)
if you still have questions feel free to comment.