从UITableView外部TableView委托中删除行

Question

I am trying to delete a row from UITableview outside the delegate method. I am calling a method when I click a button inside a table cell and trying to delete the row inside that method. Here is the function I am using

UIButton *btn = (UIButton*)sender;
int tag = btn.tag;
UITableViewCell *buttonCell = (UITableViewCell*)[[btn superview] superview];
NSIndexPath *indexPath = [self.msgTbl indexPathForCell:buttonCell];
[deleg.rmessages removeObjectAtIndex:buttonRow];
[self.msgTbl deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationTop];NSInteger buttonRow = indexPath.row;
[self.msgTbl reloadData];

Using this one or two rows get deleted but after that its crashing giving exception

Number of rows before and after deletion must be same

How can I do this in ios? Thanks

Answer 1

Your problem is that the data that is being taken to populate your table isn't consistent with the table after deleting the cell. Make sure your dataSource methods provide the correct data after doing this (for example, if it is an array of objects you are using to populate the table, you must remove the object from the array as well)

Answer 2

The root issue is that this method:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;

Must return the correct number of rows, and it isn't. When you remove the item from deleg.rmessages , is this the same object that is being used to supply the return value of the above method? (Something like [deleg.rmessages count] ?)

Also, in my experience that exception often gives you more details, in particular:

1. How many items it had before
2. How many were added/deleted
3. How many it expects to have vs. how many it does have after the reload

Do you see anything like this being mentioned? If so, it would be worth including in your question.

Sidenote:

It's a bad idea to rely on:

UITableViewCell *buttonCell = (UITableViewCell*)[[btn superview] superview];

To return the UITableViewCell . You appear to assign the tag of the button to a local variable, but never use it. (Maybe this would be a good place to store the index of the UITableViewCell, and then subclass the cell to maintain an ivar to the button?) This is only part of the problem.