How to delete a row from UITableView? [duplicate] - ios

Question

This question already has answers here:
How to delete a row from UITableView
(5 answers)
Closed 9 years ago.
I want to delete a row from a tableView by using alertView message to confirm, but got some error output:
reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (3) must be equal to the number of rows contained in that section before the update (3), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'
Setup some of private member in SomeViewController interface
#interface SomeViewController ()
{
NSMutableArray *listItems;
NSString *itemId;
NSIndexPath *rowIndexPath;
}
In SomeViewController.m
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return [listItems count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [[listItems objectAtIndex:section] count];
}
#pragma mark - Table view operation
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
//add code here for when you hit delete
UIAlertView *deleteAlert = [[UIAlertView alloc] initWithTitle:#"Message"
message:#"Are you sure?"
delegate:self
cancelButtonTitle:#"OK"
otherButtonTitles:#"Cancel", nil];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
itemId = cell.textLabel.text;
rowIndexPath = indexPath;
deleteAlert.tag = 1;
[deleteAlert show];
}
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (alertView.tag == 1)
{
if (buttonIndex == 0) {
NSLog(#"itemId: %#", itemId);
NSLog(#"rowIndexPath: %#", rowIndexPath);
[self.tableView beginUpdates];
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:rowIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
[self.tableView endUpdates];
[self.tableView reloadData];
}
}
}
I can correctly set the tableView data and show deletion option, but can't figure it out why that error occurred.

Answer 1

Delete the datasource before you delete cell.
Hope it helps
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (alertView.tag == 1)
{
if (buttonIndex == 0) {
NSLog(#"itemId: %#", itemId);
NSLog(#"rowIndexPath: %#", rowIndexPath);
[self.tableView beginUpdates];
[[listItems objectAtIndex:section] removeObjectAtIndex:rowIndexPath.row]
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:rowIndexPath]
withRowAnimation:UITableViewRowAnimationFade];
[self.tableView endUpdates];
[self.tableView reloadData];
}
}

Answer 2

Remember every time you do a delete action, you should always modify your data source first.

Answer 3

You can simply remove the object from the array, then reload the UITableView. Like So:
[YourArray removeObjectAtIndex:1]; //Change the index to which cell you want to "delete"
[YourTableView reloadData];
Or do as stated here: How to delete a row from UITableView.