using swipe gesture to delete row on tableview

问题

I am trying to bypass the red button delete (editingstyledelete) by setting up a gesture of swipe and then using IBAction to call a delete of the row that the swipe was performed in. The app crashes and I get a error of : NSInvalidArgumentException', reason: '*** -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]

- (IBAction)deleteSwipe:(id)sender{
    [self deleteRow:self.tableView forCell:sender];
}

-(void) deleteRow:(UITableView *)tableView forCell:(UITableViewCell *)bCell{
    NSIndexPath *indexPath = [tableView indexPathForCell:bCell];
    [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
    [self.queue removeObjectAtIndex:indexPath.row];
    [tableView reloadData];
}

i setup a breakpoint exception and it points to the: [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; and in the report log it says that the index path value is nil. I have used the 'deleteRowsAtIndexPaths' method before and did not find this problem.

edit: updated code:

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        [self.queue removeObjectAtIndex:indexPath.row];
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationLeft];
        [self.tableView reloadData];
        }
}

-(UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath{
    return UITableViewCellEditingStyleNone;


}


-(BOOL) tableView:(UITableView *)tableView shouldIndentWhileEditingRowAtIndexPath:(NSIndexPath *)indexPath{
    return NO;
}

-(BOOL) tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath{
    return YES;
}


- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the item to be re-orderable.
    return YES;
}

回答1:

You can do this by implementing following UITableView deligate methods

- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath{
    return UITableViewCellEditingStyleNone; //if you don't want to show delete button
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
        return YES; // allow that row to swipe
        //return NO; // not allow that row to swipe
}

// Override to support editing/deleteing the table view cell on swipe.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleNone)
    {
        //--- your code for delete -----
    }
}

来源：https://stackoverflow.com/questions/21980208/using-swipe-gesture-to-delete-row-on-tableview

标签

objective-c

uitableview

xcode5

nsindexpath