How to pop up UIAlertView when the numberofrow (TableView) is 1 - objective-c

Question

I have an 'add' button to create new row of tableview. And the number of row is limited to one.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return 1;
}
I'd like the button to pop up an alert view when there is one row, not allowing to create a new row.
However i don't know how to implement an 'if condition' in the Button action as following:
- (IBAction)add
{
if (condition)
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Title" message:#"Hi" delegate:self cancelButtonTitle:#"Done" otherButtonTitles:nil];
}
[alert show];
}
Please Help! Sorry for not being professional, I'm trying to learn objective c

Answer 1

All you have to do is -
- (IBAction)add
{
if ([self.tableView numberOfRowsInSection:0] == 1)
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Title" message:#"Hi" delegate:self cancelButtonTitle:#"Done" otherButtonTitles:nil];
}
[alert show];
}

Answer 2

I think you need have an mutableArray to hold the data of UITableView and return the count of array provide to UITableView through "numberOfRowsInSection" method, when you want to add a row , you just add a data into the Array and reload the tableView.
ps:you can't add row but return 1 to UITableView

Answer 3

Create boolean variable shouldCreateRow.
Write the tableview datasource method as
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
if(shouldCreateRow){
return 1;
}
}
and the action method as
- (IBAction)add:(UIButton *)sender {
sender.selected=!sender.selected;
if (sender.selected && !shouldCreateRow) {
UIAlertView *alert=[[UIAlertView alloc]initWithTitle:#"Alert" message:#"One row created" delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
[alert show];
shouldCreateRow=TRUE;
[myTable reloadData];
}else{
UIAlertView *alert=[[UIAlertView alloc]initWithTitle:#"Alert" message:#"Already there is One row." delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
[alert show];
}
}