Confusion about the para indexPath of cellForRowAtIndexPath in iOS - ios

Question

I'm new to iOS dev so this might be a simple question to you but I check the apple dev guide just could not find it.
I have many UITableViews using one dataSourceDelegate,this is how I create them：
- (void)createSomeTableview:(NSInteger)numberOfTableViews{
tableViewsArray = [[NSMutableArray alloc] initWithCapacity:numberOfTableViews];
for (int i = 0; i < numberOfTableViews; i++) {
UITableView *itemTableView = [[UITableView alloc] initWithFrame:CGRectMake(90, 0, 235, self.view.bounds.size.height) style:UITableViewStylePlain];
[itemTableView setDataSource:self];
[itemTableView setDelegate:self];
[itemTableView registerClass:[KKYItemListCell class] forCellReuseIdentifier:[NSString stringWithFormat:#"%ld", (long)currentSection]];
[tableViewsArray addObject:itemTableView];
[[self view] addSubview:itemTableView];
}
}
I call createSomeTableview when I finish got my data back from my server,then I use a cycle to reload the data of each tableView (I call this in a block of AFNetwoking POST after got the response successfully):
for (int i = 0; i < sectionNum;i++){
currentSection = i;
[[tableViewsArray objectAtIndex:i] reloadData];
}
This is where the disaster came!(T T)There is always a null cell return from the reloading process so I track the reloading process and found a strange thing:
Once I call the method reloadData,the method numberOfRowsInSection is called (I have just one section for each table),after this then go back to call the reloadData of the next Tableview in tableViewsArray.(I used to think the reloadData will call cellForRowAtIndexPath next).
After all the views in tableViewsArray calling numberOfRowsInSection,the method cellForRowAtIndexPath had been called by the last view in tableViewsArray.Well that's fine,it starts to build the data for my tableview~,I do this to specify my tableViews in array:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
.....
if (tableView == sectionTableView) {
...
} else if (tableView == [tableViewsArray objectAtIndex:(long)currentSection]) {
...//data handle
if (itemsNum == 0) { //itemsNum is the count of current table's items
currentSection--; //if loaded end then go to the next tableView
return cell;
}
itemsNum--;
return cell;
}
return cell;
}
But something wrong with it!!! I got 18 items in the current data from server (itemsNum = 18),and I did get 18 return from numberOfRowsInSection.But when the indexPath.row == 6,the tableView's index is currentSection - 1,which means it's no longer the current tableView (actually it was the next tableView)is calling the method `cellForRowAtIndexPath'.
So (tableView == [tableViewsArray objectAtIndex:(long)currentSection]) is false,method return a nil cell,then crashed.
I'm wondering where does the method 'tableView:cellForRowAtIndexPath' get the para row in indexPath?Isn't the return of 'numberOfRowsInSection'?(not seemed like in my program).