Adding Section Headers to UITableView - objective-c

Question

Forgive the noob question, still learning.
I have a UITableView with a single array for data (approx 50). I'm looking to implement section headers but I just can't get my head around it. All the information I can find seems to vary greatly (there seems to be manes ways it can be implemented?) and I can't seem to piece it all together!
As ever I can't make out the Apple docs but I think that's down to my inexperience.
So a few questions:
I understand I need to state how many sections are needed, with a single array, would would be the best way?
Can I use a single array? Or am I going to need to break it down into numerous arrays, each with their own section?
Thanks in advance.
Code for cellForRowAtIndexPath for jonkroll
switch (section) {
case 0:
cell.textLabel.text = (NSString*)[tableViewArray objectAtIndex:row];
break;
case 1:
cell.textLabel.text = (NSString*)[tableViewArray objectAtIndex:row+3];
break;
case 2:
cell.textLabel.text = (NSString*)[tableViewArray objectAtIndex:row+17];
break;
}

Answer 1

The methods in the UITableViewDataSource protocol let you to define how the tableView renders your data.
Use numberOfSectionsInTableView: to tell your table how many sections it will have.
Use numberOfRowsInSection: to tell your table how many rows will be in each section.
Use cellForRowAtIndexPath: to tell your table what to render in a particular cell based on indexPath (indexPath is a structure that identifies a particular cell based on section and row)
So you say you have a single array that you want to display in more than one section. This is a very contrived example, but let's say you want rows 1-30 to be in the first section and rows 31-50 to be in the second section.
You can do the following:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 2;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
switch (section) {
case 0: return 30; break;
case 1: return 20; break;
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
int section = [indexPath section];
int row = [indexPath row];
NSString* CellIdentifier = #"MyCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier] autorelease];
}
switch (section) {
case 0:
cell.textLabel.text = (NSString*)[array objectAtIndex:row];
break;
case 1:
cell.textLabel.text = (NSString*)[array objectAtIndex:row+30];
break;
}
return cell;
}

Answer 2

You application probably has an UITableViewDataSource and UITableViewDelegate (this is where you return the elements of the array and configure the number of sections, etc.). Within that class (or those classes if they're separate) there's two approaches you can take depending on what you'd like to do.
If you just want to have a title with the default look, implement tableView:titleForHeaderInSection: to return the title you want for each section.
If you want a custom view, implement tableView:viewForHeaderInSection: as well as tableView:heightForHeaderInSection: to return the custom view along with the height of the header views.

Answer 3

If you want a header consider using a UITableViewCustomCell, drag one into the nib where you have your tableView set up. Declare and link up in InterfaceBuilder.
IBOutlet UITableViewCell *cellOne;
#property (nonatomic, retain) IBOutlet UITableViewCell *cellOne;
Then you can use to assign the CellView to the Table view for your header.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if ([array count] == 0) return cellone;

Answer 4

You should look at the iPhoneCoreDataRecipes example that Apple puts out. They use a Tableview and show the data different ways. Being new at programming myself, I don't know how to provide the link to you, but it's in the iOS 5.0 Library under Data Management.