Dynamically Implementing Section in cellForRowAtIndexPath - ios

Question

I am not able to wrap my head around the implementation of sections in cellForRowAtIndexPath.
I have a UITableView in which I would like to show 2 sections.
Incoming Friend Requests
Friends
In Storyboard, I change my UITableView Style to Grouped.
Next, I would like there to be no Friend Request section if there are no friend requests. In viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
(...)
if friendRequests.isEmpty {
friendsDataSource = friends
} else {
friendsDataSource = [friendRequests, friends]
}
}
The rest:
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return friendsDataSource.count
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return friendsDataSource[section].count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let friendRequest = friendsDataSource[0][indexPath.row]
let friend = friendsDataSource[1][indexPath.row]
if let cell = tableView.dequeueReusableCellWithIdentifier("FriendCell") as? FriendCell {
cell.configureProfileCell(userProfile)
return cell
} else {
return FriendCell()
}
}
I know my cellForRowAtIndexPath is disgusting but I have absolutely no idea how to implement it.
Any help in the right direction, greatly appreciated

Answer 1

Discovered if (indexPath.section == 0), and I just hacked around that.
My eyes hurt looking at this so Please post better ways of doing this. For now:
var friendRequests = [FriendRequest]()
var friends = [UserProfile]()
var friendsDataSource = []
override func viewDidLoad() {
super.viewDidLoad()
friends = FriendManager.instance.myFriends
friendRequests = FriendManager.instance.incomingFriendRequests
if friendRequests.isEmpty {
friendsDataSource = [friends]
} else {
friendsDataSource = [friendRequests, friends]
}
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return friendsDataSource.count
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return friendsDataSource[section].count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCellWithIdentifier("FriendCell", forIndexPath: indexPath) as? FriendCell {
if friendRequests.isEmpty {
let friendCell = friends[indexPath.row]
cell.configureProfileCell(friendCell)
} else {
if (indexPath.section == 0) {
let friendRequestCell = friendRequests[indexPath.row]
cell.configureRequestCell(friendRequestCell)
} else if (indexPath.section == 1) {
let friendCell = friends[indexPath.row]
cell.configureProfileCell(friendCell)
}
}
return cell
} else {
return FriendCell()
}
}

Answer 2

You should use the other, newer dequeueing method: dequeReusableCellWithIdentifier(_:forIndexPath:) instead (passing the actual index path).
That one is guaranteed to always succeed, so you can do without this if/else structure:
if let cell = ... {
...
return cell
}
else {
return FriendCell()
}
By the way, you are returning the FriendCell instance fresh, without configuring it. Is that what you really want?
Clarification
The method dequeReusableCellWithIdentifier(:) succeeds only if there is one or more cells with the specified identifier already enqueued for reuse; the first few times you call it it will return nil and you need to fallback to instantiating a new cell (with the same identifier), for immediate use (and later reuse):
func tableView(tableView:UITableView, cellForRowAtIndexPath:NSIndexPath) -> UITableViewCell
{
if let cell = tableView.dequeReusableCellWithIdentifier("Identifier") as? FriendCell {
// Successfully dequeued for reuse;
// configure it:
// (set labels' texts, etc.)
return cell
}
else{
// No cell enqueued; create anew
let cell = FriendCell(style:.Plain, reuseIdentifier:"Identifier")
// configure it
// (set labels' texts, etc.)
return cell
}
}
...But because this check is a pain, Apple added a new method:
dequeReusableCellWithIdentifier(identifier:String, forIndexPath:NSIndexPath)
that internally performs the dequeueing and also initializes a new cell if no one is available. This eliminates the need for an else path in the code above, and it gets smarter:
func tableView(tableView:UITableView, cellForRowAtIndexPath:NSIndexPath) -> UITableViewCell
{
let cell = tableView.dequeReusableCellWithIdentifier("Identifier", forIndexPath:indexPath) as! FriendCell
// (Never fails - provided identifier is right and class is registered for it)
// configure it:
// (set labels' texts, etc.)
return cell
}