How to have a UITableView link to another UITableView - ios

Question

I am currently making an app using swift that has information about cars.
I am using an UITableView for makes, models, years.
What I want to know is if can I have an UITableView linked to another UITableView depending on user input, for example:
tableview 1 (makes)
Audi
Honda
tableview 2 (Models)
Audi -> A1, A2, A3........
Honda -> Civic, Jazz...
tableview 3 (years)
Audi -> A3 -> 2005,2006,2007.....
Honda -> Civic -> 2005,2006,2007.....
Code for tableview 1
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.Makes = [Make(name: "Audi"),Make(name: "Nissan"),Make(name: "Fiat"),Make(name: "Ford"),Make(name: "Honda"),Make(name: "Mercedes-Benz"),Make(name: "Lexus"),Make(name: "BMW"),Make(name: "Vauxhall"),Make(name: "VW")]
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.Makes.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! UITableViewCell
var make = Makes[indexPath.row]
cell.textLabel?.text = make.name
return cell
}

Answer 1

1.- Organise your data in a good manner, maybe a graph, a tree, or simply lists relating all of your data.
2.- For simplicity makes functions that will give you corresponding data to each tableview.
Lets say:
func getModels(make: Makes) -> [Model]
func getYears(model: Model) -> [Years]
or simply
func getModels(make: String) -> [String]
func getYears(model: String) -> [String]
also, some helper functions that will allow you to implement any data structure behind, just like, for example:
func getMaker(int:Int) -> Maker? or func getMaker(int: Int) -> String?
3.- You must keep in memory which of your possible makers and models have been selected, for now, keep it like:
var selectedMaker: String?
var selectedModel: String?
4.- I assume you will have all your UITableViews at the same UIViewController or UITableViewController, so you will need to decide corresponding data to show to every one.
For this you will need to differentiate each one, how is up to show, with tags, instance equality, etc. I suggest for later readability and facility of use to end up having a function that will return a number? maybe, corresponding to the tableview. For this explanation sake, lets call it func whichTableIsThis(tableView: UITableView) -> Int?
5.- Your delegates should work different for everyone of those tableviews. Here we will be using our brand new function that must return 1, 2 or 3 ..nil if this tableview is not one of those. :)
extension YourViewControlerWithTableViews: UITableViewDelegate, UITableViewDataSource {
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
//I'm assuming you will have only one cell, lets call it `AttributesTableViewCell`
var cell = tableView.dequeueReusableCellWithIdentifier("yourCellName", forIndexPath: indexPath) as! AttributesTableViewCell
cell.attributeValue.text = ""
if let tableNumber = whichTableIsThis(tableView) {
//here you will be checking for every of your tree cases, for this example I will check just for Models
//OK, so tableNumber returned 2
if tableNumber == 2 && selectedMaker != nil{
let value = getModels(selectedMaker!)[indexPath.row]
cell.attributeValue.text = value
}
//...
}
return cell
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let tableNumber = whichTableIsThis(tableView) {
//here you will be checking for every of your tree cases, for this example I will check just for Models
//OK, so tableNumber returned 2
if tableNumber == 2 && selectedMaker != nil{
return getModels(selectedMaker!).count
}
//...
}
return 0
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
if let tableNumber = whichTableIsThis(tableView) {
//here you will be checking for every of your tree cases, for this example I will check just for Maker
//OK, so tableNumber returned 1
if tableNumber == 1 {
selectedMaker = getMaker(indexPath.row)
//Here you must refresh data for your next tables in hierarchy, to allow them to refresh with new data
selectedModel = nil
selectedYear = nil
tableview2.reloadData()
tableview3.reloadData()
}
//...
}
}
}
And..that should be all. Hope it helps!

Answer 2

This approach of drilling down to see more details is very common, and Xcode even provides a template to illustrate this, called Master-Detail.
The way this works is when you select a row in the first (or Master) tableView, it performs a showDetail segue to the second (or detail) tableViewController.
In prepareForSegue, you would get the indexPath of the selected row, and pass the make to the detail (destination) view controller. That view controller would then show all the models for that make of car.
You would use the same process in the detail tableView to pass a specific model to the a third tableViewController to see all years for that make and model.
override func prepareForSegue(segue: UIStoryboardSegue,
sender: AnyObject?) {
if segue.identifier == "showDetail" {
if let indexPath = self.tableView.indexPathForSelectedRow() {
Let make = Makes[indexPath.row]
let controller = (segue.destinationViewController
as UINavigationController).topViewController
as! DetailViewController
controller.detailItem = make
controller.navigationItem.leftBarButtonItem =
splitViewController?.displayModeButtonItem()
controller.navigationItem.leftItemsSupplementBackButton = true
}
}
}
Update:
The Master-Detail template provides other benefits, such as Adaptive UI. For example, on an iPad or iPhone 6 Plus, the user could choose to see both the master and detail views in a split view.