I have a list of names sorted alphabetically, and now I want display these names in a table view. I'm struggling with grouping these names for each letter.
My code looks like this:
let sections:Array<AnyObject> = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
var usernames = [String]()
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
let cellID = "cell"
let cell: UITableViewCell = self.tv.dequeueReusableCellWithIdentifier(cellID) as UITableViewCell
cell.textLabel?.text = usernames[indexPath.row]
return cell
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
return usernames.count
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int{
return 26
}
func sectionIndexTitlesForTableView(tableView: UITableView) -> [AnyObject]!{
return self.sections
}
func tableView(tableView: UITableView,
sectionForSectionIndexTitle title: String,
atIndex index: Int) -> Int{
return index
}
func tableView(tableView: UITableView,
titleForHeaderInSection section: Int) -> String?{
return self.sections[section] as? String
}
and it all works pretty good except for the grouping which makes my table view end up like this:
So I know you should be able to use the filtered function in an Array, but I did not understand how to implement it.
Any suggestions on how to proceed would be appreciated.
You can put your arrays with names into dictionary with letter keys.
For example
var names = ["a": ["and", "array"], "b": ["bit", "boring"]]; // dictionary with arrays setted for letter keys
then you need to access values in your dictionary in the next way
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
return names[usernames[section]].count; // maybe here is needed to convert result of names[...] to NSArray before you can access count property
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
let cellID = "cell"
let cell: UITableViewCell = self.tv.dequeueReusableCellWithIdentifier(cellID) as UITableViewCell
cell.textLabel?.text = names[usernames[indexPath.section]][indexPath.row]; // here you access elements in arrray which is stored in names dictionary for usernames[indexPath.section] key
return cell
}
This is how I recently implemented sorted list in a tableView in Swift programmatically,
import UIKit
class BreedController: UITableViewController{
var breeds = ["A": ["Affenpoo", "Affenpug", "Affenshire", "Affenwich", "Afghan Collie", "Afghan Hound"], "B": ["Bagle Hound", "Boxer"]]
struct Objects {
var sectionName : String!
var sectionObjects : [String]!
}
var objectArray = [Objects]()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
tableView.registerClass(UITableViewCell.classForCoder(), forCellReuseIdentifier: "Cell")
// SORTING [SINCE A DICTIONARY IS AN UNSORTED LIST]
var sortedBreeds = sorted(breeds) { $0.0 < $1.0 }
for (key, value) in sortedBreeds {
println("\(key) -> \(value)")
objectArray.append(Objects(sectionName: key, sectionObjects: value))
}
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return objectArray.count
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return objectArray[section].sectionObjects.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! UITableViewCell
// SETTING UP YOUR CELL
cell.textLabel?.text = objectArray[indexPath.section].sectionObjects[indexPath.row]
return cell
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return objectArray[section].sectionName
}
}
In Swift 4 Dictionary(grouping:by:) was introduced to group a sequence to a dictionary by an arbitrary predicate.
This example maps the grouped dictionary to a custom struct Section
struct Section {
let letter : String
let names : [String]
}
...
let usernames = ["John", "Nancy", "James", "Jenna", "Sue", "Eric", "Sam"]
var sections = [Section]()
override func viewDidLoad() {
super.viewDidLoad()
// group the array to ["N": ["Nancy"], "S": ["Sue", "Sam"], "J": ["John", "James", "Jenna"], "E": ["Eric"]]
let groupedDictionary = Dictionary(grouping: usernames, by: {String($0.prefix(1))})
// get the keys and sort them
let keys = groupedDictionary.keys.sorted()
// map the sorted keys to a struct
sections = keys.map{ Section(letter: $0, names: groupedDictionary[$0]!.sorted()) }
self.tableView.reloadData()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cellID = "cell"
let cell = tableView.dequeueReusableCell(withIdentifier: cellID, for: indexPath)
let section = sections[indexPath.section]
let username = section.names[indexPath.row]
cell.textLabel?.text = username
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return sections[section].names.count
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int{
return sections.count
}
func sectionIndexTitles(for tableView: UITableView) -> [String]? {
return sections.map{$0.letter}
}
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return sections[section].letter
}
Download CountryList Json file and put in side your project
https://gist.github.com/keeguon/2310008
var json = NSArray()
var arr_name = NSArray()
var arrIndexSection : NSArray = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
override func viewDidLoad() {
let path = Bundle.main.path(forResource: "countries", ofType: "json")
let data = NSData(contentsOfFile: path! )
json = (try! JSONSerialization.jsonObject(with: data as! Data, options: JSONSerialization.ReadingOptions.mutableContainers)) as! NSArray
arr_name = json.value(forKey: "name") as! NSArray;
tableview.reloadData()
super.viewDidLoad()
}
// Side List in tableview
public func numberOfSections(in tableView: UITableView) -> Int {
return 26
}
public func sectionIndexTitles(for tableView: UITableView) -> [String]? {
return self.arrIndexSection as? [String] //Side Section title
}
public func tableView(_ tableView: UITableView, sectionForSectionIndexTitle title: String, at index: Int) -> Int
{
return index
}
public func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return arrIndexSection.object(at: section) as? String
}
// number of rows in table view
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
let predicate = NSPredicate(format: "SELF beginswith[c] %@", arrIndexSection.object(at: section) as! CVarArg)
let arrContacts = (arr_name as NSArray).filtered(using: predicate)
return arrContacts.count;
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell : TableViewCell=self.tableview.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell
let predicate = NSPredicate(format: "SELF beginswith[c] %@", arrIndexSection.object(at: indexPath.section) as! CVarArg)
let arrContacts = (arr_name as NSArray).filtered(using: predicate) as NSArray
cell.textLabel?.text = arrContacts.object(at: indexPath.row) as? String
return cell
}
Parveen Banu
var frndsName = ["Vanitha","Ilakkiya","Parveen","Divya","Seetha","Madhavi","Ashwini","Sangeetha","Swathi","Don","Priyanka","Tamilselvi","Premlatha","Prashanthi","Rekha","Ajitha","Praveena","Indhusree","Nisha","Priya","Lavanya","Sandhiya","Gejalakshmi","Pavithra","Abinaya"]
let sections = ["*","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","#"]
var dividedArray:NSMutableArray = []
override func viewDidLoad() {
super.viewDidLoad()
for i in sections{
let dummyArray:NSMutableArray = []
for j in frndsName{
if i.first! == j.first! {
dummyArray.add(j)
}
}
dividedArray.add(dummyArray)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 26
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return (dividedArray[section] as! NSMutableArray).count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")
let dummyArray = dividedArray[indexPath.section] as! NSMutableArray
cell?.textLabel?.text = dummyArray[indexPath.row] as? String
return cell!
}
func sectionIndexTitles(for tableView: UITableView) -> [String]? {
return self.sections
}
func tableView(_ tableView: UITableView, sectionForSectionIndexTitle title: String, at index: Int) -> Int {
return index
}
internal func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return self.sections[section] as String
}
}
In case, if your data array is not predefined, here's a way to achieve the same thing.
Let's say our class is ViewController.
class ViewController: UIViewController {
var contactDictionary = [String: [TTContact]]() //TTContact is a model, it has firstName and lastName properties
var keys = [String]()
var alphabets = (97...122).map { "\(Character(UnicodeScalar.init($0)))" }.map { $0.uppercased() } //Populating alphabets
... // other properties
override func viewDidLoad() {
super.viewDidLoad()
//set delegate and register cell for your tableView
self.setContacts()
}
private func self.setContacts() {
//Loop through your array, take the firstName, and the first character of that string.
//Check the uppercase value of that character, if it's an alphabet or not, otherwise, we'd place "#" for the names starting with a number in the header.
var temp = [String: [TTContact]]() //A temporary array
for contact in self.contacts {
if let firstName = contact.firstName, !firstName.isEmpty { //In my case, the firstName is an optional string
let firstChar = "\(firstName.first!)".uppercased()
if alphabets.contains(firstChar) {
var array = temp[firstChar] ?? []
array.append(contact)
temp[firstChar] = array
} else {
var array = temp["#"] ?? []
array.append(contact)
temp["#"] = array
}
}
}
self.keys = Array(temp.keys).sorted() //Populating and sorting all the keys alphabetically.
for key in self.keys { self.contactDictionary[key] = temp[key] }
//reload table
}
}
extension: ViewController: UITableViewDelegate, UITableViewDataSource {
func numberOfSections(in tableView: UITableView) -> Int {
return self.contactDictionary.count
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.contactDictionary[keys[section]]?.count ?? 0
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let key = self.keys[indexPath.section]
let cell: //dequeue your cell here.
if let row = self.contactDictionary[key]?[indexPath.row] {
cell.display(with: row) //Bind your cell's outlets with the properties
return cell
}
return UITableViewCell()
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let key = self.keys[indexPath.section]
if let row = self.contactDictionary[key]?[indexPath.row] {
//handle selection.
}
}
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? { //You can use viewForHeaderInSection either.
return self.keys[section]
}
}
来源：https://stackoverflow.com/questions/28087688/alphabetical-sections-in-table-table-view-in-swift