Add an Index to a searchBar - uitableview

Question

Need help to correct this code. I have a coredata app with restaurant names and address, have a search Bar and it is working. What I want to add is a Index and a IndexTitle as showed in the picture below (arrows). Any help is more than welcome. Thanks in advance.
import UIKit
import CoreData
class DictionaryTableViewController: UITableViewController, NSFetchedResultsControllerDelegate, UISearchResultsUpdating
{
var searchController:UISearchController!
var searchResults:[Dictionary] = []
private var dictionaryItems:[Dictionary] = []
var fetchResultController:NSFetchedResultsController!
override func viewDidLoad() {
super.viewDidLoad()
if let managedObjectContext = (UIApplication.sharedApplication().delegate as? AppDelegate)?.managedObjectContext {
let fetchRequest = NSFetchRequest(entityName: "DictionaryEntity")
do {
dictionaryItems = try managedObjectContext.executeFetchRequest(fetchRequest) as! [Dictionary]
} catch {
print("Failed to retrieve record")
print(error)
}
}
searchController = UISearchController(searchResultsController: nil)
tableView.tableHeaderView = searchController.searchBar
searchController.searchResultsUpdater = self
searchController.dimsBackgroundDuringPresentation = false
tableView.estimatedRowHeight = 30.0
tableView.rowHeight = UITableViewAutomaticDimension
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 26
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if searchController.active {
return searchResults.count
} else {
return dictionaryItems.count
}
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! DictionaryTableViewCell
// Configure the cell...
cell.wordLabel.text = dictionaryItems[indexPath.row].word
cell.definitionSmallLabel.text = dictionaryItems[indexPath.row].definition
let dictionary = (searchController.active) ? searchResults[indexPath.row]: dictionaryItems[indexPath.row]
// Configure the cell...
cell.wordLabel.text = dictionary.word
cell.definitionSmallLabel.text = dictionary.definition
return cell
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String?
{
return "dictionaryItems\(section)"
}
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
if searchController.active{
return false
}else{
return true
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showDictionaryDetail" {
if let indexPath = tableView.indexPathForSelectedRow {
let destinationController = segue.destinationViewController as! DictionaryDetailViewController
destinationController.dictionary = (searchController.active) ? searchResults[indexPath.row] : dictionaryItems[indexPath.row]
searchController.active = false
}
}
}
func updateSearchResultsForSearchController(searchController:
UISearchController) {
if let searchText = searchController.searchBar.text {
filterContentForSearchText(searchText)
tableView.reloadData()
}
}
func filterContentForSearchText(searchText: String) {
searchResults = dictionaryItems.filter({ (dictionary:Dictionary) -> Bool in
let wordMatch = dictionary.word!.rangeOfString(searchText, options:
NSStringCompareOptions.CaseInsensitiveSearch)
return wordMatch != nil
})
}
}
What I am trying to have in my table View is the Index (Arrows in the left) and the Index Title (Arrows in the right side).

Answer 1

You have typos in your override function for titleForHeaderInSection
Here is the corrected one, note that v in tableView is capital: (copy paste my code)
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
}
I'd recommend using the auto-complete feature of Xcode. that way, you don't get stuck in insidious errors like this.
UPDATE:
You also need to provide both of these methods to see section header and section index titles.
override func sectionIndexTitlesForTableView(tableView: UITableView) -> [String]? {
return ["A", "B", "C"]
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return "A title for section: \(section)"
}
Try the following code:
class TableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "Cell")
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 9
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return 9
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
// Configure the cell...
cell.textLabel?.text = "\(indexPath.section+1)\(indexPath.row+1)"
return cell
}
override func sectionIndexTitlesForTableView(tableView: UITableView) -> [String]? {
return ["A", "C", "B"]
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return "SECTION \(section+1)"
}
}

Answer 2

One way to do this is using built-in properties on the NSFetchedResultsController. The most important part of this is setting up the sectionNameKeyPath (which should be the managed object attribute holding the title).
private var frc: NSFetchedResultsController? = nil
private lazy var fetchedResultsController:NSFetchedResultsController = {
if self.frc != nil {
return self.frc!
}
//grab your managed object context
let moc = dbStore.sharedInstance.managedObjectContext
let fetchRequest = NSFetchRequest(entityName: "Transaction")
fetchRequest.fetchBatchSize = 30
fetchRequest.resultType = NSFetchRequestResultType.ManagedObjectResultType
let sortDescriptorByTimeStamp = NSSortDescriptor(key: "timeStamp", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptorByTimeStamp]
//in-memory cache when cachename is nil, delegate is non-nil
//note the sectionNameKeyPath requires that I have a related category object with the categoryName attribute on my Transaction managed object
let nfrc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc, sectionNameKeyPath: "category.categoryName", cacheName: nil)
self.frc = nfrc
do
{
try self.frc!.performFetch()
} catch let e as NSError {
fatalError(e.localizedDescription)
}
return self.frc!
}()
Section Titles
To get the section titles you implement this method.
func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
let sectionTitle = self.fetchedResultsController.sections?[section].name ?? "No Category Titles"
return sectionTitle
}
Table Index
To setup the index you implement the following method.
func sectionIndexTitlesForTableView(tableView: UITableView) -> [String]? {
return self.fetchedResultsController.sectionIndexTitles ?? [""]
}
Note the Quick Help Documentation when you click on
sectionIndexTitles. The array of section index titles. The default
implementation returns the array created by calling
sectionIndexTitleForSectionName: on all the known sections. You should
override this method if you want to return a different array for the
section index. You only need this method if you use a section index.
Source
If you want to see this in context, to get the gist of how to use the NSFetchedResultsController in this way you can checkout my sample at this location.
Alternates (Arrays/Dictionaries)
There are a few other tutorials about how to build an index from arrays and dictionaries (but I recommend the method above as simplest way to proceed).
Alternate Tutorial #1
Alternate Tutorial #2
Alternate Implementation
Note: Code in this section is from Alternate Tutorial #1
// `UIKit` convenience class for sectioning a table
let collation = UILocalizedIndexedCollation.currentCollation()
as UILocalizedIndexedCollation
....
/* section headers
appear above each `UITableView` section */
override func tableView(tableView: UITableView,
titleForHeaderInSection section: Int)
-> String {
// do not display empty `Section`s
if !self.sections[section].users.isEmpty {
return self.collation.sectionTitles[section] as String
}
return ""
}
/* section index titles
displayed to the right of the `UITableView` */
override func sectionIndexTitlesForTableView(tableView: UITableView)
-> [AnyObject] {
return self.collation.sectionIndexTitles
}
override func tableView(tableView: UITableView,
sectionForSectionIndexTitle title: String,
atIndex index: Int)
-> Int {
return self.collation.sectionForSectionIndexTitleAtIndex(index)
}