An example of using the NSFetchedResultsViewController in Swift 2.0

MNGNSFRVC.swift

//
//  MNGNSFRVC.swift
//  ProjectX
//
//  Created by Tommie N. Carter, Jr., MBA on 11/15/15.
//  Copyright © 2015 MING Technology. All rights reserved.
//

import UIKit
import CoreData

class MNGNSFRVC: UIViewController {
    
    deinit {
        
    }
    //MARK: Outlets
    @IBOutlet weak var tableView:UITableView! {
        didSet {
            tableView.tableFooterView = MNGStyleUtilities.sharedInstance.emptyView
        }
    }
    @IBOutlet weak var spendingReport: UILabel!
    @IBOutlet weak var communitySpendingTotal: UILabel!
    
    //MARK: Class Variables
    private var transactionTotal:Float = 0.0
    private var sectionTitles = [String]()
    private var frc: NSFetchedResultsController? = nil
    private lazy var fetchedResultsController:NSFetchedResultsController = {
        
        if self.frc != nil {
            return self.frc!
        }
        
        let moc = dbStore.sharedInstance.managedObjectContext
        
        
        let fetchRequest = NSFetchRequest(entityName: "Transaction")
        fetchRequest.fetchBatchSize = 30
        //let predicate = NSPredicate(format: "%K == %@", argumentArray: ["user", dbStore.sharedInstance.defaultUser])
        //fetchRequest.predicate = predicate
        fetchRequest.resultType = NSFetchRequestResultType.ManagedObjectResultType
        //storyFetchRequest.propertiesToFetch = ["assetURL","summary","title","tagsArray"]
        let sortDescriptorByTimeStamp =  NSSortDescriptor(key: "timeStamp", ascending: true)
        fetchRequest.sortDescriptors = [sortDescriptorByTimeStamp]
        
        //in-memory cache when cachename is nil, delegate is non-nil
        let nfrc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: moc, sectionNameKeyPath: "category.categoryName", cacheName: nil)
        
        //nfrc.delegate = self
        
        self.frc = nfrc
        do
        {
            try self.frc!.performFetch()
        } catch let e as NSError {
            //print(e.localizedDescription)
            fatalError(e.localizedDescription)
        }
        
        return self.frc!
    }()
    
    //MARK: View Lifecycle
    override func prefersStatusBarHidden() -> Bool {
        super.prefersStatusBarHidden()
        return true
    }
    override func viewDidLoad() {
        super.viewDidLoad()

    }
    override func viewWillAppear(animated: Bool) {
        super.viewWillDisappear(animated)
        refreshTransactionTotal()

    }
    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        
    }
    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        self.navigationItem.title = " Spend Summary "

    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    // MARK: Action Methods
    
    // MARK: Helper Methods
    func refreshTransactionTotal () {
        if self.fetchedResultsController.fetchedObjects?.count > 0 {
            transactionTotal = dbStore.sharedInstance.calculateTransactionSummary((self.fetchedResultsController.fetchedObjects as! [Transaction]))
            self.communitySpendingTotal.text = " Total:  \(transactionTotal)"
            
            
        }
    }
    // MARK: - Navigation
    
    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
    }
    @IBAction func unwindToSpend (segue:UIStoryboardSegue) {
        //refreshTransactionTotal()
        self.view.layoutIfNeeded()
        self.tableView.reloadData()
    }
    
}

//MARK:TableView & FetchedResultsController Methods
extension SpendViewController:UITableViewDelegate,UITableViewDataSource, NSFetchedResultsControllerDelegate {
    
    //MARK: TableView Sections
    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        
        print("# of sections: \(self.fetchedResultsController.sections?.count )")
        let count = self.fetchedResultsController.sections?.count ?? 1
        return count
    }
    
    func sectionIndexTitlesForTableView(tableView: UITableView) -> [String]? {
        
        return self.fetchedResultsController.sectionIndexTitles ?? [""]
        
    }
    //MARK: TableView Methods
    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        //
    }
    

 
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
       return self.fetchedResultsController.sections![section].numberOfObjects ?? 0
    }
    
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("TransactionCell", forIndexPath: indexPath) as! TransactionCell
        
        configure(cell, transaction: self.fetchedResultsController.objectAtIndexPath(indexPath) as! Transaction)
        
        // Configure the cell...
        
        return cell
    }
    func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        let sectionTitle = self.fetchedResultsController.sections?[section].name ?? "No Category Titles"
        return sectionTitle
        
    }
    func configure(cell:TransactionCell, transaction:Transaction) {
        
        //deal with imag e thumbnail for transaction
        //cell.imageView?.image
        
        cell.businessName.text =  transaction.business?.businessName ?? "No Business Added"
        
        cell.amount.text = transaction.amount?.stringValue ?? "0.00"
        
        cell.transactionDate.text = NSDateFormatter.localizedStringFromDate(transaction.transactionDate ?? NSDate(), dateStyle: NSDateFormatterStyle.ShortStyle, timeStyle: NSDateFormatterStyle.NoStyle)
        
        if let rating = transaction.rating?.userRating {
            cell.transactionRating.text = rating.stringValue
        }
        
        
        
    }
   
}