CODEWITHSUNDEEP
ioscore-dataswiftnsfetchrequest
Jason Rybka
Jason Rybka

Reputation: 175

Retrieve Random String from Core Data in Swift

I've searched for this answer but have come up empty handed. For some reason I'm drawing a blank on how to retrieve a random entry from a Core Data String attribute. I have everything else working - create, update, delete... but can't seem to get a handle on getting a random entry from the stack.

Feeling confused on this. Here is my code from my table view controller that mostly manages the core data.

import UIKit
import CoreData

class TaskManagerViewController: UITableViewController, NSFetchedResultsControllerDelegate {

    let managedObjectContext = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext

    var fetchedResultController: NSFetchedResultsController = NSFetchedResultsController()

    override func viewDidLoad() {
        super.viewDidLoad()

        fetchedResultController = getFetchedResultController()
        fetchedResultController.delegate = self
        fetchedResultController.performFetch(nil)
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
        if segue.identifier == "edit" {
            let cell = sender as UITableViewCell
            let indexPath = tableView.indexPathForCell(cell)
            let taskController:TaskDetailViewController = segue.destinationViewController as TaskDetailViewController
            let task:Tasks = fetchedResultController.objectAtIndexPath(indexPath!) as Tasks
            taskController.task = task
        }
    }


    func getFetchedResultController() -> NSFetchedResultsController {
        fetchedResultController = NSFetchedResultsController(fetchRequest: taskFetchRequest(), managedObjectContext: managedObjectContext!, sectionNameKeyPath: nil, cacheName: nil)
        return fetchedResultController
    }

    func taskFetchRequest() -> NSFetchRequest {
        let fetchRequest = NSFetchRequest(entityName: "Tasks")
        let sortDescriptor = NSSortDescriptor(key: "desc", ascending: true)
        fetchRequest.sortDescriptors = [sortDescriptor]
        return fetchRequest
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // #pragma mark - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        let numberOfSections = fetchedResultController.sections?.count
        return numberOfSections!
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let numberOfRowsInSection = fetchedResultController.sections?[section].numberOfObjects
        return numberOfRowsInSection!
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
            var cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
            let task = fetchedResultController.objectAtIndexPath(indexPath) as Tasks
            cell.textLabel.text = task.desc
            return cell
    }


    override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
        let managedObject:NSManagedObject = fetchedResultController.objectAtIndexPath(indexPath) as NSManagedObject
        managedObjectContext?.deleteObject(managedObject)
        managedObjectContext?.save(nil)
    }

    func controllerDidChangeContent(controller: NSFetchedResultsController!) {
        tableView.reloadData()
    }
}

Upvotes: 0

Views: 1058

Answers (2)

Jason Rybka
Jason Rybka

Reputation: 175

This is the code that ultimately delivered the results I was looking for:

(I'm new at stack overflow so not sure how to select correct answer here.)

func randomTask() -> Tasks {

        let count = UInt32(fetchedResultController.fetchedObjects!.count)
        let index = Int(arc4random_uniform(count))
        var results = fetchedResultController.fetchedObjects![index] as Tasks
        answerLabel.text = results.valueForKey("desc") as NSString
        return results
    }

Upvotes: 2

Paulw11
Paulw11

Reputation: 114975

func randomTask() -> Tasks {

   let count=UInt32(fetchedResultController.fetchedObjects!.count) 
   let index=Int(arc4random_uniform(count))
   return fetchedResultsController.fetchedObjects[index] as Tasks
}

Upvotes: 2

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