ios - 如何在从 coredata 加载的 tableviewcontroller 中搜索

Question

下面给出了我的 tableviewcontroller 的代码

import UIKit
import CoreData
class NotesListTableViewController: UITableViewController  {
    var managedObjectContext : NSManagedObjectContext!
    var entries: [NSManagedObject]!

    override func viewDidLoad()
    {
        super.viewDidLoad()
        let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        managedObjectContext = appDelegate.managedObjectContext
        // makes the searchbar stay in the current screen and not spill into the next screen
        //          definesPresentationContext = true

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem()
    }

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

    // MARK: - Table view data source
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.entries.count
    }

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int
    {
        return 1
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("NotesCell", forIndexPath: indexPath)    
        // Configure the cell...
        let entry1 = entries[indexPath.row]
        cell.textLabel?.text = entry1.valueForKey("entry_body") as? String            
        let imageData2 = entry1.valueForKey("entry_image") as? NSData

        if let imageData2 = imageData2
        {
            let myimage = UIImage(data:imageData2,scale:1.0)
            cell.imageView?.image = myimage
        }        
        return cell        
   }
   override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
       if segue.identifier! == "showNote"
       {
           let detailDisplay = segue.destinationViewController as! DetailDisplayViewController
           let selectedIndexPath = tableView.indexPathForSelectedRow!
           let entry = entries[selectedIndexPath.row]
           detailDisplay.entry = entry
       }
   }
   override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
       let entry1 = self.entries[indexPath.row]
       self.managedObjectContext.deleteObject(entry1)
       self.entries.removeAtIndex(indexPath.row)
       self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Automatic)
       do
       {
           try managedObjectContext.save()
       } catch  {
           print ("could not save the new entry ")
       }
   }
   override func viewWillAppear(animated: Bool) {
       super.viewWillAppear(animated)
       self.tabBarController?.tabBar.hidden = false
       self.fetchEntries()     
   }

   func fetchEntries()
   {
       let fetchRequest = NSFetchRequest(entityName:"Entry")
       do {
          let entryObjects = try managedObjectContext.executeFetchRequest(fetchRequest)
          self.entries = entryObjects as! [NSManagedObject]
       }catch let error as NSError
       {
           print ("could not save the new entry \(error.description) ")
       }
       tableView.reloadData()
   }

Answer 1

首先，在你的 View Controller 中实现这个协议(protocol):

class NotesListTableViewController: UITableViewController, UITableViewDataSource, UITableViewDelegate{

在你的类中声明一个 UISearchController:

let searchController = UISearchController(searchResultsController: nil)

在方法 viewDidLoad 中:

searchController.searchBar.placeholder = "Search..."
searchController.searchBar.backgroundColor = UIColor.clearColor()
searchController.searchBar.searchBarStyle = UISearchBarStyle.Minimal
searchController.searchBar.tintColor = UIColor.blueColor()

searchController.searchResultsUpdater = self
searchController.dimsBackgroundDuringPresentation = false
definesPresentationContext = true
tableView.tableHeaderView = searchController.searchBar

用这个扩展你的 View Controller :

extension YourViewController: UISearchBarDelegate {
// MARK: - UISearchBar Delegate
    func searchBar(searchBar: UISearchBar, selectedScopeButtonIndexDidChange selectedScope: Int) {
        fetchEntries(searchBar.text!)
    }
}

extension YourViewController: UISearchResultsUpdating {
// MARK: - UISearchResultsUpdating Delegate
    func updateSearchResultsForSearchController(searchController: UISearchController) {
        fetchEntries(searchController.searchBar.text!)
    }
}

在这一点上你需要创建一个过滤数组“条目”的函数，例如你可以这样做:

func fetchEntries(searchText: String) {
    //To do your filter based in a String
    tableView.reloadData()
}