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我創建了一個聯繫人應用程序，到目前爲止，我已經成功設法將項目保存到我的tableview。我有一個搜索欄，我想通過名字過濾掉我的單元格，我知道，因爲我在使用核心數據，我必須使用fetchResultsController和NSPredicate。我無法把這些東西全部弄清楚，也許有人可以幫助我？如何過濾我的核心數據中有對象的tableview？
另外這裏是我的核心數據實體，以防萬一。
實體：聯繫
屬性：
- 名字，字符串
- 姓氏，字符串
- 出生日期，字符串
- phoneNumber的，字符串
- 郵政編碼，字符串
我知道一些代碼可能不完整，但我只需要在何處採取這一方向。我只是想讓用戶輸入一個名字，它會按名字過濾單元格。讓我知道你是否需要更多信息。
現在，這裏是我ContactsTableVC代碼：
import UIKit
import CoreData
class ContactsTableVC: UITableViewController, UISearchBarDelegate, NSFetchedResultsControllerDelegate {
@IBOutlet weak var searchBar: UISearchBar!
var isFiltered: Bool = false
//Holds the core data model
var persons: [Person] = []
override func viewDidLoad() {
super.viewDidLoad()
searchBar.delegate = self
self.tableView.separatorStyle = UITableViewCellSeparatorStyle.none
self.tableView.backgroundColor = UIColor(red: 240/255.0, green: 240/255.0, blue: 240/255.0, alpha: 1.0)
fetch()
self.tableView.reloadData()
}
func getContext() -> NSManagedObjectContext {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
return appDelegate.persistentContainer.viewContext
}
// MARK: - Searchbar
//add fetchrequest to did ebgin editing
func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
}
func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
if(searchBar.text == "") {
isFiltered = false
} else {
isFiltered = true
}
}
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
filter(text: searchText)
}
// MARK: - Fetchresults controller/filtering data
func filter(text: String) {
//Create fetch request
let fetchRequest = NSFetchRequest<Person>()
// guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return } replaced with getcontext
// let managedObjectContext = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "Contact", in: getContext())
fetchRequest.entity = entity
let sortDescriptor = NSSortDescriptor(key: "firstName", ascending: false)
let sortDescriptors: [Any] = [sortDescriptor]
fetchRequest.sortDescriptors = sortDescriptors as? [NSSortDescriptor] ?? [NSSortDescriptor]()
if(text.characters.count > 0) {
let predicate = NSPredicate(format: "(firstName CONTAINS[c] %@)", text)
fetchRequest.predicate = predicate
}
let loadedEntities: [Person]? = try? getContext().fetch(fetchRequest)
filteredContacts = [Any](arrayLiteral: loadedEntities) as! [Person]
self.tableView.reloadData()
}
// MARK: - Data Source
func fetch() {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
let managedObjectContext = appDelegate.persistentContainer.viewContext
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName:"Contact")
do {
persons = try managedObjectContext.fetch(fetchRequest) as! [Person] //NSManagedObject
} catch let error as NSError {
print("Could not fetch. \(error)")
}
}
func save(firstName: String, lastName: String, dob: String, phoneNumber: String, zipCode: String) {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
let managedObjectContext = appDelegate.persistentContainer.viewContext
guard let entity = NSEntityDescription.entity(forEntityName:"Contact", in: managedObjectContext) else { return }
let person = NSManagedObject(entity: entity, insertInto: managedObjectContext)
person.setValue(firstName, forKey: "firstName")
person.setValue(lastName, forKey: "lastName")
person.setValue(dob, forKey: "dateOfBirth")
person.setValue(phoneNumber, forKey: "phoneNumber")
person.setValue(zipCode, forKey: "zipCode")
do {
try managedObjectContext.save()
self.persons.append(person as! Person) //previously just contact, no casting!
} catch let error as NSError {
print("Couldn't save. \(error)")
}
}
func update(indexPath: IndexPath, firstName: String, lastName: String, dob: String, phoneNumber: String, zipCode: String) {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
let managedObjectContext = appDelegate.persistentContainer.viewContext
let contact = persons[indexPath.row]
contact.setValue(firstName, forKey: "firstName")
contact.setValue(lastName, forKey: "lastName")
contact.setValue(dob, forKey: "dateOfBirth")
contact.setValue(phoneNumber, forKey: "phoneNumber")
contact.setValue(zipCode, forKey: "zipCode")
do {
try managedObjectContext.save()
persons[indexPath.row] = contact
} catch let error as NSError {
print("Couldn't update. \(error)")
}
}
func delete(_ contact: NSManagedObject, at indexPath: IndexPath) {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
let managedObjectContext = appDelegate.persistentContainer.viewContext
managedObjectContext.delete(contact)
persons.remove(at: indexPath.row)
//Always remember to save after deleting, updates Core Data
do {
try managedObjectContext.save()
} catch {
print("Something went wrong \(error.localizedDescription)")
}
}
// MARK: - Table View Setup
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return persons.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ContactCell", for: indexPath) as? PersonsCell
let person = persons[indexPath.row]
cell?.firstName?.text = person.value(forKey:"firstName") as? String
cell?.lastName?.text = person.value(forKey:"lastName") as? String
cell?.dob?.text = person.value(forKey:"dateOfBirth") as? String
cell?.phoneNumber?.text = person.value(forKey:"phoneNumber") as? String
cell?.zipCode?.text = person.value(forKey:"zipCode") as? String
return cell!
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 75
}
// Override to support conditional editing of the table view.
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
// MARK: - Navigation
@IBAction func unwindToContactsList(segue:UIStoryboardSegue) {
if let viewController = segue.source as? AddContactVC {
guard let _firstName: String = viewController.firstNameLbl.text,
let _lastName: String = viewController.lastNameLbl.text,
let _dob: String = viewController.dateOfBirthLbl.text,
let _phoneNumber: String = viewController.phoneNumberLbl.text,
let _zipCode: String = viewController.zipCodeLbl.text
else { return }
if _firstName != "" && _lastName != "" && _dob != "" && _phoneNumber != "" && _zipCode != "" {
if let indexPath = viewController.indexPathForContact {
update(indexPath: indexPath, firstName: _firstName, lastName: _lastName, dob: _dob, phoneNumber: _phoneNumber, zipCode: _zipCode)
print("Any updates?")
} else {
save(firstName: _firstName, lastName: _lastName, dob: _dob, phoneNumber: _phoneNumber, zipCode: _zipCode)
print("added to tableview") //this runs twice for some reason...
}
}
tableView.reloadData()
} else if let viewController = segue.source as? EditContactVC {
if viewController.isDeleted {
guard let indexPath: IndexPath = viewController.indexPath else { return }
let person = persons[indexPath.row]
delete(person, at: indexPath)
tableView.reloadData()
}
}
}
}