今天开始学习Core Data，类似于数据库，可以永久保存数据。不过当把App从iPhone删掉之后就没有了。可以用来保存App的运行数据。
Part1:
//
// ViewController.swift
// Core Data Demo
//
// Created by zcdll on 16/1/22.
// Copyright © 2016年 ZC. All rights reserved.
// import UIKit
import CoreData class ViewController: UIViewController { override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib. let appDel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate let context: NSManagedObjectContext = appDel.managedObjectContext //第一次添加时使用，不注释会每次添加一次
/*
let newUser = NSEntityDescription.insertNewObjectForEntityForName("Users", inManagedObjectContext: context) newUser.setValue("zcdll", forKey: "username") newUser.setValue("asdf", forKey: "password") do { try context.save() } catch { print("Save problem") }
*/ let request = NSFetchRequest(entityName: "Users") do { let results = try context.executeFetchRequest(request) if results.count > 0 { for result in results as! [NSManagedObject] { print(result.valueForKey("username")!) print(result.valueForKey("password")!) } } } catch { print("Fetch failed") }
} override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Part2:
增加了更新数据，删除数据，查询数据等功能，感觉这样写很不灵活。
//
// ViewController.swift
// Core Data Demo
//
// Created by zcdll on 16/1/22.
// Copyright © 2016年 ZC. All rights reserved.
// import UIKit
import CoreData class ViewController: UIViewController { override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib. let appDel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate let context: NSManagedObjectContext = appDel.managedObjectContext //第一次添加时使用，不注释会每次添加一次
/*
let newUser = NSEntityDescription.insertNewObjectForEntityForName("Users", inManagedObjectContext: context) newUser.setValue("zcdll12", forKey: "username") newUser.setValue("asdf12", forKey: "password") do { try context.save() } catch { print("Save problem") }
*/ let request = NSFetchRequest(entityName: "Users") //request.predicate = NSPredicate(format: "username = %@", "zcdll3") request.returnsObjectsAsFaults = false do { let results = try context.executeFetchRequest(request) if results.count > 0 { for result in results as! [NSManagedObject] { /* context.deleteObject(result)
//result.setValue("zcdll3",forKey: "username") do { try context.save() } catch {} */ if let username = result.valueForKey("username") as? String { print(username) } //print(result.valueForKey("password")!) } } } catch { print("Fetch failed") }
} override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}