对于尝试使用Realm开发简单笔记应用程序的iOS，我相对较新。我有几个视图控制器。
创建新笔记：
//
// ViewController.swift
// Note It
//
// Created by James Parsons on 2/19/16.
// Copyright © 2016 James Parsons. All rights reserved.
//
import UIKit
import RealmSwift
import Realm
class NewNoteViewController: UIViewController {
// MARK: - Properties
var save: Bool?
var realm: Realm?
// MARK: - Outlets
@IBOutlet weak var txtView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
// Initialize realm.
realm = try! Realm()
// Set up insets.
txtView.contentInset = UIEdgeInsetsMake(-50, 10, 0, 0)
// Do we have any data from the last time?
let data: String? = NSUserDefaults.standardUserDefaults().objectForKey("lastNoteData") as? String
if (data != nil) {
txtView.text = data
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func viewWillDisappear(animated: Bool) {
// Do we want to save the data?
if save! {
if txtView.hasText() {
// Save the current note data
let noteData = txtView.text
NSUserDefaults.standardUserDefaults().setValue(noteData, forKey: "lastNoteData")
}
} else {
// No need to save note data. Clear the setting.
NSUserDefaults.standardUserDefaults().setValue(nil, forKey: "lastNoteData")
}
}
// MARK: - Actions
@IBAction func btnCancel(sender: UIBarButtonItem) {
// Save note content
save = true
self.navigationController!.presentingViewController?.dismissViewControllerAnimated(true, completion: nil)
}
@IBAction func btnSave(sender: UIBarButtonItem) {
var alert: UIAlertController
if txtView.hasText() {
let textToSerialize = txtView.text
alert = UIAlertController(title: "Save", message: "Enter a name for this note", preferredStyle: .Alert)
let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
let saveAction = UIAlertAction(title: "Save", style: .Default, handler: { (action: UIAlertAction) -> Void in
// DEBUG: See if this is firing.
// By the way it works.
print("Yay, it worked")
// Don't serialize data.
self.save = false
// Get the note name.
let name = alert.textFields!.first!.text!
// Build the note.
let noteToSave = Note(name: name, content: textToSerialize, date: NSDate())
// Save the note into Realm.
dispatch_async(dispatch_get_main_queue(), { () -> Void in
try! self.realm!.write {
self.realm!.add(noteToSave)
}
})
// Go back.
self.navigationController!.presentingViewController!.dismissViewControllerAnimated(true, completion: nil)
})
alert.addTextFieldWithConfigurationHandler {
(textField: UITextField) -> Void in
}
alert.addAction(cancelAction)
alert.addAction(saveAction)
presentViewController(alert, animated: true, completion: nil)
} else {
// Notes cannot be blank.
let alert = UIAlertController(title: "Whoops", message: "This note needs some content", preferredStyle: .Alert)
let okAction = UIAlertAction(title: "Ok", style: .Default, handler: nil)
alert.addAction(okAction)
// Show the alert.
presentViewController(alert, animated: true, completion: nil)
}
}
}
主视图：
//
// NotesViewController.swift
// Note It
//
// Created by James Parsons on 2/19/16.
// Copyright © 2016 James Parsons. All rights reserved.
//
import UIKit
import RealmSwift
import Realm
class NotesViewController: UITableViewController {
// MARK: - Properties
var notes: Results<Note>?
var realm: Realm?
// MARK: ViewController methods.
override func viewDidLoad() {
super.viewDidLoad()
// Refresh the table.
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.tableView.reloadData()
})
// Set up our Realm.
realm = try! Realm()
// Get all the notes.
notes = realm!.objects(Note)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Return number of objects.
return realm!.objects(Note).count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("note", forIndexPath: indexPath)
// Set up the cell with our data
if let note = notes?[indexPath.row] {
cell.textLabel!.text = note.name
cell.detailTextLabel!.text = dateToString(note.dateCreated)
}
return cell
}
/*
// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return true
}
*/
/*
// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
// Delete the row from the data source
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
} else if editingStyle == .Insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
override func tableView(tableView: UITableView, moveRowAtIndexPath fromIndexPath: NSIndexPath, toIndexPath: NSIndexPath) {
}
*/
/*
// Override to support conditional rearranging of the table view.
override func tableView(tableView: UITableView, canMoveRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return false if you do not want the item to be re-orderable.
return true
}
*/
// MARK: - Functions
func dateToString(date: NSDate) -> String {
let formatter = NSDateFormatter()
formatter.dateStyle = .ShortStyle
return formatter.stringFromDate(date)
}
}
和模型
//
// Note.swift
// Note It
//
// Created by James Parsons on 2/19/16.
// Copyright © 2016 James Parsons. All rights reserved.
//
import Foundation
import RealmSwift
// Realm model for notes.
class Note: Object {
// MARK: - Properties
dynamic var name = ""
dynamic var content = ""
dynamic var dateCreated = NSDate()
// MARK: - Intializers
required init() {
super.init()
}
required init(name: String, content: String, date: NSDate) {
self.name = name
self.content = content
self.dateCreated = date
super.init()
}
}
我知道保存操作的处理程序触发，但表中没有显示任何数据。我做错了什么？
答案 0 :(得分：1)
您需要的代码会在您添加注释时告知您的tableview更新。有许多方法可以解决这个问题。
一种可能的方法是使用领域通知功能。
首先将以下变量添加到NotesViewController：
var token: NotificationToken?
在NotesViewController的viewDidLoad中添加：
// Get all the notes.
notes = realm!.objects(Note)
token = notes!.addNotificationBlock({ (notification, realm) -> Void in
self.tableView.reloadData()
})
我对领域并不完全熟悉，但您可能还需要添加一个删除此标记的deinit实现：
deinit {
if let t = token {
t.stop()
}
}
编辑考虑到bdash的评论