来自 CloudKit 的推送通知未正确同步
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【中文标题】来自 CloudKit 的推送通知未正确同步【英文标题】：Push Notification from CloudKit doesn't synchronize properly 【发布时间】：2016-05-14 05:37:08 【问题描述】：我正在尝试使用 iCloudKit 在 ios/Swift 中创建一个简单的聊天。我正在模仿这个例子：Create an App like Twitter: Push Notifications with CloudKit，但将其更改为聊天而不是 Sweets。
代码的横幅和徽章在一定程度上运行良好，将数据推送到 CloudDashboard 既好又快。
但从 cloudKit 到设备的同步大部分时间都不起作用。有时一个设备比另一个设备看到的更多，有时更少，只是不太可靠。我在 CloudKit 中使用 DEVELOPMENT 环境。
有什么问题？这是我在 appDelegate 和 viewController 中实现的方法的代码：
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool
// Override point for customization after application launch.
let notificationSettings = UIUserNotificationSettings(forTypes: [.Alert, .Badge, .Sound], categories: nil)
UIApplication.sharedApplication().registerUserNotificationSettings(notificationSettings)
UIApplication.sharedApplication().registerForRemoteNotifications()
return true
func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject])
let cloudKitNotification = CKNotification(fromRemoteNotificationDictionary: userInfo as! [String:NSObject])
if cloudKitNotification.notificationType == CKNotificationType.Query
dispatch_async(dispatch_get_main_queue(), () -> Void in
NSNotificationCenter.defaultCenter().postNotificationName("performReload", object: nil)
)
func resetBadge ()
let badgeReset = CKModifyBadgeOperation(badgeValue: 0)
badgeReset.modifyBadgeCompletionBlock = (error) -> Void in
if error == nil
UIApplication.sharedApplication().applicationIconBadgeNumber = 0
CKContainer.defaultContainer().addOperation(badgeReset)
func applicationWillResignActive(application: UIApplication)
func applicationDidEnterBackground(application: UIApplication)
resetBadge()
func applicationWillEnterForeground(application: UIApplication)
dispatch_async(dispatch_get_main_queue(), () -> Void in
NSNotificationCenter.defaultCenter().postNotificationName("performReload", object: nil)
)
func applicationDidBecomeActive(application: UIApplication)
resetBadge()
这是视图控制器
import UIKit
import CloudKit
class ChatViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UITextFieldDelegate
@IBOutlet weak var dockViewHeightConstraint: NSLayoutConstraint!
@IBOutlet weak var messageTextField: UITextField!
@IBOutlet weak var sendButton: UIButton!
@IBOutlet weak var messageTableView: UITableView!
var chatMessagesArray = [CKRecord]()
var messagesArray: [String] = [String]()
override func viewDidLoad()
super.viewDidLoad()
// Do any additional setup after loading the view.
self.messageTableView.delegate = self
self.messageTableView.dataSource = self
// set self as the delegate for the textfield
self.messageTextField.delegate = self
// add a tap gesture recognizer to the tableview
let tapGesture:UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(ChatViewController.tableViewTapped))
self.messageTableView.addGestureRecognizer(tapGesture)
setupCloudKitSubscription()
dispatch_async(dispatch_get_main_queue(), () -> Void in
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ChatViewController.retrieveMessages), name: "performReload", object: nil)
)
// retrieve messages form iCloud
self.retrieveMessages()
override func didReceiveMemoryWarning()
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
@IBAction func sendButtonTapped(sender: UIButton)
// Call the end editing method for the text field
self.messageTextField.endEditing(true)
// Disable the send button and textfield
self.messageTextField.enabled = false
self.sendButton.enabled = false
// create a cloud object
//var newMessageObject
// set the text key to the text of the messageTextField
// save the object
if messageTextField.text != ""
let newChat = CKRecord(recordType: "Chat")
newChat["content"] = messageTextField.text
newChat["user1"] = "john"
newChat["user2"] = "mark"
let publicData = CKContainer.defaultContainer().publicCloudDatabase
//TODO investigate if we want to do public or private
publicData.saveRecord(newChat, completionHandler: (record:CKRecord?, error:NSError?) in
if error == nil
dispatch_async(dispatch_get_main_queue(), () -> Void in
print("chat saved")
self.retrieveMessages()
)
)
dispatch_async(dispatch_get_main_queue())
// Enable the send button and textfield
self.messageTextField.enabled = true
self.sendButton.enabled = true
self.messageTextField.text = ""
func retrieveMessages()
print("inside retrieve messages")
// create a new cloud query
let publicData = CKContainer.defaultContainer().publicCloudDatabase
// TODO: we should use this
let predicate = NSPredicate(format: "user1 in %@ AND user2 in %@", ["john", "mark"], ["john", "mark"])
let query = CKQuery(recordType: "Chat", predicate: predicate)
//let query = CKQuery(recordType: "Chat", predicate: NSPredicate(format: "TRUEPREDICATE", argumentArray: nil))
query.sortDescriptors = [NSSortDescriptor(key:"creationDate", ascending: true)]
publicData.performQuery(query, inZoneWithID: nil) (results: [CKRecord]?, error:NSError?) in
if let chats = results
dispatch_async(dispatch_get_main_queue(), () -> Void in
self.chatMessagesArray = chats
print("count is: \(self.chatMessagesArray.count)")
self.messageTableView.reloadData()
)
func tableViewTapped ()
// Force the textfied to end editing
self.messageTextField.endEditing(true)
// MARK: TextField Delegate Methods
func textFieldDidBeginEditing(textField: UITextField)
// perform an animation to grow the dockview
self.view.layoutIfNeeded()
UIView.animateWithDuration(0.5, animations:
self.dockViewHeightConstraint.constant = 350
self.view.layoutIfNeeded()
, completion: nil)
func textFieldDidEndEditing(textField: UITextField)
// perform an animation to grow the dockview
self.view.layoutIfNeeded()
UIView.animateWithDuration(0.5, animations:
self.dockViewHeightConstraint.constant = 60
self.view.layoutIfNeeded()
, completion: nil)
// MARK: TableView Delegate Methods
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
// Create a table cell
let cell = self.messageTableView.dequeueReusableCellWithIdentifier("MessageCell")! as UITableViewCell
// customize the cell
let chat = self.chatMessagesArray[indexPath.row]
if let chatContent = chat["content"] as? String
let dateFormat = NSDateFormatter()
dateFormat.dateFormat = "MM/dd/yyyy"
let dateString = dateFormat.stringFromDate(chat.creationDate!)
cell.textLabel?.text = chatContent
//cell.detailTextLabel?.text = dateString
//cell.textLabel?.text = self.messagesArray[indexPath.row]
// return the cell
return cell
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
//print(tableView.frame.size)
//print("count: \(self.chatMessagesArray.count)")
return self.chatMessagesArray.count
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
*/
// MARK: Push Notifications
func setupCloudKitSubscription()
let userDefaults = NSUserDefaults.standardUserDefaults()
print("the value of the bool is: ")
print(userDefaults.boolForKey("subscribed"))
print("print is above")
if userDefaults.boolForKey("subscribed") == false // TODO: maybe here we do multiple types of subscriptions
let predicate = NSPredicate(format: "user1 in %@ AND user2 in %@", ["john", "mark"], ["john", "mark"])
//let predicate = NSPredicate(format: "TRUEPREDICATE", argumentArray: nil)
let subscription = CKSubscription(recordType: "Chat", predicate: predicate, options: CKSubscriptionOptions.FiresOnRecordCreation)
let notificationInfo = CKNotificationInfo()
notificationInfo.alertLocalizationKey = "New Chat"
notificationInfo.shouldBadge = true
subscription.notificationInfo = notificationInfo
let publicData = CKContainer.defaultContainer().publicCloudDatabase
publicData.saveSubscription(subscription) (subscription: CKSubscription?, error: NSError?) in
if error != nil
print(error?.localizedDescription)
else
userDefaults.setBool(true, forKey: "subscribed")
userDefaults.synchronize()
【问题讨论】：
【参考方案1】：我看到您正在使用推送通知作为重新加载所有数据的信号。 CloudKit 确实为特定谓词使用了兑现机制（详细信息未知）。在您的情况下，您一遍又一遍地执行相同的谓词。由于这种兑现，您可能会错过记录。尝试在大约一分钟后手动刷新，您会看到突然出现您的记录。
您应该以不同的方式处理推送通知。当您收到通知时，您还应该查询通知消息（当有多个通知时，您可能会收到 1 个推送通知。当您有很多通知时可能会发生这种情况）
但首先你应该处理当前的通知。首先检查通知是否用于查询：
if cloudKitNotification.notificationType == CKNotificationType.Query
然后使用以下命令将其转换为查询通知：
if let queryNotification = cloudNotification as? CKQueryNotification
获取记录ID
if let recordID = queryNotification.recordID
然后根据发生的情况更改您的本地（应用内）数据。您可以使用以下方法进行检查：
if queryNotification.queryNotificationReason == .RecordCreated
当然也可以。 RecordDeleted 或 .RecordUpdated
如果是.RecordCreated 或.RecordUpdated，您应该使用recordID 获取该记录
然后，当它被处理时，您必须获取其他未处理的通知。为此，您必须创建一个 CKFetchNotificationChangesOperation 您必须知道您必须向它传递一个更改令牌。如果您将其发送为零，您将获得为您的订阅创建的所有通知。操作完成后，它将向您发送一个新的更改令牌。您应该将其保存到您的 userDefaults 中，以便下次开始处理通知时可以使用它。
该查询的代码如下所示：
let operation = CKFetchNotificationChangesOperation(previousServerChangeToken: self.previousChangeToken)
operation.notificationChangedBlock = notification in
...
operation.fetchNotificationChangesCompletionBlock = changetoken, error in
...
operation.start()
然后对于该通知，您应该执行与上述初始通知相同的逻辑。并且更改令牌应该被保存。
这种机制的另一个好处是您的记录会一个一个地出现，您可以创建一个漂亮的动画来更新您的 tableview。
【讨论】：
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