如何從CKRecord創建本地物件并將其附加到NSTableView資料的陣列

我正在為具有云功能的 macOS 開發一個筆記應用程式專案，特別是下載另一個人的筆記，給出筆記“CloudID”，這只是當筆記上傳到云時云資料庫給出的記錄的唯一名稱。我使用 sqlite 資料庫進行本地資料存盤，使用 cloudKit 資料庫進行公共資料存盤。當我測驗下載功能時，它會將資料正確地添加到 sqlite DB，但是我附加到我的 notesArray 的本地物件，該物件用于在我的主頁中填充 NSTableView 沒有被修改。

這是代碼：

@IBAction func downloadNoteFromCloud(_ sender: Any) {
    // 1.) check to make sure text field isn't empty
    if (noteIDTextField.stringValue == "") {
        noteIDTextField.stringValue = "Please enter the desired note's cloudID"
    }
    
    // 2.) query the note with the given cloudID
    
    // make note object for the downloaded note bc of scope issues
    var downloadedNote = Note(0, "", "")
    
    //sets cloudDB to the public cloud database
    let container = CKContainer.default()
    let cloudDB = container.publicCloudDatabase
    
    let noteRecordID = CKRecord.ID(recordName: noteIDTextField.stringValue)
    
    // returns a CKRecord
    cloudDB.fetch(withRecordID: noteRecordID) { record, error in
        if let error = error {
            // Handle error
            print(error)
            return
        }
        // Record fetched successfully
        if let noteRecord = record {
            // set the values of the downloadedNote obj equal the the values of the noteRecord
            downloadedNote.setValues((notesArray.count), noteRecord["Title"] as! String, noteRecord["Body"] as! String)
            
            // add to local database ~ this works
            do {
                let path = NSSearchPathForDirectoriesInDomains(
                    .applicationSupportDirectory, .userDomainMask, true
                ).first!   "/"   Bundle.main.bundleIdentifier!

                // create parent directory iff it doesn’t exist
                try FileManager.default.createDirectory(
                atPath: path, withIntermediateDirectories: true, attributes: nil
                )
                
                //connect to DB
                let db = try Connection("\(path)/db.sqlite3")
                //Define the Notes Table and its Columns
                let notes = Table("Notes")
                //ID is primary key so it doesn't need to be defined for inserts
                let title = Expression<String>("Title")
                let body = Expression<String>("Body")
                
                try db.run(notes.insert(title <- downloadedNote.title, body <- downloadedNote.body))
            }
            catch {
                print(error)
            }
        }
    }
    // append downloadedNote to notesArray
    notesArray.append(downloadedNote)
    
    //Send Notification to reload the tableView data
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "load"), object: nil)
    
    //Return to home page
    self.view.window?.close()
}

我假設這是一個范圍問題，我嘗試移動 append func，我嘗試將原始下載的note宣告設定為一個未像這樣初始化的可選型別：var downloadedNote: Note?然后在 fetch func 中對其進行初始化，例如所以：downloadedNote = Note(id: notesArray.count, title: noteRecord["Title"] as! String, body: noteRecord["Body"] as! String)沒有一個作業正常。我讓它最接近作業的是現在的代碼。請讓我知道我哪里出錯以及如何解決它。非常感謝您的幫助！

uj5u.com熱心網友回復：

CloudKit異步作業。移動代碼以通知并將表重新加載到閉包中

代替

           try db.run(notes.insert(title <- downloadedNote.title, body <- downloadedNote.body))
        }
        catch {
            print(error)
        }
    }
}
// append downloadedNote to notesArray
notesArray.append(downloadedNote)

//Send Notification to reload the tableView data
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "load"), object: nil)

//Return to home page
self.view.window?.close()

和

           try db.run(notes.insert(title <- downloadedNote.title, body <- downloadedNote.body))

           DispatchQueue.main.async {
               // append downloadedNote to notesArray
               notesArray.append(downloadedNote)

               //Send Notification to reload the tableView data
               NotificationCenter.default.post(name: NSNotification.Name(rawValue: "load"), object: nil)

               //Return to home page
               self.view.window?.close()
           }
        }
        catch {
            print(error)
        }
    }
}

并在閉包內創建新注釋。不再有范圍問題。

邊注：

NSSearchPathForDirectoriesInDomains聞起來很客觀，而且已經過時了。使用FileManagerURL 相關 API

do {
    let fm = FileManager.default
    let applicationSupportURL = try fm.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    let applicationSupportBundleURL = applicationSupportURL.appendingPathComponent(Bundle.main.bundleIdentifier!)
    
    if !fm.fileExists(atPath: applicationSupportBundleURL.path) {
        // create parent directory iff it doesn’t exist
        try fm.createDirectory(at: applicationSupportBundleURL, withIntermediateDirectories: true, attributes: nil)
    }
    let dbPath = applicationSupportBundleURL.appendingPathComponent("db.sqlite3").path
    
    //connect to DB
    let db = try Connection(dbPath)
    ...

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