Deleteするとクラッシュしてしまう。

Question

前提・実現したいこと

タスク管理するアプリを例にRealmの勉強しています。
Deleteをする際の通知機能の実装をしているのですが、Deleteをするとアプリがクラッシュしてしまう。
原因はどのように調べることができますか？
原因の調べ方とその原因を知りたいです。
Thread 1: signal SIGABRTがAppDelegate.swiftに表示されるのはOutletが繋がっていないということであっていますか？

回答よろしくおねがいします。

発生している問題・エラーメッセージ

AppDelegate.swift
Thread 1: signal SIGABRT

該当のソースコード

AppDelegate.swift

import UIKit
import UserNotifications

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        
        let center = UNUserNotificationCenter.current()
        center.requestAuthorization(options: [.alert, .sound]) { (granted, error) in
            // Enable or disable features based on authorization
        }
        
        center.delegate = self;
        
        return true
    }
    
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler([.sound, .alert])
    }

    func applicationWillResignActive(_ application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }

    func applicationWillTerminate(_ application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }


}

ViewController.swift

import UIKit
import RealmSwift
import UserNotifications

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    @IBOutlet weak var tableView: UITableView!
    
    let realm = try! Realm()
    
    var taskArray = try! Realm().objects(Task.self).sorted(byKeyPath: "date", ascending: false)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        tableView.delegate = self
        tableView.dataSource = self
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender:Any?) {
        let inputViewController:inputViewController = segue.destination as! inputViewController
        
        if segue.identifier == "cellSegue" {
            let indexPath = self.tableView.indexPathForSelectedRow
            inputViewController.task = taskArray[indexPath!.row]
        } else {
            let task = Task()
            task.date = Date()
            
            let allTasks = realm.objects(Task.self)
            if allTasks.count != 0 {
                task.id = allTasks.max(ofProperty: "id")! + 1
            }
            
            inputViewController.task = task
        }
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        tableView.reloadData()
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return taskArray.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        
        let task = taskArray[indexPath.row]
        cell.textLabel?.text = task.title
        
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd HH:mm"
        
        let dateString:String = formatter.string(from: task.date)
        cell.detailTextLabel?.text = dateString
        
        return cell
    }
    
    func tableView(_tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        performSegue(withIdentifier: "cellSegue", sender: nil)
    }
    
    func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath)-> UITableViewCellEditingStyle {
        return .delete
    }
    
    func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            
            let task = self.taskArray[indexPath.row]
            
            let center = UNUserNotificationCenter.current()
            center.removePendingNotificationRequests(withIdentifiers: [String(task.id)])
            
            try! realm.write {
                self.realm.delete(task)
                tableView.deleteRows(at: [indexPath], with: .fade)
            }
            
            center.getPendingNotificationRequests { (requests: [UNNotificationRequest]) in
                for request in requests {
                    print("/---------------")
                    print(request)
                    print("---------------/")
                }
            }
            
            try! realm.write {
                self.realm.delete(self.taskArray[indexPath.row])
                tableView.deleteRows(at: [indexPath], with: .fade)
            }
        }
    }

}

inputViewController.swift

import UIKit
import RealmSwift
import UserNotifications

class inputViewController: UIViewController {
    @IBOutlet weak var titleTextField: UITextField!
    @IBOutlet weak var contentsTextView: UITextView!
    @IBOutlet weak var datePicker: UIDatePicker!
    
    let realm = try! Realm()
    var task: Task!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        let tapGesture: UITapGestureRecognizer = UITapGestureRecognizer(target:self, action:#selector(dismissKeyboard))
        self.view.addGestureRecognizer(tapGesture)
        
        titleTextField.text = task.title
        contentsTextView.text = task.contents
        datePicker.date = task.date
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        try! realm.write {
            self.task.title = self.titleTextField.text!
            self.task.contents = self.contentsTextView.text
            self.task.date = self.datePicker.date
            self.realm.add(self.task, update: true)
        }
        
        setNotification(task: task)
        
        super.viewWillDisappear(animated)
    }
    
    func setNotification(task: Task) {
        let content = UNMutableNotificationContent()
        
        if task.title == "" {
            content.title = "(タイトルなし)"
        } else {
            content.title = task.title
        }
        if task.contents == "" {
            content.body = "(内容なし)"
        } else {
            content.body = task.contents
        }
        content.sound = UNNotificationSound.default()
        
        let calendar = Calendar.current
        let dateComponents = calendar.dateComponents([.year, .month, .day, .hour, .minute], from: task.date)
        let trigger = UNCalendarNotificationTrigger.init(dateMatching: dateComponents, repeats: false)
        
        let request = UNNotificationRequest.init(identifier: String(task.id), content: content, trigger: trigger)
        
        let center = UNUserNotificationCenter.current()
        center.add(request) { (error) in
            print(error ?? "ローカル通知登録 OK")
        }
        
        center.getPendingNotificationRequests { (requests: [UNNotificationRequest]) in
            for request in requests {
                print("/---------------")
                print(request)
                print("---------------/")
            }
        }
    }
    
    @objc func dismissKeyboard() {
        view.endEditing(true)
    }

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

Comments

[fuzzball]

Thread 1: signal SIGABRT はエラーメッセージではなく、「止まったよ」って言ってるだけです。
Consoleにエラーメッセージが表示されていないでしょうか？

Answer 1

原因の調べ方はfuzzballさんがおっしゃっているとおりです。

原因はほとんど予想ですが、
tableView.deleteRows(at: [indexPath], with: .fade)
の中でtableView側は、本当にソースデータが削除されているかを確認するために
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
を呼び出して（プログラマがミスをしていないか）確認しているようなのです。

今回でいえば、「アイテム数が何も変わっていないのでお前データソース削除しとらんやろ？」という意味で強制停止させられます。

というわけで、deleteRowsを呼び出す前にtaskArrayの要素を削除してください。

あとtableView.deleteRows(at: [indexPath], with: .fade)が二回行われそうな気がするので、
そこら辺がちゃんと意図した通りになっているのかも確認してください。

Comments

[ZY.]

ありがとうございます、解決できました。
`tableView.deleteRows(at: [indexPath], with: .fade)`が二回実行されていたようです。