Android Xamarin-使用SQLite时打开计划的通知会停止重复并崩溃 _Android

【Android Xamarin-使用SQLite时打开计划的通知会停止重复并崩溃】别裁伪体亲风雅，转益多师是汝师。这篇文章主要讲述Android Xamarin-使用SQLite时打开计划的通知会停止重复并崩溃相关的知识，希望能为你提供帮助。
我已经使用SQLite创建了一个具有6个数据库表的Xamarin android应用程序。我实现了重复通知功能，每次调用通知时，该功能都会显示与SQLite表不同的元素。这是通过使应用程序在后台运行并遍历SQL数据以找到要在通知中显示的元素来完成的。如果点击通知，则会打开应用程序，并且通知中显示的信息会显示在应用程序的页面上。
所以我可以做的就是打开我的应用程序并将其设置为显示重复通知。每次触发通知时，通知都会根据通过SQL数据的后台函数显示不同的信息。我退出我的应用程序并清除我最近的应用程序以使其在后台运行。通知和更改信息效果很好。但是，一旦我重新打开该应用程序，通知就会停止触发，稍后当我关闭我的应用程序时，我会收到通知，通知该应用程序已停止响应。
我相信问题来自Android警报服务和SQLite数据连接。即使再次打开应用程序后，如何保持通知不断重复？如果我在最初设置要显示的通知后再也没有打开应用程序，则通知将继续显示而不会出现错误。
这是我的课程，用于设置警报管理器并创建通知

[assembly: Dependency(typeof(LawsForImpact.Droid.AndroidNotificationManager))] namespace LawsForImpact.Droid { [BroadcastReceiver] public class AndroidNotificationManager : BroadcastReceiver, INotificationManager { const string channelId = "default"; const string channelName = "Default"; const string channelDescription = "The default channel for notifications."; const int pendingIntentId = 0; public const string LocalNotificationKey = "LocalNotification"; public const string TableKey = "table"; public const string IndexKey = "index"; bool channelInitialized = false; int messageId = -1; NotificationManager manager; public event EventHandler NotificationReceived; string currentTitle; int currentIndex; SavedInformation savedInfo; public void Initialize() { CreateNotificationChannel(); }public int ScheduleNotification(string title, string message) { if (!channelInitialized) { CreateNotificationChannel(); }messageId++; // 1 MainActivity intent allows MainActivity to change once notification tapped Intent intentMain = new Intent(AndroidApp.Context, typeof(MainActivity)); intentMain.PutExtra(TableKey, currentTitle); intentMain.PutExtra(IndexKey, currentIndex); PendingIntent pendingIntentMain = PendingIntent.GetActivity(AndroidApp.Context, pendingIntentId, intentMain, PendingIntentFlags.UpdateCurrent); NotificationCompat.BigTextStyle textStyle = new NotificationCompat.BigTextStyle(); NotificationCompat.Builder builder = new NotificationCompat.Builder(AndroidApp.Context, channelId) .SetContentIntent(pendingIntentMain) .SetContentTitle(title) .SetContentText(message) .SetLargeIcon(BitmapFactory.DecodeResource(AndroidApp.Context.Resources, Resource.Drawable.ic_mtrl_chip_checked_circle)) .SetSmallIcon(Resource.Drawable.ic_mtrl_chip_checked_black) .SetDefaults((int)NotificationDefaults.Sound | (int)NotificationDefaults.Vibrate) .SetStyle(textStyle); Random random = new Random(); int randomNumber = random.Next(9999 - 1000) + 1000; Notification notification = builder.Build(); manager.Notify(randomNumber, notification); return messageId; }public void SavedInfo(SerializableDictionary< string, int> pickedQueue, int queueIndex, bool randomTog, int repeatInterval) { savedInfo = new SavedInformation(); currentTitle = pickedQueue.ElementAt(queueIndex).Key; savedInfo.QueueOfSaved = pickedQueue; savedInfo.QueueIndex = queueIndex; savedInfo.RandomToggle = randomTog; savedInfo.RepeatInterval = repeatInterval; LoadData(); RepeatAlarmSet(); }public override void OnReceive(Context context, Intent intent) {var extra = intent.GetStringExtra(LocalNotificationKey); var notification = DeserializeNotification(extra); SerializableDictionary< string, int> queue = notification.QueueOfSaved; var queueIndex = notification.QueueIndex; var randTog = notification.RandomToggle; var repInterval = notification.RepeatInterval; SavedInfo(queue, queueIndex, randTog, repInterval); }public void RepeatAlarmSet() { Intent intent = new Intent(Application.Context, typeof(AndroidNotificationManager)); var serializedNotification = SerializeNotification(savedInfo); intent.PutExtra(LocalNotificationKey, serializedNotification); var pendingIntent = PendingIntent.GetBroadcast(Application.Context, 0, intent, PendingIntentFlags.UpdateCurrent); var alarmManager = GetAlarmManager(); alarmManager.SetExactAndAllowWhileIdle(AlarmType.RtcWakeup, 1000, pendingIntent); }public void Cancel() {var intent = new Intent(Application.Context, typeof(AndroidNotificationManager)); var pendingIntent = PendingIntent.GetBroadcast(Application.Context, 0, intent, PendingIntentFlags.UpdateCurrent); var alarmManager = GetAlarmManager(); pendingIntent.Cancel(); alarmManager.Cancel(pendingIntent); var notificationManager = NotificationManagerCompat.From(Application.Context); notificationManager.CancelAll(); }private async void LoadData() { SQLiteConnection _sqLiteConnection; _sqLiteConnection = await Xamarin.Forms.DependencyService.Get< ISQLite> ().GetConnection(); IEnumerable< IDataTable> tableToEnumerable = new List< IDataTable> (); List< IDataTable> listData; switch (currentTitle) { case "Table1": tableToEnumerable = _sqLiteConnection.Table< Table1> ().ToList(); break; case "Table2": tableToEnumerable = _sqLiteConnection.Table< Table2> ().ToList(); break; case "Table3": tableToEnumerable = _sqLiteConnection.Table< Table3> ().ToList(); break; case "Table4": tableToEnumerable = _sqLiteConnection.Table< Table4> ().ToList(); break; case "Table5": tableToEnumerable = _sqLiteConnection.Table< Table5> ().ToList(); break; case "Table6": tableToEnumerable = _sqLiteConnection.Table< Table6> ().ToList(); break; } listData = https://www.songbingjia.com/android/tableToEnumerable.ToList(); int index = listData.Count() - savedInfo.QueueOfSaved[currentTitle]; index = index - 1; currentIndex = index; // if random enabled if (savedInfo.RandomToggle) { Random random = new Random(); index = random.Next(0, listData.Count()); }//sets all the current notification information string title = listData[index].Title; string message = listData[index].Description; //logic for next notification// subtract the queue int of current notification subject to keep track of next index savedInfo.QueueOfSaved[currentTitle] = savedInfo.QueueOfSaved[currentTitle] - 1; // check for index overflow if (savedInfo.QueueOfSaved[currentTitle] < 0) { savedInfo.QueueOfSaved[currentTitle] = listData.Count() - 1; }// index of next table savedInfo.QueueIndex = savedInfo.QueueIndex + 1; // if next table index overflows that means its time to restart the table index and move up the notification index if (savedInfo.QueueIndex > = savedInfo.QueueOfSaved.Count) { savedInfo.QueueIndex = 0; }ScheduleNotification(title, message); }public void ReceiveNotification(string table, int index) { var args = new NotificationEventArgs() { Table = table, Index = index, }; NotificationReceived?.Invoke(null, args); var notificationManager = NotificationManagerCompat.From(Application.Context); notificationManager.CancelAll(); }public static Intent GetLauncherActivity() {var packageName = Application.Context.PackageName; return Application.Context.PackageManager.GetLaunchIntentForPackage(packageName); }void CreateNotificationChannel() { manager = (NotificationManager)AndroidApp.Context.GetSystemService(AndroidApp.NotificationService); if (Build.VERSION.SdkInt > = BuildVersionCodes.O) { var channelNamejava = new Java.Lang.String(channelName); var channel = new NotificationChannel(channelId, channelNameJava, NotificationImportance.Default) { Description = channelDescription }; manager.CreateNotificationChannel(channel); }channelInitialized = true; }private string SerializeNotification(SavedInformation notification) {var xmlSerializer = new XmlSerializer(notification.GetType()); using (var stringWriter = new StringWriter()) { xmlSerializer.Serialize(stringWriter, notification); return stringWriter.ToString(); } }private SavedInformation DeserializeNotification(string notificationString) {var xmlSerializer = new XmlSerializer(typeof(SavedInformation)); using (var stringReader = new StringReader(notificationString)) { var notification = (SavedInformation)xmlSerializer.Deserialize(stringReader); return notification; } }private AlarmManager GetAlarmManager() { var alarmManager = Application.Context.GetSystemService(Context.AlarmService) as AlarmManager; return alarmManager; } }

我相信MainActivity以某种方式参与其中，因为它负责重新启动应用程序的过程。

[Activity( LaunchMode = LaunchMode.SingleTop, Label = "LawsForImpact", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity {protected override void OnCreate(Bundle savedInstanceState) { TabLayoutResource = Resource.Layout.Tabbar; ToolbarResource = Resource.Layout.Toolbar; base.OnCreate(savedInstanceState); global::Xamarin.Forms.Forms.Init(this, savedInstanceState); LoadApplication(new App()); CreateNotificationFromIntent(Intent); }protected override void OnNewIntent(Intent intent) { CreateNotificationFromIntent(intent); }void CreateNotificationFromIntent(Intent intent) { if (intent?.Extras != null) { string tableKey = intent.Extras.GetString(AndroidNotificationManager.TableKey); int indexKey = intent.Extras.GetInt(AndroidNotificationManager.IndexKey); DependencyService.Get< INotificationManager> ().ReceiveNotification(tableKey, indexKey); } }public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults) { Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults); base.OnRequestPermissionsResult(requestCode, permissions, grantResults); } }

答案我在后台进程中加载??SQL数据时遇到的问题。依赖服务引起了该问题。我通过使用Android设备监控器工具并在以下工具的帮助下找到了答案：Xamarin Service and Forms Init