是否启动应用程序时发出通知铃声（Xamarin.Forms）

Question

我正在使用依赖服务 DependencyService.Get<ISetAlarm>().SetAlarm(hour,min,"Diabetics App","Hello i remind you to take medicine"); ，它连接到我的AlarmReceiver和AlarmImplementation类， 问题是：

当我以任何形式放置Dependency Service代码时，通知仅在启动该表单时出现；当我放入onStart,onSleep方法时，通知仅在这种状态下出现，我如何使应用程序像真正的警报一样发出通知，何时启动或不启动？

另外：

AlarmReceiver类

using System;
using Android.App;
using Android.Content;
using Android.Media;
using Android.Support.V4.App;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Globalization;
using Android.Widget;
using Diabetes.localDB;
using Xamarin.Forms;

namespace Diabetes.Droid
{
    [BroadcastReceiver]
    [IntentFilter(new string[] { "android.intent.action.BOOT_COMPLETED" }, Priority = (int)IntentFilterPriority.LowPriority)]
    public class AlarmReceiver : BroadcastReceiver
    {

        public override void OnReceive(Context context, Intent intent)
        {
            if (intent.Action.Equals("android.intent.action.BOOT_COMPLETED"))
            {
            var message = intent.GetStringExtra("message");
            var title = intent.GetStringExtra("title");



            //Show toast here
            //Toast.MakeText(context, "Hello it's me ", ToastLength.Short).Show();
            var extras = intent.Extras;

            if (extras != null && !extras.IsEmpty)
            {
                NotificationManager manager_ = context.GetSystemService(Context.NotificationService) as NotificationManager;
                var notificationId = extras.GetInt("NotificationIdKey", -1);
                if (notificationId != -1)
                {
                    manager_.Cancel(notificationId);
                }
            }

            //Create intent for action 1 (TAKE)
            var actionIntent1 = new Intent();
            actionIntent1.SetAction("ARCHIVE");
            var pIntent1 = PendingIntent.GetBroadcast(context, 0, actionIntent1, PendingIntentFlags.CancelCurrent);

            //Create intent for action 2 (REPLY)
            var actionIntent2 = new Intent();
            actionIntent2.SetAction("REPLY");
            var pIntent2 = PendingIntent.GetBroadcast(context, 0, actionIntent2, PendingIntentFlags.CancelCurrent);

            Intent resultIntent = context.PackageManager.GetLaunchIntentForPackage(context.PackageName);

            var contentIntent = PendingIntent.GetActivity(context, 0, resultIntent, PendingIntentFlags.CancelCurrent);

            var pending = PendingIntent.GetActivity(context, 0,
                resultIntent,
                PendingIntentFlags.CancelCurrent);
            //seting an alarm
            MedicationDatabase db = new MedicationDatabase();
            var alarm_list = db.GetAlarmList();
            //Debug.WriteLine(" Time -- : "+ m.ToString());


            // Instantiate the Big Text style:
            Notification.BigTextStyle textStyle = new Notification.BigTextStyle();


            var builder =
                new Notification.Builder(context)
                                .AddAction(Resource.Drawable.tick_notify, "ARCHIVE", pIntent1)
                                .AddAction(Resource.Drawable.cancel_notify, "REPLY", pIntent2)
                                .SetSmallIcon(Resource.Drawable.ic_launcher)
                                .SetContentTitle("Diabetics Reminder")
                                .SetDefaults(NotificationDefaults.Sound)
                                .SetStyle(new Notification
                                .BigTextStyle()
                                .SetSummaryText("")
                                .SetBigContentTitle(title)
                                .BigText(message)
             ).SetDefaults(NotificationDefaults.All);

            builder.SetContentIntent(pending);

            var notification = builder.Build();


            var manager = NotificationManager.FromContext(context);
            manager.Notify(10010, notification);
        }
        }
    }

    [BroadcastReceiver]
    [IntentFilter(new string[] { "ARCHIVE", "REPLY" })]
    public class CustomActionReceiver : BroadcastReceiver
    {
        public override void OnReceive(Context context, Intent intent)
        {

            switch (intent.Action)
            {
                case "ARCHIVE":
                    try
                    {
                        MedicationDatabase db = new MedicationDatabase();
                        db.addtracktaken("true");
                        Toast.MakeText(context, "DOSAGE TAKEN", ToastLength.Short).Show();
                    }
                    catch (Exception e)
                    {
                        Debug.WriteLine(e.StackTrace);
                    }
                    break;
                case "REPLY":
                    try
                    {
                        Toast.MakeText(context, "ARCHIVE", ToastLength.Short).Show();
                        MedicationDatabase db = new MedicationDatabase();
                        db.addtrackmissed("true");
                        Toast.MakeText(context, "DOSAGE MISSED", ToastLength.Short).Show();
                    }
                    catch (Exception e)
                    {
                        Debug.WriteLine(e.StackTrace);
                    }
                    break;
            }

            var extras = intent.Extras;

            if (extras != null && !extras.IsEmpty)
            {
                NotificationManager manager = context.GetSystemService(Context.NotificationService) as NotificationManager;
                var notificationId = extras.GetInt("NotificationIdKey", -1);
                if (notificationId != -1)
                {
                    manager.Cancel(notificationId);
                }
            }
        }
    }
}

AlarmImplementation类

[assembly: Xamarin.Forms.Dependency(typeof(SetAlarmImplementation))]
namespace Diabetes.Droid
{
    public class SetAlarmImplementation : ISetAlarm
    {

        public void SetAlarm(int hour, int minute, string title, string message, string)
        {

            MedicationDatabase db = new MedicationDatabase();
            var alarm_list = db.GetAlarmList();
            //Debug.WriteLine(" Time -- : "+ m.ToString());




            Intent myintent = new Intent(Xamarin.Forms.Forms.Context, typeof(AlarmReceiver));
            myintent.PutExtra("message", message);
            myintent.PutExtra("title", title);
            PendingIntent pendingintent = PendingIntent.GetBroadcast(Xamarin.Forms.Forms.Context, 0, myintent, PendingIntentFlags.UpdateCurrent);

            Java.Util.Date date = new Java.Util.Date();
            Java.Util.Calendar cal = Java.Util.Calendar.Instance;
            cal.TimeInMillis = Java.Lang.JavaSystem.CurrentTimeMillis();
            cal.Set(Java.Util.CalendarField.HourOfDay, hour);
            cal.Set(Java.Util.CalendarField.Minute, minute);
            cal.Set(Java.Util.CalendarField.Second, 0);
            //  PendingIntent pendingIntent = PendingIntent.GetBroadcast(this, 0, alarmIntent, PendingIntentFlags.UpdateCurrent);
            AlarmManager alarmManager = Xamarin.Forms.Forms.Context.GetSystemService(Android.Content.Context.AlarmService) as AlarmManager;
            alarmManager.Set(AlarmType.RtcWakeup, cal.TimeInMillis, pendingintent);
        }
    }
}

编辑：

这是我的新更新

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Diabetes.localDB;
using Diabetes.Main;

namespace Diabetes.Droid
{
    [Activity(Label = "MainApplication")]
    public class MainApplication : Activity
    {
        ISetAlarm alarmService;
        MedicationDatabase db = new MedicationDatabase();

        public MainApplication(){

        }
        public MainApplication(IntPtr handle, JniHandleOwnership transer) : base(handle, transer)
        {
        }

        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            alarmService = new SetAlarmImplementation();
            //Get list of stored time from Sqlite
            var alarm_list = db.GetAlarmList();
            //Debug.WriteLine(" Time -- : "+ m.ToString());
            var message = "Hello Its I remind you to take insulin";
            var title = "Diabetics App";
            foreach (var list in alarm_list)
            {
                var hour = Int32.Parse(list.Substring(0, 2));
                var minute = Int32.Parse(list.Substring(3, 2));
                alarmService.SetAlarm(hour, minute, title,message);
                // Create your application here
            }
        }
    }
}

这是我所做的，但是现在当我设置没有通知的时间时，就好像我必须以某种方式使其触发。

我认为答案很接近，我需要更多指导。

编辑2：

签出My Sqlite DB类：

using System;
using System.Collections.Generic;
using System.Linq;
using SQLite.Net;
using Xamarin.Forms;

namespace Diabetes.localDB
{
    public class MedicationDatabase
    {
        private SQLiteConnection _connection;

        public MedicationDatabase()
        {

            _connection = DependencyService.Get<ISQLite>().GetConnection();
            _connection.CreateTable<Medication>();
            _connection.CreateTable<SetReminder>();
            // _connection.CreateTable<Track>();
            _connection.CreateTable<TrackMissed>();
            _connection.CreateTable<TrackTaken>();
            _connection.CreateTable<LoginModel>();


        }
        public void AddDetails(string username, string alarm_time, string units, string insulin_type, string unique_id, string status)
        {

            _connection.Query<Medication>("Insert into [Medication] (username, alarm_time, units,insulin_type,unique_id,status) values" +
                                          "('" + username + "','" + alarm_time + "','" + units + "','" + insulin_type + "','" + unique_id + "','" + status + "')");

        }


        public void AddReminder(string username, string alarm_time,
                             string units, string insulin_type, string count_times)
        {

            _connection.Query<SetReminder>("Insert into [SetReminder] (username, alarm_time, units,insulin_type,count_times) values" +
                                          "('" + username + "','" + alarm_time + "','" + units
                                           + "','" + insulin_type + "','" + count_times + "')");
        }

        public IEnumerable<Medication> AllMedicationResults()
        {
            return (from t in _connection.Table<Medication>()
                    select t).ToList();
        }

        public IEnumerable<SetReminder> AllReminders()
        {
            return (from t in _connection.Table<SetReminder>()
                    select t).ToList();
        }

        public IEnumerable<string> GetAlarmList()
        {
            return (from t in _connection.Table<Medication>()
                    select t.alarm_time).ToList();
        }


        /* public string AlarmSample(){
             return (_connection.Table<SetReminder>().Select(r => r.)
            .AsEnumerable()
                      .Select(r => r.Substring(1, r.Length - 2).Split(','))).ToList().ToString()
                                                                            ;        }*/

        public IEnumerable<string> GetUnitsList()
        {
            return (from t in _connection.Table<Medication>()
                    select t.units).ToList();
        }

        public void DeleteAlarm()
        {
            _connection.DeleteAll<SetReminder>();
        }


        public void DeleteTime(int id)
        {

            _connection.Delete<Medication>(id);
        }

        public void DeleteAllTime()
        {
            _connection.DeleteAll<Medication>();
        }

        // Tracking table 
        public void addtracktaken(string taken)
        {

            _connection.Query<TrackTaken>("Insert into [TrackTaken] (taken) values" +
                                          "('" + taken + "')");
        }

        public void addtrackmissed(string missed)
        {

            _connection.Query<TrackMissed>("Insert into [TrackMissed] (missed) values" +
                                           "('" + missed + "')");
        }

        public int GetTracksTakenNos()
        {
            return (from t in _connection.Table<TrackTaken>()
                    select t.taken).Count();
        }

        public int GetTracksMissedNo()
        {
            return (from t in _connection.Table<TrackMissed>()
                    select t.missed).Count();
        }

        //Loging in 
        public void addUser(string username, string logged)
        {

            _connection.Query<LoginModel>("Insert into [LoginModel] (username,LoggedIn) values" +
                                          "('" + username + "', '" + logged + "')");
        }

        public void DeleteUsers()
        {
            _connection.DeleteAll<LoginModel>();
        }

        public string LoggedInStatus()
        {
            List<LoginModel> list = _connection.Query<LoginModel>("Select LoggedIn From [LoginModel] where ID=1");
            return list[0].LoggedIn;

        }

        public string GetUserName()
        {
            List<LoginModel> list = _connection.Query<LoginModel>("Select username From [LoginModel] where ID=1");
            return list[0].username;

        }

    }
}

和接口：

namespace Diabetes.localDB
{
    public interface ISQLite
    {
        SQLiteConnection GetConnection();
    }
}

Answer 1

首先，不要使用DependencyService，因为它依赖于Xamarin Forms的初始化，因此它将在打开应用程序时起作用。 在应用程序关闭时，您无法执行任何与Xamarin Forms相关的调用，因为此时MainActivity不可用，并且Xamarin Forms在其上进行中继。

建议您执行以下操作：

1.创建一个Android Application类

2.在那里创建警报服务的实例。

3.设置闹钟

 [Application]
 public class MainApplication : Application
 {
     ISetAlarm alarmService;
     public MainApplication(IntPtr handle, JniHandleOwnership transer) :base(handle, transer)
     {
     }

     public override void OnCreate()
     {
        base.OnCreate();
        alarmService = new SetAlarmImplementation();
        alarmService.SetAlarm(hour,min,"Diabetics App","Hello i remind you to take medicine");

     }
}

Answer 2

在应用程序类的OnCreate方法上启动粘性服务，以便即使关闭应用程序，该服务也可以使应用程序保持活动状态，并且您仍然可以收到通知。

[Application]
public class MainApplication : Application
{
    public static Context AppContext;
    public MainApplication(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
    {
    }

    public override void OnCreate()
    {
        base.OnCreate();
        AppContext = this.ApplicationContext;

        StartService();
    }

    public static void StartService()
    {
        AppContext.StartService(new Intent(AppContext, typeof(AppStickyService)));
        if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Kitkat)
        {

            PendingIntent pintent = PendingIntent.GetService(AppContext, 0, new Intent(AppContext, typeof(AppStickyService)), 0);
            AlarmManager alarm = (AlarmManager)AppContext.GetSystemService(Context.AlarmService);
            alarm.Cancel(pintent);
        }
    }

    public static void StopService()
    {
        AppContext.StopService(new Intent(AppContext, typeof(AppStickyService)));
                    if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Kitkat)
        {
            PendingIntent pintent = PendingIntent.GetService(AppContext, 0, new Intent(AppContext, typeof(AppStickyService)), 0);
            AlarmManager alarm = (AlarmManager)AppContext.GetSystemService(Context.AlarmService);
            alarm.Cancel(pintent);
        }
    }

}

创建一个粘性服务类：

[Service]
public class AppStickyService : Service
{
    public override void OnCreate()
    {
        base.OnCreate();

        System.Diagnostics.Debug.WriteLine("Sticky Service - Created");
    }

    public override StartCommandResult OnStartCommand(Android.Content.Intent intent, StartCommandFlags flags, int startId)
    {
        System.Diagnostics.Debug.WriteLine("Sticky Service - Started");
        return StartCommandResult.Sticky;
    }

    public override Android.OS.IBinder OnBind(Android.Content.Intent intent)
    {
        System.Diagnostics.Debug.WriteLine("Sticky Service - Binded");
        return null;
    }

    public override void OnDestroy()
    {
        System.Diagnostics.Debug.WriteLine("Sticky Service - Destroyed");
        base.OnDestroy();
    }
}