我只做兼职的Android开发（考虑到API的许多细微之处和低级性，这似乎很有挑战性），并且在我的应用程序处于后台时无法接收通知。我的目标是Android 8.1。我的应用程序恰好使用Azure和Xamarin，但我不知道这些细节是否是问题的固有内容。
如果我的应用程序在后台运行，有时会显示通知，而其他时候我的应用程序因该错误而崩溃：
2019-03-06 09:12:24.486 9495-9702/? D/tyresense.azurelistenerservice: OnMessage() done
2019-03-06 09:12:28.278 1548-3232/? W/ActivityManager: Background start not allowed: service Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=com.rimex.tyresense cmp=com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.AzureListenerService (has extras) } to com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.AzureListenerService from pid=9495 uid=10173 pkg=com.rimex.tyresense
2019-03-06 09:12:28.341 9495-9495/? I/MonoDroid: Java.Lang.IllegalStateException: Not allowed to start service Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=com.rimex.tyresense cmp=com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.AzureListenerService (has extras) }: app is in background uid UidRecord{d582ba5 u0a173 RCVR bg:+1m0s848ms idle procs:1 seq(0,0,0)}
2019-03-06 09:12:28.342 9495-9495/? I/MonoDroid: java.lang.IllegalStateException: Not allowed to start service Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=com.rimex.tyresense cmp=com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.AzureListenerService (has extras) }: app is in background uid UidRecord{d582ba5 u0a173 RCVR bg:+1m0s848ms idle procs:1 seq(0,0,0)}
2019-03-06 09:12:28.347 9495-9495/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.rimex.tyresense, PID: 9495
java.lang.RuntimeException: Unable to start receiver md5bf34da605c12d097dc5a495af95e9376.TyreSenseBroadcastReceiver: java.lang.IllegalStateException: Not allowed to start service Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=com.rimex.tyresense cmp=com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.AzureListenerService (has extras) }: app is in background uid UidRecord{d582ba5 u0a173 RCVR bg:+1m0s848ms idle procs:1 seq(0,0,0)}
at android.app.ActivityThread.handleReceiver(ActivityThread.java:3285)
at android.app.ActivityThread.-wrap17(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1713)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6626)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:811)
Caused by: java.lang.IllegalStateException: Not allowed to start service Intent { act=com.google.android.c2dm.intent.RECEIVE flg=0x1000010 pkg=com.rimex.tyresense cmp=com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.AzureListenerService (has extras) }: app is in background uid UidRecord{d582ba5 u0a173 RCVR bg:+1m0s848ms idle procs:1 seq(0,0,0)}
at android.app.ContextImpl.startServiceCommon(ContextImpl.java:1536)
at android.app.ContextImpl.startService(ContextImpl.java:1492)
at android.content.ContextWrapper.startService(ContextWrapper.java:650)
at android.content.ContextWrapper.startService(ContextWrapper.java:650)
at md513d040a829b3f298fbeeee5a6e2c042a.GcmBroadcastReceiverBase_1.n_onReceive(Native Method)
at md513d040a829b3f298fbeeee5a6e2c042a.GcmBroadcastReceiverBase_1.onReceive(GcmBroadcastReceiverBase_1.java:29)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:3278)
at android.app.ActivityThread.-wrap17(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1713)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6626)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:811)
2019-03-06 09:12:28.348 2761-2761/? W/GCM: broadcast intent callback: result=CANCELLED forIntent { act=com.google.android.c2dm.intent.RECEIVE pkg=com.rimex.tyresense (has extras) }
2019-03-06 09:12:28.353 9495-9495/? E/tyresense.splashscreen: System.UnhandledExceptionEventArgs
2019-03-06 09:12:28.357 1548-7265/? W/ActivityManager: Force finishing activity com.rimex.tyresense/md5bf34da605c12d097dc5a495af95e9376.MainActivity
2019-03-06 09:12:28.363 1548-1632/? I/ActivityManager: Showing crash dialog for package com.rimex.tyresense u0
我看到这样的文章：https://blog.xamarin.com/replacing-services-jobs-android-oreo-8-0/
但是我不清楚问题究竟出在哪里，所以我不知道这是否可以解决。
也许在这里？
using System;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Util;
using Gcm.Client;
using WindowsAzure.Messaging;
using SharedMobile; // keep it simple, the app might not be running
using MyApp.Android; // we need to reference ourselves...
using Android.Support.V4.App;
using Android.Content.PM;
using System.Threading.Tasks;
[assembly: Permission(Name = "@PACKAGE_NAME@.permission.C2D_MESSAGE")]
[assembly: UsesPermission(Name = "@PACKAGE_NAME@.permission.C2D_MESSAGE")]
[assembly: UsesPermission(Name = "com.google.android.c2dm.permission.RECEIVE")]
[assembly: Xamarin.Forms.Dependency(typeof(DependencyListener))]
namespace MyApp.Android
{
[BroadcastReceiver(Permission = Constants.PERMISSION_GCM_INTENTS)]
[IntentFilter(new string[] { Constants.INTENT_FROM_GCM_MESSAGE }, Categories = new string[] { "@PACKAGE_NAME@" })]
[IntentFilter(new string[] { Constants.INTENT_FROM_GCM_REGISTRATION_CALLBACK }, Categories = new string[] { "@PACKAGE_NAME@" })]
[IntentFilter(new string[] { Constants.INTENT_FROM_GCM_LIBRARY_RETRY }, Categories = new string[] { "@PACKAGE_NAME@" })]
public class MyAppBroadcastReceiver : GcmBroadcastReceiverBase<AzureListenerService>
{
// this declaration somehow enables messages
}
[Service]
public class AzureListenerService : GcmServiceBase // this service might be started at system boot, when the app is otherwise not active
{
const string TAG = "MyApp.azurelistenerservice";
const string HUBNAME = "myhubname";
const string CONNECTION =
"Endpoint=sb://MyApp.servicebus.windows.net/;SharedAccessKeyName=DefaultListenSharedAccessSignature;SharedAccessKey=secretstuff...";
public const string GcmProjectNumber = "1234567890";
private static NotificationHub noteHub = null;
public AzureListenerService() : base(GcmProjectNumber)
{
}
// need client and area ids before this is called. Application.Context is not available if called from system boot
public static void InitializeAzure(Context context = null)
{
try
{
if (context == null)
context = Application.Context;
var enabled = NotificationManagerCompat.From(context).AreNotificationsEnabled();
SharedMobile.API.ApiService.Instance.NotificationsEnabled(enabled);
if (enabled)
{
GcmClient.CheckDevice(context);
GcmClient.CheckManifest(context);
GcmClient.Register(context, GcmProjectNumber);
}
}
catch (Exception ex)
{
Log.Error(TAG, ex.Message);
Messenger.SendException(ex.Message);
}
}
// incoming GCM registration
protected override void OnRegistered(Context context, string token)
{
try
{
noteHub = new NotificationHub(HUBNAME, CONNECTION, context);
var customerId = Int32.Parse(PropertyHelper.ClientId);
var tags = BuildTagList(customerId, PropertyHelper.AreaIds);
noteHub.Register(token, tags.ToArray());
Messenger.RegisterDevice(token);
}
catch (Exception ex)
{
Log.Error(TAG, "OnRegistered() " + ex.Message); // ignore register failure when using the Android emulator
}
}
protected override void OnMessage(Context context, Intent intent)
{
try
{
var areaIds = PropertyHelper.AreaIds;
if (string.IsNullOrWhiteSpace(areaIds)) // in case the user logged out
return;
new Notifications().CreateEventNotification(intent);
}
catch (Exception ex)
{
Log.Error(TAG, "OnMessage() " + ex.Message);
}
}
protected List<string> BuildTagList(int clientId, string areaIds)
{
var list = new List<string>();
list.Add($"client_{clientId}");
foreach (var id in areaIds.Split(','))
list.Add($"area_{id}");
return list;
}
protected override void OnUnRegistered(Context context, string registrationId)
{
Log.Error(TAG, "OnUnRegistered(): " + registrationId);
}
protected override bool OnRecoverableError(Context context, string errorId)
{
Log.Error(TAG, "OnRecoverableError(): " + errorId);
return base.OnRecoverableError(context, errorId);
}
protected override void OnError(Context context, string errorId)
{
Log.Error(TAG, "OnError(): " + errorId);
}
}
}
using System;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Support.V4.App;
using Android.Support.V4.Content;
using Android.Util;
using Exception = System.Exception;
namespace My.Android
{
internal class Notifications
{
const string TAG = "My.notifications";
const string TITLE = "Application is running";
const string DESC = "Tap to view";
const int MainProgramNotificationId = 775566;
// unique ID for our notification:
static readonly string CHANNEL_ID = "My_channel_23";
static readonly string CHANNEL_NAME = "[My_channel]";
internal void CreateProgramIcon_on_hold(Intent intent)
{
var extras = new Bundle();
extras.PutString("scopeDescription", TITLE);
extras.PutString("stateDescription", DESC);
intent.PutExtras(extras);
ShowNotification(intent.Extras, false);
}
internal void CreateEventNotification(Intent extra)
{
if (extra.Extras != null && !extra.Extras.IsEmpty)
ShowNotification(extra.Extras, true);
var notificationId = extra?.Extras?.GetString("notification-id", null);
if (notificationId != null && notificationId.Length > 0)
SharedMobile.API.ApiService.NotificationConfirmation(notificationId);
}
private void ShowNotification(Bundle extras, bool autoCancel)
{
try
{
string title = TITLE;
string description = DESC;
if (extras != null && !extras.IsEmpty)
{
title = extras.GetString("scopeDescription", null);
description = extras.GetString("stateDescription", "");
}
Intent intent = new Intent(Application.Context, typeof(SplashScreen));
BuildNotification(intent, extras, title, description, autoCancel);
}
catch (Exception ex)
{
Log.Debug(TAG, ex.Message);
}
}
private void BuildNotification(Intent intent, Bundle extras, string title, string description, bool autoCancel)
{
bool onGoing = !autoCancel;
int icon = IconId(null, null); // code not shown
intent.AddFlags(ActivityFlags.ReorderToFront);
var pendingIntent = PendingIntent.GetActivity(Application.Context, 0, intent, PendingIntentFlags.UpdateCurrent);
CreateNotificationChannel(autoCancel);
var notificationManager = Application.Context.GetSystemService(Context.NotificationService) as NotificationManager;
NotificationCompat.Builder builder = new NotificationCompat.Builder(Application.Context, CHANNEL_ID);
builder.SetSmallIcon(icon)
.SetContentTitle(title)
.SetContentText(description)
.SetSmallIcon(Resource.Drawable.notification_icon)
.SetAutoCancel(autoCancel)
.SetOngoing(onGoing)
.SetContentIntent(pendingIntent);
if (Build.VERSION.SdkInt >= BuildVersionCodes.Lollipop)
builder.SetColor(ContextCompat.GetColor(Application.Context, Resource.Color.exBackgroundColor));
string utcTicks = null;
if (extras != null)
utcTicks = extras.GetString("utcTicks", null);
if (utcTicks != null)
{
var ticks = Int64.Parse(utcTicks);
DateTimeOffset dto = new DateTimeOffset(ticks, TimeSpan.Zero);
builder.SetWhen(dto.ToUnixTimeMilliseconds());
}
else
builder.SetShowWhen(true);
notificationManager?.Notify(MainProgramNotificationId, builder.Build());
}
private void CreateNotificationChannel(bool evnt)
{
if (Build.VERSION.SdkInt < BuildVersionCodes.O)
{
// There is no need to create a notification channel on older versions of Android.
return;
}
NotificationImportance ni;
if (evnt)
ni = NotificationImportance.Default;
else
ni = NotificationImportance.Low;
var channel = new NotificationChannel(CHANNEL_ID, CHANNEL_NAME, ni)
{
Description = "My App",
LockscreenVisibility = NotificationVisibility.Private,
};
var notificationManager = Application.Context.GetSystemService(Context.NotificationService) as NotificationManager;
notificationManager.CreateNotificationChannel(channel);
}
string FormatTimeStamp(string utcTicks)
{
try
{
var ticks = Int64.Parse(utcTicks);
DateTimeOffset dto = new DateTimeOffset(ticks, TimeSpan.Zero);
return dto.ToLocalTime().ToString("MM/dd HH:mm:ss");
}
catch (Exception)
{
return string.Empty;
}
}
bool IgnoreActionProcess(string actionProcessId, int ackedProcessId)
{
try
{
if (int.Parse(actionProcessId) == ackedProcessId)
return true;
}
catch (Exception ex)
{
Log.Debug(TAG, $"int parse: {actionProcessId} {ex.Message}");
}
return false;
}
}
}
更新： 我将公共类AzureListenerService：GcmServiceBase中的OnMessage更改为不执行任何操作，但仍然崩溃：
未处理的异常： Java.Lang.IllegalStateException：不允许启动服务意图{act = com.google.android.c2dm.intent.RECEIVE flg = 0x1000010 pkg = com.mycompany.myapp cmp = com.mycompany.myapp / md5bf34da605c12d097dc5a495af95e9376.AzureListenerService（具有}}：应用程序处于后台uid UidRecord {d45626f u0a173 RCVR bg：+ 1m29s589ms空闲更改：未触发的进程：1 seq（0,0,0）}
更新 我实现了JobScheduler，这没有什么区别。而且，该应用程序必须在后台运行“一段时间”，然后问题总是会发生。我还更改了我的应用程序，使其在通知到达时什么也不做（除了日志），但仍然崩溃。
更新 我正在工作：https://developer.xamarin.com/samples/monodroid/Firebase/FCMNotifications/ 通过将其“按原样”添加到我的Firebase帐户中，下载google-services.json并使用http://pushtry.com/进行测试。 Azure门户测试还没有运气。如果我可以使Azure运行，希望将FCMNotifications中的代码合并到我的应用中。
答案 0 :(得分：3)
Android 8.0（API级别26）及更高版本对后台服务有限制。它包括对特定方法的以下更改：
现在，如果针对Android 8.0的应用尝试在不允许创建后台服务的情况下尝试使用该方法，则startService（）方法将引发IllegalStateException。 新的Context.startForegroundService（）方法启动前台服务。该系统允许应用程序在后台运行时调用Context.startForegroundService（）。但是，应用必须在创建服务后的五秒钟内调用该服务的startForeground（）方法。