当应用程序被滑动关闭时，没有收到Xamarin Forms Android推送通知

Question

去年我在Xamarin Forms应用程序中配置了推送通知，本周我决定更新到新的SDK，在iOS上这是一帆风顺的，但在Android上我遇到了问题。

我试图在这里复制文档：https://docs.microsoft.com/en-us/azure/notification-hubs/xamarin-notification-hubs-push-notifications-android-gcm 并相信我是90%的方式，因为我的应用程序在前台和后台时会很乐意接收推送通知，但是我的应用程序在被滑动关闭（而不是强制关闭）时无法接收推送通知。我知道这是100%不是设备问题，因为我使用FirebaseService类测试了旧配置，并且它工作正常。我还在使用“数据”通知。

当发送推送通知时，我能够在设备日志中找到以下错误消息：“错误（6621）/AndroidRuntime:java.lang.NullPointerException:尝试调用接口方法'void com.microsoft.windowsazure.messaging.notificationhubs.NotifictionListener.onPushNotificationReceived（android.content.Context，com.microsoft.windowsazure.messaging.notificationhubs.NotifictionMessage）“在空对象引用上”

请参阅下面我的Mainactive类的代码。

[Activity(Label = "AndroidNotificationTest", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, LaunchMode = LaunchMode.SingleTop, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize)]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        internal static readonly string CHANNEL_ID = "my_notification_channel";

        protected override void OnCreate(Bundle savedInstanceState)
        {
            TabLayoutResource = Resource.Layout.Tabbar;
            ToolbarResource = Resource.Layout.Toolbar;

            base.OnCreate(savedInstanceState);

            // Listen for push notifications
            NotificationHub.SetListener(new AzureListener());

            // Start the SDK
            NotificationHub.Start(this.Application, Constants.NotificationHubName, Constants.ListenConnectionString);
            NotificationHub.AddTag("Developer");

            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            LoadApplication(new App());

            CreateNotificationChannel();
        }

        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);
        }

        void CreateNotificationChannel()
        {
            if (Build.VERSION.SdkInt < BuildVersionCodes.O)
                return;

            NotificationChannel channel = new NotificationChannel(CHANNEL_ID, "FCM Notifications", NotificationImportance.Default)
            {
                Description = "Firebase Cloud Messages appear in this channel"
            };

            NotificationManager notificationManager = (NotificationManager)GetSystemService(NotificationService);
            notificationManager.CreateNotificationChannel(channel);
        }
    }

    internal class AzureListener : Java.Lang.Object, INotificationListener
    {
        public void OnPushNotificationReceived(Context context, INotificationMessage message)
        {
            Console.WriteLine($"Message received with title {message.Title} and body {message.Body}");
        }
    }

和我的Android清单文件。

<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="com.package.appname">
    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="29" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <application android:label="AndroidNotificationTest.Android" android:theme="@style/MainTheme"></application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
</manifest>

我花了好几天的时间来研究这个问题，但我在现阶段还不明白问题出在哪里。

Answer 1

也许我的工作代码可以帮助你。

我在使用 AzureListener 类编写新文档之前编写了此代码，但它仍然有效。

Xamarin 表单：推送通知在 Android 7.1.2 上不起作用

        //if i want more than one notification ,different unique value in every call
    Random u = new Random ();

    if (Build.VERSION.SdkInt >= BuildVersionCodes.O) {

        string channelName = Resources.GetString (Resource.String.channel_name);

        NotificationCompat.Builder notificationBuilder;



             notificationBuilder = new NotificationCompat.Builder (this, channelName)
                    .SetContentTitle (title)
                    .SetSmallIcon (Resource.Drawable.ic_stat_g)
                    .SetContentText (messageBody)
                    .SetAutoCancel (true)
                    .SetContentIntent (pendingIntent);


        var notificationManager = GetSystemService (Context.NotificationService) as NotificationManager;


        NotificationChannel channel = new NotificationChannel (channelName, "notification channel", NotificationImportance.Default);
        notificationManager.CreateNotificationChannel (channel);

        notificationManager.Notify (u.Next(), notificationBuilder.Build ());


    } 
    else
    {

        NotificationCompat.Builder notificationBuilder;


             notificationBuilder = new NotificationCompat.Builder (this)
                .SetContentTitle (title)
                .SetSmallIcon (Resource.Drawable.ic_stat_g)
                .SetContentText (messageBody)
                .SetAutoCancel (true)
                .SetContentIntent (pendingIntent);


        var notificationManager = GetSystemService (Context.NotificationService) as NotificationManager;

        notificationManager.Notify (u.Next(), notificationBuilder.Build ());
    }