Notifica non visualizzata in Oreo

Normal Notification Builder non mostra le notifiche su Android O.

Come posso mostrare la notifica su Android 8 Oreo?

C'è qualche nuovo pezzo di codice da aggiungere per mostrare la notifica su Android O?

In Android O è necessario utilizzare un canale con Notification Builder

di seguito è riportato un codice di esempio:

// Sets an ID for the notification, so it can be updated.
int notifyID = 1; 
String CHANNEL_ID = "my_channel_01";// The id of the channel. 
CharSequence name = getString(R.string.channel_name);// The user-visible name of the channel.
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);
// Create a notification and set the notification channel.
Notification notification = new Notification.Builder(MainActivity.this)
            .setContentTitle("New Message")
            .setContentText("You've received new messages.")
            .setSmallIcon(R.drawable.ic_notify_status)
            .setChannelId(CHANNEL_ID)
            .build();

O con compatibilità di gestione da:

NotificationCompat notification =
        new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("My notification")
        .setContentText("Hello World!")
        .setChannelId(CHANNEL_ID).build();



NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
 mNotificationManager.createNotificationChannel(mChannel);

// Issue the notification.
mNotificationManager.notify(notifyID , notification);

o se vuoi una soluzione semplice, usa il seguente codice:

NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
       mNotificationManager.createNotificationChannel(mChannel);
    }

Aggiornamenti: riferimento NotificationCompat.Builder

NotificationCompat.Builder(Context context)

Questo costruttore è stato deprecato nel livello API 26.0.0, quindi è necessario utilizzarlo

Builder(Context context, String channelId)

quindi non è necessario setChannelIdcon il nuovo costruttore.

E dovresti usare l'ultima libreria di AppCompat attualmente 26.0.2

compile "com.android.support:appcompat-v7:26.0.+"

Fonte dal canale degli sviluppatori Android su Youtube

Inoltre, puoi controllare i documenti Android ufficiali

Qui inserisco alcune funzioni di soluzione rapida con gestione degli intenti

public void showNotification(Context context, String title, String body, Intent intent) {
    NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

    int notificationId = 1;
    String channelId = "channel-01";
    String channelName = "Channel Name";
    int importance = NotificationManager.IMPORTANCE_HIGH;

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        NotificationChannel mChannel = new NotificationChannel(
                channelId, channelName, importance);
        notificationManager.createNotificationChannel(mChannel);
    }

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, channelId)
            .setSmallIcon(R.mipmap.ic_launcher)
            .setContentTitle(title)
            .setContentText(body);

    TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
    stackBuilder.addNextIntent(intent);
    PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(
            0,
            PendingIntent.FLAG_UPDATE_CURRENT
    );
    mBuilder.setContentIntent(resultPendingIntent);

    notificationManager.notify(notificationId, mBuilder.build());
}

Oltre a questa risposta , è necessario creare il canale di notifica prima che possa essere utilizzato.

  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

      /* Create or update. */
      NotificationChannel channel = new NotificationChannel("my_channel_01",
          "Channel human readable title", 
          NotificationManager.IMPORTANCE_DEFAULT);
      mNotificationManager.createNotificationChannel(channel);
  }

Inoltre è necessario utilizzare i canali solo se targetSdkVersion è 26 o superiore.

Se stai utilizzando NotificationCompat.Builder, devi anche aggiornare alla versione beta della libreria di supporto: https://developer.android.com/topic/libraries/support-library/revisions.html#26-0-0- beta2 (per poter chiamaresetChannelId il builder compat).

Fai attenzione poiché questo aggiornamento della libreria porta minSdkLevel a 14.

public class MyFirebaseMessagingServices extends FirebaseMessagingService {
    private NotificationChannel mChannel;
    private NotificationManager notifManager;
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        if (remoteMessage.getData().size() > 0) {
            try {
                JSONObject jsonObject = new JSONObject(remoteMessage.getData());
                displayCustomNotificationForOrders(jsonObject.getString("title"), jsonObject.getString("description"));
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }

    private void displayCustomNotificationForOrders(String title, String description) {
        if (notifManager == null) {
            notifManager = (NotificationManager) getSystemService
                    (Context.NOTIFICATION_SERVICE);
        }
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationCompat.Builder builder;
            Intent intent = new Intent(this, Dashboard.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            PendingIntent pendingIntent;
            int importance = NotificationManager.IMPORTANCE_HIGH;
            if (mChannel == null) {
                mChannel = new NotificationChannel
                        ("0", title, importance);
                mChannel.setDescription(description);
                mChannel.enableVibration(true);
                notifManager.createNotificationChannel(mChannel);
            }
            builder = new NotificationCompat.Builder(this, "0");

            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP |
                    Intent.FLAG_ACTIVITY_SINGLE_TOP);
            pendingIntent = PendingIntent.getActivity(this, 1251, intent, PendingIntent.FLAG_ONE_SHOT);
            builder.setContentTitle(title)  
                    .setSmallIcon(getNotificationIcon()) // required
                    .setContentText(description)  // required
                    .setDefaults(Notification.DEFAULT_ALL)
                    .setAutoCancel(true)
                    .setLargeIcon(BitmapFactory.decodeResource
                            (getResources(), R.mipmap.logo))
                    .setBadgeIconType(R.mipmap.logo)
                    .setContentIntent(pendingIntent)
                    .setSound(RingtoneManager.getDefaultUri
                            (RingtoneManager.TYPE_NOTIFICATION));
            Notification notification = builder.build();
            notifManager.notify(0, notification);
        } else {

            Intent intent = new Intent(this, Dashboard.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            PendingIntent pendingIntent = null;

            pendingIntent = PendingIntent.getActivity(this, 1251, intent, PendingIntent.FLAG_ONE_SHOT);

            Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
            NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                    .setContentTitle(title)
                    .setContentText(description)
                    .setAutoCancel(true)
                    .setColor(ContextCompat.getColor(getBaseContext(), R.color.colorPrimary))
                    .setSound(defaultSoundUri)
                    .setSmallIcon(getNotificationIcon())
                    .setContentIntent(pendingIntent)
                    .setStyle(new NotificationCompat.BigTextStyle().setBigContentTitle(title).bigText(description));

            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.notify(1251, notificationBuilder.build());
        }
    }

    private int getNotificationIcon() {
        boolean useWhiteIcon = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP);
        return useWhiteIcon ? R.mipmap.logo : R.mipmap.logo;
    }
}

Se non riesci a ricevere la notifica push nella versione SDK 26+?

la tua soluzione è qui:

public static void showNotification(Context context, String title, String messageBody) {

        boolean isLoggedIn = SessionManager.getInstance().isLoggedIn();
        Log.e(TAG, "User logged in state: " + isLoggedIn);

        Intent intent = null;
        if (isLoggedIn) {
            //goto notification screen
            intent = new Intent(context, MainActivity.class);
            intent.putExtra(Extras.EXTRA_JUMP_TO, DrawerItems.ITEM_NOTIFICATION);
        } else {
            //goto login screen
            intent = new Intent(context, LandingActivity.class);
        }

        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0 /* Request code */, intent, PendingIntent.FLAG_ONE_SHOT);

        //Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        //Bitmap largeIcon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_app_notification_icon);

        String channel_id = createNotificationChannel(context);

        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(context, channel_id)
                .setContentTitle(title)
                .setContentText(messageBody)
                .setStyle(new NotificationCompat.BigTextStyle().bigText(messageBody))
                /*.setLargeIcon(largeIcon)*/
                .setSmallIcon(R.drawable.app_logo_color) //needs white icon with transparent BG (For all platforms)
                .setColor(ContextCompat.getColor(context, R.color.colorPrimaryDark))
                .setVibrate(new long[]{1000, 1000})
                .setSound(Settings.System.DEFAULT_NOTIFICATION_URI)
                .setContentIntent(pendingIntent)
                .setPriority(Notification.PRIORITY_HIGH)
                .setAutoCancel(true);

        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify((int) ((new Date(System.currentTimeMillis()).getTime() / 1000L) % Integer.MAX_VALUE) /* ID of notification */, notificationBuilder.build());
    }

public static String createNotificationChannel(Context context) {

        // NotificationChannels are required for Notifications on O (API 26) and above.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

            // The id of the channel.
            String channelId = "Channel_id";

            // The user-visible name of the channel.
            CharSequence channelName = "Application_name";
            // The user-visible description of the channel.
            String channelDescription = "Application_name Alert";
            int channelImportance = NotificationManager.IMPORTANCE_DEFAULT;
            boolean channelEnableVibrate = true;
//            int channelLockscreenVisibility = Notification.;

            // Initializes NotificationChannel.
            NotificationChannel notificationChannel = new NotificationChannel(channelId, channelName, channelImportance);
            notificationChannel.setDescription(channelDescription);
            notificationChannel.enableVibration(channelEnableVibrate);
//            notificationChannel.setLockscreenVisibility(channelLockscreenVisibility);

            // Adds NotificationChannel to system. Attempting to create an existing notification
            // channel with its original values performs no operation, so it's safe to perform the
            // below sequence.
            NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
            assert notificationManager != null;
            notificationManager.createNotificationChannel(notificationChannel);

            return channelId;
        } else {
            // Returns null for pre-O (26) devices.
            return null;
        }
    }

NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder (context, channel_id)

-> Qui riceverai una notifica push utilizzando channel_idnel tuo dispositivo che è composto da 26+ versione SDK.

-> Perché NotificationCompat.Builder(context)ora il metodo è deprecato, utilizzerai una versione aggiornata con due parametri, uno è il contesto, l'altro è channel_id.

-> NotificationCompat.Builder(context, channel_id)metodo aggiornato. Provalo.

-> Nella versione 26+ dell'SDK del dispositivo creerai channel_id ogni volta.

Usa questa classe per le notifiche di Android 8

public class NotificationHelper {

private Context mContext;
private NotificationManager mNotificationManager;
private NotificationCompat.Builder mBuilder;
public static final String NOTIFICATION_CHANNEL_ID = "10001";

public NotificationHelper(Context context) {
    mContext = context;
}

/**
 * Create and push the notification 
 */
public void createNotification(String title, String message)
{    
    /**Creates an explicit intent for an Activity in your app**/
    Intent resultIntent = new Intent(mContext , SomeOtherActivity.class);
    resultIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

    PendingIntent resultPendingIntent = PendingIntent.getActivity(mContext,
            0 /* Request code */, resultIntent,
            PendingIntent.FLAG_UPDATE_CURRENT);

    mBuilder = new NotificationCompat.Builder(mContext);
    mBuilder.setSmallIcon(R.mipmap.ic_launcher);
    mBuilder.setContentTitle(title)
            .setContentText(message)
            .setAutoCancel(false)
            .setSound(Settings.System.DEFAULT_NOTIFICATION_URI)
            .setContentIntent(resultPendingIntent);

    mNotificationManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)
    {
        int importance = NotificationManager.IMPORTANCE_HIGH;
        NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "NOTIFICATION_CHANNEL_NAME", importance);
        notificationChannel.enableLights(true);
        notificationChannel.setLightColor(Color.RED);
        notificationChannel.enableVibration(true);
        notificationChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
        assert mNotificationManager != null;
        mBuilder.setChannelId(NOTIFICATION_CHANNEL_ID);
        mNotificationManager.createNotificationChannel(notificationChannel);
    }
    assert mNotificationManager != null;
    mNotificationManager.notify(0 /* Request Code */, mBuilder.build());
  }
}

Prova questo codice:

public class FirebaseMessagingServices extends com.google.firebase.messaging.FirebaseMessagingService {
    private static final String TAG = "MY Channel";
    Bitmap bitmap;

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
        Utility.printMessage(remoteMessage.getNotification().getBody());

        // Check if message contains a data payload.
        if (remoteMessage.getData().size() > 0) {
            Log.d(TAG, "Message data payload: " + remoteMessage.getData());

            String title = remoteMessage.getData().get("title");
            String body = remoteMessage.getData().get("body");
            String message = remoteMessage.getData().get("message");
            String imageUri = remoteMessage.getData().get("image");
            String msg_id = remoteMessage.getData().get("msg-id");
          

            Log.d(TAG, "1: " + title);
            Log.d(TAG, "2: " + body);
            Log.d(TAG, "3: " + message);
            Log.d(TAG, "4: " + imageUri);
          

            if (imageUri != null)
                bitmap = getBitmapfromUrl(imageUri);

            }

            sendNotification(message, bitmap, title, msg_id);
                    
        }


    }

    private void sendNotification(String message, Bitmap image, String title,String msg_id) {
        int notifyID = 0;
        try {
            notifyID = Integer.parseInt(msg_id);
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }

        String CHANNEL_ID = "my_channel_01";            // The id of the channel.
        Intent intent = new Intent(this, HomeActivity.class);
        intent.putExtra("title", title);
        intent.putExtra("message", message);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);


        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, "01")
                .setContentTitle(title)
                .setSmallIcon(R.mipmap.ic_notification)
                .setStyle(new NotificationCompat.BigTextStyle()
                        .bigText(message))
                .setContentText(message)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setChannelId(CHANNEL_ID)
                .setContentIntent(pendingIntent);

        if (image != null) {
            notificationBuilder.setStyle(new NotificationCompat.BigPictureStyle()   //Set the Image in Big picture Style with text.
                    .bigPicture(image)
                    .setSummaryText(message)
                    .bigLargeIcon(null));
        }


        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {       // For Oreo and greater than it, we required Notification Channel.
           CharSequence name = "My New Channel";                   // The user-visible name of the channel.
            int importance = NotificationManager.IMPORTANCE_HIGH;

            NotificationChannel channel = new NotificationChannel(CHANNEL_ID,name, importance); //Create Notification Channel
            notificationManager.createNotificationChannel(channel);
        }

        notificationManager.notify(notifyID /* ID of notification */, notificationBuilder.build());
    }

    public Bitmap getBitmapfromUrl(String imageUrl) {     //This method returns the Bitmap from Url;
        try {
            URL url = new URL(imageUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream input = connection.getInputStream();
            Bitmap bitmap = BitmapFactory.decodeStream(input);
            return bitmap;

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;

        }

    }

}

App demo di notifica Android per Android O e versioni API inferiori. Ecco la migliore app demo su GitHub-Demo 1 e GitHub-Demo 2 .

Questo è un bug in firebase api versione 11.8.0, quindi se riduci la versione dell'API non dovrai affrontare questo problema.

Stavo riscontrando lo stesso problema su Oreo e ho scoperto che se prima crei il tuo canale con NotificationManager.IMPORTANCE_NONE, quindi lo aggiorni in seguito, il canale manterrà il livello di importanza originale.

Questo è supportato dalla documentazione sulla formazione di Google Notification che afferma:

Dopo aver creato un canale di notifica, non è possibile modificare i comportamenti di notifica: l'utente ha il controllo completo a quel punto.

La rimozione e la reinstallazione dell'app ti consentiranno di ripristinare i comportamenti del canale.

È meglio evitare di utilizzare IMPORTANCE_NONE a meno che non si desideri sopprimere le notifiche per quel canale, ovvero utilizzare notifiche silenziose.

Ecco come lo fai

private fun sendNotification() {
    val notificationId = 100
    val chanelid = "chanelid"
    val intent = Intent(this, MainActivity::class.java)
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK)
    val pendingIntent = PendingIntent.getActivity(this, 0, intent, 0)
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { // you must create a notification channel for API 26 and Above
        val name = "my channel"
        val description = "channel description"
        val importance = NotificationManager.IMPORTANCE_DEFAULT
        val channel = NotificationChannel(chanelid, name, importance);
        channel.setDescription(description);
        // Register the channel with the system; you can't change the importance
        // or other notification behaviors after this
        val notificationManager = getSystemService(NotificationManager::class.java)
        notificationManager.createNotificationChannel(channel)
    }

    val mBuilder = NotificationCompat.Builder(this, chanelid)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle("Want to Open My App?")
            .setContentText("Open my app and see good things")
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setContentIntent(pendingIntent)
            .setAutoCancel(true) // cancel the notification when clicked
            .addAction(R.drawable.ic_check, "YES", pendingIntent) //add a btn to the Notification with a corresponding intent

    val notificationManager = NotificationManagerCompat.from(this);
    notificationManager.notify(notificationId, mBuilder.build());
}

Leggi il tutorial completo su => https://developer.android.com/training/notify-user/build-notification

CHANNEL_IDin NotificationChannel e Notification.Builder deve essere lo stesso, prova questo codice:

String CHANNEL_ID = "my_channel_01";
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, "Solveta Unread", NotificationManager.IMPORTANCE_DEFAULT);


Notification.Builder notification = new Notification.Builder(getApplicationContext(), CHANNEL_ID);

Bene, nel mio caso, ho Android 8.1.0 e numero di modello vivo1811 , e ho provato con tutte le soluzioni di cui sopra, ma niente funziona.

Quindi alla fine, ho scritto al supporto Firebase, quindi su un ulteriore debug, stavo ottenendo questo: "Impossibile trasmettere all'app arrestata": Assicurarsi che l'app non sia stata arrestata forzatamente " .

E questa è stata la risposta del team di Firebase ->

Questo è un problema noto causato da un'ottimizzazione della batteria implementata da alcuni OEM. Quando un'app viene trascinata via nel selettore di app, l'applicazione viene trattata come se fosse stata arrestata forzatamente, che non è il comportamento Android predefinito. Lo sfortunato effetto collaterale di questo è che può causare l'interruzione del servizio FCM per la tua app. Stiamo lavorando per migliorare questo comportamento da parte nostra, ma la soluzione effettiva deve provenire dal lato OEM.

Qui OEM sta per Original Equipment Manufacturer .

Per chiunque abbia problemi con questo dopo aver provato le soluzioni di cui sopra, assicurarsi che l'id del canale utilizzato durante la creazione del canale di notifica sia identico all'ID del canale impostato nel Generatore di notifiche.

const val CHANNEL_ID = "EXAMPLE_CHANNEL_ID"

// create notification channel
val notificationChannel = NotificationChannel(CHANNEL_ID, 
NOTIFICATION_NAME, NotificationManager.IMPORTANCE_HIGH)

// building notification
NotificationCompat.Builder(context)
                    .setSmallIcon(android.R.drawable.ic_input_add)
                    .setContentTitle("Title")
                    .setContentText("Subtitle")   
                    .setPriority(NotificationCompat.PRIORITY_MAX)
                    .setChannelId(CHANNEL_ID)

private void addNotification() {
                NotificationCompat.Builder builder =
                new NotificationCompat.Builder(this)
                .setSmallIcon(R.drawable.ic_launcher_background)
                .setContentTitle("Notifications Example")
                .setContentText("This is a test notification");
                Intent notificationIntent = new Intent(this, MainActivity.class);
                PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent,
                PendingIntent.FLAG_UPDATE_CURRENT);
                builder.setContentIntent(contentIntent);
                // Add as notification
                NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
                if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)
                {
                NotificationChannel nChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "NOTIFICATION_CHANNEL_NAME", NotificationManager.IMPORTANCE_HIGH);
                nChannel.enableLights(true);
                assert manager != null;
                builder.setChannelId(NOTIFICATION_CHANNEL_ID);
                manager.createNotificationChannel(nChannel);
                }
                assert manager != null;
                manager.notify(0, builder.build());
    }

Il seguente metodo mostrerà la notifica , con testo grande e blocco abilitati (la notifica non verrà rimossa anche dopo lo scorrimento dell'utente). Abbiamo bisogno del servizio NotificationManager

public static void showNotificationOngoing(Context context,String title) {
        NotificationManager notificationManager =
                (NotificationManager) context.getSystemService(NOTIFICATION_SERVICE);

        PendingIntent contentIntent = PendingIntent.getActivity(context, 0,
                new Intent(context, MainActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);

        Notification.Builder notificationBuilder = new Notification.Builder(context)
                .setContentTitle(title + DateFormat.getDateTimeInstance().format(new Date()) + ":" + accuracy)
                .setContentText(addressFragments.toString())
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentIntent(contentIntent)
                .setOngoing(true)
                .setStyle(new Notification.BigTextStyle().bigText(addressFragments.toString()))
                .setAutoCancel(true);
        notificationManager.notify(3, notificationBuilder.build());
}

Metodo per rimuovere le notifiche

public static void removeNotification(Context context){
    NotificationManager notificationManager =
            (NotificationManager) context.getSystemService(NOTIFICATION_SERVICE);
    notificationManager.cancelAll();
}

Link alla fonte

NotificationCompat.Builder(Context context)

già deprecato per la versione maggiore o uguale Android Oreo. È possibile modificare l'implementazione in utilizzo

NotificationCompat.Builder(Context context, String channelId)

fun pushNotification(message: String?, clickAtion: String?) {
        val ii = Intent(clickAtion)
        ii.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
        val pendingIntent = PendingIntent.getActivity(this, REQUEST_CODE, ii, PendingIntent.FLAG_ONE_SHOT)

        val soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION)

        val largIcon = BitmapFactory.decodeResource(applicationContext.resources,
                R.mipmap.ic_launcher)


        val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

        val channelId = "default_channel_id"
        val channelDescription = "Default Channel"
// Since android Oreo notification channel is needed.
//Check if notification channel exists and if not create one
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            var notificationChannel = notificationManager.getNotificationChannel(channelId)
            if (notificationChannel != null) {
                val importance = NotificationManager.IMPORTANCE_HIGH //Set the importance level
                notificationChannel = NotificationChannel(channelId, channelDescription, importance)
               // notificationChannel.lightColor = Color.GREEN //Set if it is necesssary
                notificationChannel.enableVibration(true) //Set if it is necesssary
                notificationManager.createNotificationChannel(notificationChannel)


                val noti_builder = NotificationCompat.Builder(this)
                        .setContentTitle("MMH")
                        .setContentText(message)
                        .setSmallIcon(R.drawable.ic_launcher_background)
                        .setChannelId(channelId)
                        .build()
                val random = Random()
                val id = random.nextInt()
                notificationManager.notify(id,noti_builder)

            }

        }
        else
        {
            val notificationBuilder = NotificationCompat.Builder(this)
                    .setSmallIcon(R.mipmap.ic_launcher).setColor(resources.getColor(R.color.colorPrimary))
                    .setVibrate(longArrayOf(200, 200, 0, 0, 0))
                    .setContentTitle(getString(R.string.app_name))

                    .setLargeIcon(largIcon)
                    .setContentText(message)
                    .setAutoCancel(true)
                    .setStyle(NotificationCompat.BigTextStyle().bigText(message))
                    .setSound(soundUri)
                    .setContentIntent(pendingIntent)


            val random = Random()
            val id = random.nextInt()
            notificationManager.notify(id, notificationBuilder.build())

        }



    }

Il pezzo di codice qui sotto funziona per me in Oreo, puoi provare questo. spero che funzionerà per te

private void sendNotification (contesto ctx, titolo stringa, int notificationNumber, messaggio stringa, sottotesto stringa, intento intento) {
try {

            PendingIntent pendingIntent = PendingIntent.getActivity(ctx, notificationNumber, intent,
                    PendingIntent.FLAG_UPDATE_CURRENT);
            Uri url = null;           
            NotificationCompat.Builder notificationBuilder = null;
            try {
                if (Build.VERSION.SDK_INT >= 26) {

                    try{
                        NotificationManager notificationManager = (NotificationManager)getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
                        notificationManager.deleteNotificationChannel(CHANNEL_ID_1);
                        notificationManager.deleteNotificationChannel(CHANNEL_ID_2);

                        if(!intent.getStringExtra("type").equalsIgnoreCase(""+TYPE_REQUEST)){
                            NotificationChannel breaking = new NotificationChannel(CHANNEL_ID_1, CHANNEL_ID_1_NAME, NotificationManager.IMPORTANCE_HIGH);
                            breaking.setShowBadge(false);
                            breaking.enableLights(true);
                            breaking.enableVibration(true);
                            breaking.setLightColor(Color.WHITE);
                            breaking.setVibrationPattern(new long[]{100, 200, 100, 200, 100, 200, 100});
                            breaking.setSound(url,new AudioAttributes.Builder().build());

                            notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID_1)
                                    .setSmallIcon(R.mipmap.ic_launcher);
                            notificationManager.createNotificationChannel(breaking);

                        }else{

                            NotificationChannel politics = new NotificationChannel(CHANNEL_ID_2,CHANNEL_ID_2_NAME, NotificationManager.IMPORTANCE_DEFAULT);
                            politics.setShowBadge(false);
                            politics.enableLights(true);
                            politics.enableVibration(true);
                            politics.setLightColor(Color.BLUE);
                            politics.setVibrationPattern(new long[]{100, 200, 100, 200, 100});
                            politics.setSound(url,new AudioAttributes.Builder().build());

                            notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID_2)
                                    .setSmallIcon(R.mipmap.ic_launcher);
                            notificationManager.createNotificationChannel(politics);
                        }
                    }catch (Exception e){
                        e.printStackTrace();
                    }

                } else {
                    notificationBuilder = new NotificationCompat.Builder(ctx)
                            .setSmallIcon(R.mipmap.ic_launcher);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }

            if (notificationBuilder == null) {
                notificationBuilder = new NotificationCompat.Builder(ctx)
                        .setSmallIcon(R.mipmap.ic_launcher);
            }


            notificationBuilder.setContentTitle(title);          
            notificationBuilder.setSubText(subtext);
            notificationBuilder.setAutoCancel(true);

            notificationBuilder.setContentIntent(pendingIntent);
            notificationBuilder.setNumber(notificationNumber);
            NotificationManager notificationManager =
                    (NotificationManager) ctx.getSystemService(Context.NOTIFICATION_SERVICE);

            notificationManager.notify(notificationNumber, notificationBuilder.build());

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

In Android Oreo, l'app di notifica viene eseguita utilizzando i canali e la classe NotificationHelper. Dovrebbe avere un ID canale e un nome canale.

Per prima cosa devi creare una classe NotificationHelper

public class NotificationHelper extends ContextWrapper {

private static final String EDMT_CHANNEL_ID="com.example.safna.notifier1.EDMTDEV";
private static final String EDMT_CHANNEL_NAME="EDMTDEV Channel";
private NotificationManager manager;

public  NotificationHelper(Context base)
{
    super(base);
    createChannels();
}
private void createChannels()
{
    NotificationChannel edmtChannel=new NotificationChannel(EDMT_CHANNEL_ID,EDMT_CHANNEL_NAME,NotificationManager.IMPORTANCE_DEFAULT);
    edmtChannel.enableLights(true);
    edmtChannel.enableVibration(true);
    edmtChannel.setLightColor(Color.GREEN);
    edmtChannel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);

    getManager().createNotificationChannel(edmtChannel);

}
public NotificationManager getManager()
{
   if (manager==null)
       manager=(NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
   return manager;

}
public NotificationCompat.Builder getEDMTChannelNotification(String title,String body)
{
    return new NotificationCompat.Builder(getApplicationContext(),EDMT_CHANNEL_ID)
            .setContentText(body)
            .setContentTitle(title)
            .setSmallIcon(R.mipmap.ic_launcher_round)
            .setAutoCancel(true);
    }
}

Crea un pulsante nel file xml di attività, quindi nell'attività principale

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    helper=new NotificationHelper(this);

    btnSend=(Button)findViewById(R.id.btnSend);

    btnSend.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String title="Title";
            String content="Content";
            Notification.Builder builder=helper.getEDMTChannelNotification(title,content);
            helper.getManager().notify(new Random().nextInt(),builder.build());
        }
    });

}

Quindi esegui il tuo progetto

È necessario creare un canale di notifica per livello API superiore a 26 (oreo).

`NotificationChannel channel = new NotificationChannel(STRING_ID,CHANNEL_NAME,NotificationManager.IMPORTANCE_HIGH);

STRING_ID = string string channelid è lo stesso di Notification.Builder come questo

`Notification notification = new Notification.Builder(this,STRING_ID)
            .setSmallIcon(android.R.drawable.ic_menu_help)
            .setContentTitle("Hello Notification")
            .setContentText("It is Working")
            .setContentIntent(pendingIntent)
            .build();`

L'ID canale nella notifica e nella notifica dovrebbe essere lo stesso. L'intero codice è come questo ... `

@RequiresApi(api = Build.VERSION_CODES.O)
  private void callNotification2() {

    Intent intent = new Intent(getApplicationContext(),MainActivity.class);
    PendingIntent pendingIntent = PendingIntent.getActivity(this,11, 
    intent,PendingIntent.FLAG_UPDATE_CURRENT);
    Notification notification = new Notification.Builder(this,"22")
            .setSmallIcon(android.R.drawable.ic_menu_help)
            .setContentTitle("Hello Notification")
            .setContentText("It is Working")
            .setContentIntent(pendingIntent)
            .build();
    NotificationChannel channel = new 
    NotificationChannel("22","newName",NotificationManager.IMPORTANCE_HIGH);
    NotificationManager manager = (NotificationManager) 
    getSystemService(NOTIFICATION_SERVICE);
    manager.createNotificationChannel(channel);
    manager.notify(11,notification);

    }'

Prima di tutto, se non lo sai, da Android Oreo, ovvero livello API 26, è obbligatorio che le notifiche vengano ridigitate con un canale.

In tal caso, molti tutorial potrebbero confonderti perché mostrano diversi esempi di notifica sopra oreo e sotto.

Quindi ecco un codice comune che funziona sia sopra che sotto oreo:

String CHANNEL_ID = "MESSAGE";
String CHANNEL_NAME = "MESSAGE";

NotificationManagerCompat manager = NotificationManagerCompat.from(MainActivity.this);

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    NotificationChannel channel = new NotificationChannel(CHANNEL_ID, CHANNEL_NAME,
    NotificationManager.IMPORTANCE_DEFAULT);
    manager.createNotificationChannel(channel);
}

Notification notification = new NotificationCompat.Builder(MainActivity.this,CHANNEL_ID)
        .setSmallIcon(R.drawable.ic_android_black_24dp)
        .setContentTitle(TitleTB.getText().toString())
        .setContentText(MessageTB.getText().toString())
        .build();
manager.notify(getRandomNumber(), notification); // In case you pass a number instead of getRandoNumber() then the new notification will override old one and you wont have more then one notification so to do so u need to pass unique number every time so here is how we can do it by "getRandoNumber()"

private static int getRandomNumber() {
    Date dd= new Date();
    SimpleDateFormat ft =new SimpleDateFormat ("mmssSS");
    String s=ft.format(dd);
    return Integer.parseInt(s);
}

Video Tutorial: VIDEO YOUTUBE

Se vuoi scaricare questa demo: GitHub Link

    NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, "CHANNEL_ID")
            ........

    NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        CharSequence name = "Hello";// The user-visible name of the channel.
        int importance = NotificationManager.IMPORTANCE_HIGH;
        NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);
        mNotificationManager.createNotificationChannel(mChannel);
    }
    mNotificationManager.notify(notificationId, notificationBuilder.build());