How to show a Notification on Oreo?

Question

Notification doesn\'t shown on above V26 API.Notification cshown on v25 but when i checked it on v27 than the notification doesn\'t appear. My code to StartService and create n

Answer 1

Create a new class and name it NotificationUtils, extending ContextWrapper.

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.content.ContextWrapper;
import android.graphics.Color;

public class NotificationUtils extends ContextWrapper {

    private NotificationManager mManager;
    public static final String ANDROID_CHANNEL_ID = "com.testandroid.pushnotifications.ANDROID";

    public static final String ANDROID_CHANNEL_NAME = "ANDROID CHANNEL";

    public NotificationUtils(Context base) {
        super(base);
        createChannels();
    }

    public void createChannels() {

        // create android channel
        NotificationChannel androidChannel = new NotificationChannel(ANDROID_CHANNEL_ID,
                ANDROID_CHANNEL_NAME, NotificationManager.IMPORTANCE_DEFAULT);
        // Sets whether notifications posted to this channel should display notification lights
        androidChannel.enableLights(true);
        // Sets whether notification posted to this channel should vibrate.
        androidChannel.enableVibration(true);
        // Sets the notification light color for notifications posted to this channel
        androidChannel.setLightColor(Color.GREEN);
        // Sets whether notifications posted to this channel appear on the lockscreen or not
        androidChannel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);

        getManager().createNotificationChannel(androidChannel);



    private NotificationManager getManager() {
        if (mManager == null) {
            mManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        }
        return mManager;
    }
}

We specify which notification should be sent to a channel in the Notification.Builder (Android API 25) constructor, where we pass it the channel id as the second argument.

public Notification.Builder getAndroidChannelNotification(String title, String body) {
    return new Notification.Builder(getApplicationContext(), ANDROID_CHANNEL_ID)
            .setContentTitle(title)
            .setContentText(body)
            .setSmallIcon(android.R.drawable.stat_notify_more)
            .setAutoCancel(true);
}

Let's create push notification from any of the activity to test,

Put in global scope:

private NotificationUtils mNotificationUtils;

Initialize in onCreate

mNotificationUtils = new NotificationUtils(this);

Generate notification on button click to test:

buttonSend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String title = "Test Notification";
                String text= "Oreo Device Push Notification is here";

                if(!TextUtils.isEmpty(title) && !TextUtils.isEmpty(text)) {
                    Notification.Builder nb = mNotificationUtils.
                            getAndroidChannelNotification(title, text);

                    mNotificationUtils.getManager().notify(101, nb.build());
                }
            }
        });