PUSHNotificationWithScheduleActivity.java

package com.example.myapplication;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Build;
import android.os.Handler;
import android.support.v4.app.NotificationCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Timer;
import java.util.TimerTask;

//<uses-permission android:name="android.permission.POST_NOTIFICATIONS" />

public class PUSHNotificationWithScheduleActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_p_u_s_h_notification_with_schedule);
        startTimer();
    }

    //Code for PUSH notifications
    NotificationManager notificationManager = null;
    public void createNotification(String title, String body) {
        final int NOTIFY_ID = 1000;

        // There are hardcoding only for show it's just strings
        String name = "my_package_channel";
        String id = "my_package_channel_1"; // The user-visible name of the channel.
        String description = "my_package_first_channel"; // The user-visible description of the channel.

        Intent intent;
        PendingIntent pendingIntent;
        NotificationCompat.Builder builder;

        if (notificationManager == null) {
            notificationManager =
                    (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
        }

        //Code for current versions
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            int importance = NotificationManager.IMPORTANCE_HIGH;
            NotificationChannel mChannel = notificationManager.getNotificationChannel(id);
            if (mChannel == null) {
                mChannel = new NotificationChannel(id, name, importance);
                mChannel.setDescription(description);
                mChannel.enableVibration(true);
                mChannel.setLightColor(Color.GREEN);
                mChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
                notificationManager.createNotificationChannel(mChannel);
            }
            builder = new NotificationCompat.Builder(this, id);
            intent = new Intent(this, PUSHNotificationWithScheduleActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
            pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);

            builder.setContentTitle(title)  // required
                    .setSmallIcon(android.R.drawable.ic_popup_reminder) // required
                    .setContentText(body)  // required
                    .setDefaults(Notification.DEFAULT_ALL)
                    .setAutoCancel(true)
                    .setContentIntent(pendingIntent)
                    .setTicker(title)
                    .setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
        } else {
            //code for older versions
            builder = new NotificationCompat.Builder(this);
            intent = new Intent(this, MainActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
            pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
            builder.setContentTitle(title)                           // required
                    .setSmallIcon(android.R.drawable.ic_popup_reminder) // required
                    .setContentText(body)  // required
                    .setDefaults(Notification.DEFAULT_ALL)
                    .setAutoCancel(true)
                    .setContentIntent(pendingIntent)
                    .setTicker(title)
                    .setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400})
                    .setPriority(Notification.PRIORITY_HIGH);
        }

        Notification notification = builder.build();
        notificationManager.notify(NOTIFY_ID, notification);
    }

    //code for scheduling notifications
    Timer timer;
    TimerTask timerTask;
    final Handler handler = new Handler();

    public void startTimer() {
        timer = new Timer();
        initializeTimerTask();
        timer.schedule(timerTask, 5000, 10000); //
    }

    public void initializeTimerTask() {
        timerTask = new TimerTask() {
            public void run() {
                handler.post(new Runnable() {
                    public void run() {
                        double random = Math.random();
                        final String  body = "There is a important value selected.";
                        if(random > 0.5) { //Here comes your custom logic
                            createNotification("PUSH Notification", body);
                            TextView tv = findViewById(R.id.textViewRandomValue);
                            tv.setText(String.valueOf(random));
                        }
                    }
                });
            }
        };
    }
}