Task reminder app for android. The app should allow users to schedule tasks and receive reminders when the task’s deadline approaches. But Android Push Notification not triggering. Basically createNotificationChannel is not getting triggered.

Below is the complete code:

    import android.app.NotificationChannel
    import android.app.NotificationManager
    import android.content.Context
    import android.os.Build
    import android.os.Bundle
    import android.widget.Toast
    import androidx.appcompat.app.AppCompatActivity
    import androidx.core.app.NotificationCompat
    import androidx.core.app.NotificationManagerCompat
    import kotlinx.android.synthetic.main.activity_main.*
    import java.text.SimpleDateFormat
    import java.util.*

    class MainActivity : AppCompatActivity() {

        private val tasks = mutableListOf<Task>()

        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)

            // Button click listener to add a new task
            addTaskButton.setOnClickListener {
                addTask()
            }

            // Simulate some tasks for demonstration
            tasks.add(Task("Task 1", "Description 1", getDate(1)))
            tasks.add(Task("Task 2", "Description 2", getDate(2)))
            tasks.add(Task("Task 3", "Description 3", getDate(3)))

            // Show tasks in the list view
            showTasks()
        }

        private fun addTask() {
            val title = taskTitleEditText.text.toString()
            val description = taskDescriptionEditText.text.toString()
            val deadline = taskDeadlineEditText.text.toString()

            if (title.isNotEmpty() && deadline.isNotEmpty()) {
                val task = Task(title, description, deadline)
                tasks.add(task)
                showTasks()

                // Schedule a reminder for the task deadline
                scheduleReminder(task)

                // Clear input fields
                taskTitleEditText.text.clear()
                taskDescriptionEditText.text.clear()
                taskDeadlineEditText.text.clear()
            } else {
                Toast.makeText(this, "Please enter title and deadline for the task", Toast.LENGTH_SHORT).show()
            }
        }

        private fun showTasks() {
            val adapter = TaskAdapter(this, tasks)
            taskListView.adapter = adapter
        }

        private fun scheduleReminder(task: Task) {
        val calendar = Calendar.getInstance()
        val sdf = SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.getDefault())
        calendar.time = sdf.parse(task.deadline)!!

        // Check if the deadline is in the past (bug introduced here)
        if (calendar.timeInMillis < System.currentTimeMillis()) {
            val notificationId = tasks.indexOf(task)
            val builder = NotificationCompat.Builder(this, "task_reminder")
                .setSmallIcon(R.drawable.ic_notification)
                .setContentTitle("Task Reminder")
                .setContentText("Don't forget to complete ${task.title}")
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)

            createNotificationChannel()

            with(NotificationManagerCompat.from(this)) {
                notify(notificationId, builder.build())
            }
            }
        }

        private fun createNotificationChannel() {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                val name = "Task Reminder"
                val descriptionText = "Reminder for pending tasks"
                val importance = NotificationManager.IMPORTANCE_DEFAULT
                val channel = NotificationChannel("task_reminder", name, importance).apply {
                    description = descriptionText
                }
                val notificationManager: NotificationManager =
                    getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
                notificationManager.createNotificationChannel(channel)
            }
        }

        private fun getDate(daysToAdd: Int): String {
            val calendar = Calendar.getInstance()
            calendar.add(Calendar.DAY_OF_YEAR, daysToAdd)
            val sdf = SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.getDefault())
            return sdf.format(calendar.time)
        }
    }

data class Task(val title: String, val description: String, val deadline: String)

createNotificationChannel is not getting triggered