Notifications don't appear

问题

I'm trying to develop an app that shows notifications when a new item is added.The user can select if he wants the notifications and the notification sound to show using two switch buttons. The app compiled without an error, there wasn't even an error on the stack trace but when I run the app on my phone and turn on the switches, the notification doesn't appear. What is wrong?

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
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.Bundle;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.NotificationManagerCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.CompoundButton;
import android.widget.Switch;

import java.util.Set;

import androidx.annotation.RequiresApi;

import static android.app.PendingIntent.getActivity;
import static android.content.Context.NOTIFICATION_SERVICE;
import static com.example.myevents.R.drawable.notification;


public class Settings extends AppCompatActivity {
    Switch simpleswitch1;
    Switch simpleswitch2;
    private Notification notification;
    NotificationManager manager;
    Notification myNotication;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_settings);


        simpleswitch1 = (Switch) findViewById(R.id.simpleswitch1);
        simpleswitch2 = (Switch) findViewById(R.id.simpleswitch2);
        simpleswitch1.setChecked(false);
        simpleswitch2.setChecked(false);
        simpleswitch1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @TargetApi(Build.VERSION_CODES.O)
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked){{
                    int notifyID = 1;
                    String CHANNEL_ID = "my_channel_01";// The id of the channel.
                    CharSequence name = "channel 1";// The user-visible name of the channel.
                    int importance = NotificationManager.IMPORTANCE_HIGH;
                    NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);

                    Intent intent = new Intent(Settings.this, Visitor.class);
                    intent.putExtra("yourpackage.notifyId", notifyID);
                    PendingIntent pIntent = PendingIntent.getActivity(Settings.this, 0, intent,
                            PendingIntent.FLAG_UPDATE_CURRENT);


// Create a notification and set the notification channel.
                    Notification notification =
                            new NotificationCompat.Builder(Settings.this)
                                    .setSmallIcon(R.drawable.notification)
                                    .setContentTitle("My Events")
                                    .setContentText("Νέα εκδήλωση κοντά σας!")
                                    .setChannelId(CHANNEL_ID).build();



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

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



                }