Create NotificationChannel object per Channel, with the desired options

NotificationUtils.java

public class NotificationUtils extends ContextWrapper {
  public static final String ANDROID_CHANNEL_ID = "com.androidstuff.tutsplustalerts.ANDROID";
  public static final String IOS_CHANNEL_ID = "com.androidstuff.tutsplustalerts.IOS";
  public static final String ANDROID_CHANNEL_NAME = "ANDROID CHANNEL";
  public static final String IOS_CHANNEL_NAME = "IOS CHANNEL";
  private NotificationManager notificationManager;
  
  //..
  
  public NotificationUtils(Context base) {
    super(base);
    createChannels();
  }
  

    private void createChannels() {
        getNotificationManager().createNotificationChannel(channelA());
        getNotificationManager().createNotificationChannel(channelB());
        //Alternatively, we can create multiple notification channels all at once, like below:
        //getNotificationManager().createNotificationChannels(channelListContainingAandBInstances);
    }

    private NotificationChannel channelB() {
        // create ios channel
        NotificationChannel iosChannel =
                new NotificationChannel(IOS_CHANNEL_ID,
                        IOS_CHANNEL_NAME,
                        NotificationManager.IMPORTANCE_HIGH);
        iosChannel.enableLights(true);
        iosChannel.enableVibration(true);
        iosChannel.setLightColor(Color.GRAY);
        iosChannel.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
        return iosChannel;
    }

    private NotificationChannel channelA() {
        // 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_PUBLIC);

        return androidChannel;
    }
  
  //..
}