import 'package:flutter_youtube/flutter_youtube.dart';

var youtube = new FlutterYoutube();

youtube.playYoutubeVideoByUrl(
  apiKey: "<API_KEY>",
  videoUrl: "<Youtube Video URL>",
  autoPlay: true, //default falase
  fullScreen: true //default false
);

youtube.onVideoEnded.listen((onData) {
  //perform your action when video playing is done
});