initialize Flutter video_player from API call?

I need to initialize the video player but the url is coming from an API call.

What i tried so far:

  late VideoPlayerController _controller;

  Future<Tweet> postsFuture = getPosts();

  static Future<Tweet> getPosts() async {
    ...
    return tweet;
  }

@override
  void initState() {
    super.initState();
    //_initializeVideoController();
  }

void _initializeVideoController(String videoUrl) {
    _controller = VideoPlayerController.networkUrl(Uri.parse(videoUrl))
      ..initialize().then((_) {
        setState(() {});
      });
  }

My Widget build is like this:

return Scaffold(
      body: Center(
        child: FutureBuilder<Tweet>(
          future: postsFuture,
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              final posts = snapshot.data!; 
              String? videoUrl = posts.video;

              if (videoUrl != null) {
                _initializeVideoController(videoUrl);

                return Center(
                  child: _controller.value.isInitialized
                      ? AspectRatio(
                          aspectRatio: _controller.value.aspectRatio,
                          child: VideoPlayer(_controller),
                        )
                      : Container(),
                );
              } ...
          },
        ),
      ),

but when i run this, i have this Exception:

LateError (LateInitializationError: Field '_controller@28272344' has not been initialized.)

What am I doing wrong?