在 Flutter 中实现视频馈送的最佳方法是什么？

Question

I'm building an app in flutter that contains a Video Feed like the one found in TikTok. You can imagine a ListView where you can scroll through some videos (5-25seconds).

The videos are stored in Google Cloud Platform.

Currently, feed that contains more than 12 or even 9(on some devices with lower memories) is causing the app to crash, understandably.

Now, being an amateur myself, (barely connecting GCP to flutter and connecting it:p), I'm struggling to find a solution to be able to scroll through a feed of videos as smooth as possible. I was thinking something like a Carousel with a visibility detector, but I'm not sure how I can reload a video that has been disposed. My video player is "Video_player" package.

I'm open to anything, and appreciate the help!

Thanks, M

Answer 1

You can copy paste run full code below
You can use package https://pub.dev/packages/inview_notifier_list
Example code will auto play video when video is on screen within a provided area
code snippet

InViewNotifierList(
          scrollDirection: Axis.vertical,
          initialInViewIds: ['0'],
          isInViewPortCondition:
              (double deltaTop, double deltaBottom, double viewPortDimension) {
            return deltaTop < (0.5 * viewPortDimension) &&
                deltaBottom > (0.5 * viewPortDimension);
          },
          children: List.generate(
            30,
            (index) {
              return Container(
                width: double.infinity,
                height: 300.0,
                alignment: Alignment.center,
                margin: EdgeInsets.symmetric(vertical: 50.0),
                child: LayoutBuilder(
                  builder: (BuildContext context, BoxConstraints constraints) {
                    final InViewState inViewState =
                        InViewNotifierList.of(context);

                    inViewState.addContext(context: context, id: '$index');

                    return AnimatedBuilder(
                      animation: inViewState,
                      builder: (BuildContext context, Widget child) {
                        return VideoWidget(
                            play: inViewState.inView('$index'),
                            url:
                                'https://flutter.github.io/assets-for-api-docs/assets/videos/butterfly.mp4');
                      },

working demo

full code

import 'package:flutter/material.dart';
import 'package:inview_notifier_list/inview_notifier_list.dart';
import 'package:video_player/video_player.dart';

class VideoWidget extends StatefulWidget {
  final String url;
  final bool play;

  const VideoWidget({Key key, @required this.url, @required this.play})
      : super(key: key);
  @override
  _VideoWidgetState createState() => _VideoWidgetState();
}

class _VideoWidgetState extends State<VideoWidget> {
  VideoPlayerController _controller;
  Future<void> _initializeVideoPlayerFuture;

  @override
  void initState() {
    super.initState();
    _controller = VideoPlayerController.network(widget.url);
    _initializeVideoPlayerFuture = _controller.initialize().then((_) {
      // Ensure the first frame is shown after the video is initialized, even before the play button has been pressed.
      setState(() {});
    });

    if (widget.play) {
      _controller.play();
      _controller.setLooping(true);
    }
  }

  @override
  void didUpdateWidget(VideoWidget oldWidget) {
    if (oldWidget.play != widget.play) {
      if (widget.play) {
        _controller.play();
        _controller.setLooping(true);
      } else {
        _controller.pause();
      }
    }
    super.didUpdateWidget(oldWidget);
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _initializeVideoPlayerFuture,
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.done) {
          return VideoPlayer(_controller);
        } else {
          return Center(
            child: CircularProgressIndicator(),
          );
        }
      },
    );
  }
}

class VideoList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Stack(
      fit: StackFit.expand,
      children: <Widget>[
        InViewNotifierList(
          scrollDirection: Axis.vertical,
          initialInViewIds: ['0'],
          isInViewPortCondition:
              (double deltaTop, double deltaBottom, double viewPortDimension) {
            return deltaTop < (0.5 * viewPortDimension) &&
                deltaBottom > (0.5 * viewPortDimension);
          },
          children: List.generate(
            30,
            (index) {
              return Container(
                width: double.infinity,
                height: 300.0,
                alignment: Alignment.center,
                margin: EdgeInsets.symmetric(vertical: 50.0),
                child: LayoutBuilder(
                  builder: (BuildContext context, BoxConstraints constraints) {
                    final InViewState inViewState =
                        InViewNotifierList.of(context);

                    inViewState.addContext(context: context, id: '$index');

                    return AnimatedBuilder(
                      animation: inViewState,
                      builder: (BuildContext context, Widget child) {
                        return VideoWidget(
                            play: inViewState.inView('$index'),
                            url:
                                'https://flutter.github.io/assets-for-api-docs/assets/videos/butterfly.mp4');
                      },
                    );
                  },
                ),
              );
            },
          ),
        ),
        Align(
          alignment: Alignment.center,
          child: Container(
            height: 1.0,
            color: Colors.redAccent,
          ),
        )
      ],
    );
  }
}

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(child: VideoList()),
          ],
        ),
      ),
    );
  }
}