stream-chat-flutter/packages/stream_chat_flutter/lib/src/video_thumbnail_image.dart

import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:shimmer/shimmer.dart';
import 'package:stream_chat_flutter/stream_chat_flutter.dart';
import 'package:video_thumbnail/video_thumbnail.dart';

import 'stream_svg_icon.dart';
import 'video_service.dart';

class VideoThumbnailImage extends StatefulWidget {
  final String video;
  final double width;
  final double height;
  final BoxFit fit;
  final ImageFormat format;
  final Widget Function(BuildContext, Object) errorBuilder;
  final WidgetBuilder placeholderBuilder;

  const VideoThumbnailImage({
    Key key,
    @required this.video,
    this.width,
    this.height,
    this.fit,
    this.format = ImageFormat.PNG,
    this.errorBuilder,
    this.placeholderBuilder,
  }) : super(key: key);

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

class _VideoThumbnailImageState extends State<VideoThumbnailImage> {
  Future<Uint8List> thumbnailFuture;

  @override
  void initState() {
    thumbnailFuture = VideoService.generateVideoThumbnail(
      video: widget.video,
      imageFormat: widget.format,
    );
    super.initState();
  }

  @override
  void didUpdateWidget(covariant VideoThumbnailImage oldWidget) {
    if (oldWidget.video != widget.video || oldWidget.format != widget.format) {
      thumbnailFuture = VideoService.generateVideoThumbnail(
        video: widget.video,
        imageFormat: widget.format,
      );
    }
    super.didUpdateWidget(oldWidget);
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<Uint8List>(
      future: thumbnailFuture,
      builder: (context, snapshot) {
        return AnimatedSwitcher(
          duration: const Duration(milliseconds: 350),
          child: Builder(
            key: ValueKey<AsyncSnapshot<Uint8List>>(snapshot),
            builder: (_) {
              if (snapshot.hasError) {
                return widget.errorBuilder?.call(context, snapshot.error) ??
                    Center(
                      child: StreamSvgIcon.error(),
                    );
              }
              if (!snapshot.hasData) {
                return Container(
                  constraints: BoxConstraints.expand(),
                  child: widget.placeholderBuilder?.call(context) ??
                      Shimmer.fromColors(
                        baseColor: StreamChatTheme.of(context)
                            .colorTheme
                            .greyGainsboro,
                        highlightColor:
                            StreamChatTheme.of(context).colorTheme.whiteSmoke,
                        child: Image.asset(
                          'images/placeholder.png',
                          fit: BoxFit.cover,
                          package: 'stream_chat_flutter',
                        ),
                      ),
                );
              }
              return Image.memory(
                snapshot.data,
                fit: widget.fit,
                height: widget.height,
                width: widget.width,
              );
            },
          ),
        );
      },
    );
  }
}