A ImageProvider from the photo's assetId of photo gallery

gistfile1.txt

import 'dart:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:photo_manager/photo_manager.dart';

import 'package:flutter/material.dart';

class PhotoAssetEntityImageProvider extends ImageProvider<String> {
  const PhotoAssetEntityImageProvider(this.photoId);

  final String photoId;

  @override
  Future<String> obtainKey(ImageConfiguration configuration) {
    return SynchronousFuture<String>(photoId);
  }


  @override
  ImageStreamCompleter loadImage(String key, ImageDecoderCallback decode) {
    return MultiFrameImageStreamCompleter(
      codec: _loadAsync(key),
      scale: 1.0,
      informationCollector: () sync* {
        yield DiagnosticsProperty<ImageProvider>('Image provider', this);
        yield DiagnosticsProperty<String>('Image key', key);
      },
    );
  }

  Future<ui.Codec> _loadAsync(String key) async {
    final AssetEntity? assetEntity = await AssetEntity.fromId(key);
    final Uint8List? data = await assetEntity?.originBytes;
    if (data != null) {
      ui.Codec codec = await ui.instantiateImageCodec(data);
      return codec;
    }
    throw StateError('Failed to load image data for $key');
  }

}