lunasea/lib/core/ui/network_image.dart

import 'package:flutter/material.dart';
import 'package:lunasea/core.dart';

class LunaNetworkImage extends ClipRRect {
  LunaNetworkImage({
    double height,
    double width,
    String url,
    @required String placeholderAsset,
    Map headers,
    bool roundCorners = true,
  }) : super(
          child: Container(
            child: Stack(
              fit: StackFit.expand,
              children: [
                Image.asset(
                  placeholderAsset,
                  height: height,
                  width: width,
                ),
                if (url != null && url.isNotEmpty)
                  FadeInImage(
                    height: height,
                    width: width,
                    fadeInDuration: Duration(
                        milliseconds: LunaUI.ANIMATION_IMAGE_FADE_IN_SPEED),
                    fadeOutDuration: Duration(milliseconds: 1),
                    placeholder: AssetImage(placeholderAsset),
                    fit: BoxFit.cover,
                    image: NetworkImage(url,
                        headers: headers?.cast<String, String>()),
                    imageErrorBuilder: (context, error, stack) => Container(
                      height: height,
                      width: width,
                    ),
                  ),
              ],
            ),
            height: height,
            width: width,
          ),
          borderRadius:
              roundCorners ? BorderRadius.circular(LunaUI.BORDER_RADIUS) : null,
        ) {
    // assert(height != null);
    // assert(width != null);
    assert(placeholderAsset != null);
  }
}