1、增加加载网络图片utils，LoadNetImage

lib/utils/load_net_image.dart

+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:flutter/material.dart';
+import 'package:octo_image/octo_image.dart';
+
+class LoadNetImage {
+
+  static String domain = "";
+
+  static load(
+    String? url, {
+    String? domain,
+    ImageTransformerType type = ImageTransformerType.Rect,
+    double? width,
+    double? height,
+  }) {
+    var domainUrl = domain ?? LoadNetImage.domain;
+    if (url != null && !url.startsWith("http")) {
+      url = domainUrl + url;
+    }
+
+    return OctoImage(
+      image: CachedNetworkImageProvider(url ?? ""),
+      imageBuilder: type == ImageTransformerType.Rect
+          ? MyOctoImageTransformer.radiusAvatar()
+          : MyOctoImageTransformer.circleAvatar(),
+      errorBuilder: OctoError.icon(color: Colors.red),
+      fit: BoxFit.cover,
+      width: width,
+      height: height,
+    );
+  }
+}
+
+class MyOctoImageTransformer {
+  static OctoImageBuilder radiusAvatar() {
+    return (context, child) => Center(
+          child: AspectRatio(
+            aspectRatio: 1.0,
+            child: ClipRRect(
+              borderRadius: BorderRadius.circular(5.0),
+              child: child,
+            ),
+          ),
+        );
+  }
+
+  static OctoImageBuilder circleAvatar() {
+    return (context, child) => Center(
+          child: AspectRatio(
+            aspectRatio: 1.0,
+            child: ClipOval(
+              child: child,
+            ),
+          ),
+        );
+  }
+}
+
+enum ImageTransformerType {
+  Rect, // 矩形
+  circle, // 圆形
+}