Update for picked asset error.

example/lib/main.dart

 
     if (imgList == null || imgList.isEmpty) {
       showToast("No pick item.");
+      return;
     } else {
       List<String> r = [];
       for (var e in imgList) {

lib/src/ui/page/photo_main_page.dart

   void didChangeDependencies() {
     super.didChangeDependencies();
     if (!_isInit) {
-      addPickedAsset(PhotoPickerProvider.of(context).pickedAssetList.toList());
+      final pickedList = PhotoPickerProvider.of(context).pickedAssetList ?? [];
+      addPickedAsset(pickedList.toList());
       _refreshList();
     }
   }

pubspec.lock

     dependency: transitive
     description:
       name: archive
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.0.11"
   args:
     dependency: transitive
     description:
       name: args
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.5.2"
   async:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.4.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.0.5"
   charcode:
     dependency: transitive
     description:
       name: charcode
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.1.2"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.14.11"
   convert:
     dependency: transitive
     description:
       name: convert
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.1.1"
   crypto:
     dependency: transitive
     description:
       name: crypto
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.1.3"
   flutter:
     dependency: transitive
     description:
       name: image
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.1.4"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "0.12.6"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.1.8"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.6.4"
   pedantic:
     dependency: transitive
     description:
       name: pedantic
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.8.0+1"
   petitparser:
     dependency: transitive
     description:
       name: petitparser
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.4.0"
   photo_manager:
     dependency: "direct main"
     description:
       name: photo_manager
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.4.7"
+    version: "0.4.8"
   quiver:
     dependency: transitive
     description:
       name: quiver
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.0.5"
   sky_engine:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.5.5"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.9.3"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.0.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.0.5"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.1.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "0.2.11"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "1.1.6"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "2.0.8"
   xml:
     dependency: transitive
     description:
       name: xml
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
     version: "3.5.0"
 sdks: