fix null-safety bugs

avdosev · avdosev · commit c36ae4d2590b · 2021-08-22T19:38:16.000+03:00
diff --git a/lib/habr/json_parsing.dart b/lib/habr/json_parsing.dart
@@ -70,11 +70,11 @@ PostPreviews parsePostPreviewsFromJson(Map<String, dynamic> data) {
           corporative: article['isCorporative'],
           title: _prepareHtmlString(article['titleHtml']),
           hubs: article['hubs']
-              .map<String>((flow) => flow['title'] as String?)
+              .map<String>((flow) => flow['title'] as String)
               .toList(),
           htmlPreview: "<div>${article['leadData']['textHtml']}</div>",
           flows: article['flows']
-              .map<String>((flow) => flow['title'] as String?)
+              .map<String>((flow) => flow['title'] as String)
               .toList(),
           publishDate: DateTime.parse(article['timePublished']),
           author: parseAuthorFromJson(article['author']),
diff --git a/lib/pages/filters.dart b/lib/pages/filters.dart
@@ -7,6 +7,7 @@ import 'package:habr_app/widgets/adaptive_ui.dart';
 import 'package:itertools/itertools.dart';
 import 'package:hive/hive.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+import 'package:tuple_dart/tuple.dart';
 
 class FiltersPage extends StatefulWidget {
   @override
@@ -28,38 +29,46 @@ class _FiltersPageState extends State<FiltersPage> {
     );
   }
 
+  List<Tuple2<int, ChildT>>
+      _filterChildType<ChildT extends Filter<PostPreview>>(
+          Iterable<Tuple2<int, Filter<PostPreview>>> filtersWithIndex) {
+    return filtersWithIndex
+        .where((e) => e.item2 is ChildT)
+        .map((e) => e.withItem2(e.item2 as ChildT))
+        .toList(growable: false);
+  }
+
   Widget _buildBody() {
+    final filtersStore = FiltersStorage();
+    final removeFilter = (int i) => () => filtersStore.removeFilterAt(i);
     return ValueListenableBuilder<Box<Filter<PostPreview>>>(
-      valueListenable: FiltersStorage().listenable(),
-      builder: (context, box, child) => ListView(
-        children: box.values
-            .mapIndexed<Widget>((i, filter) {
-              if (filter is NicknameAuthorFilter) {
-                return ListTile(
-                  leading: const Icon(Icons.person_outline),
-                  title: Text(filter.nickname!),
-                  trailing: IconButton(
-                    icon: const Icon(Icons.clear),
-                    onPressed: () => FiltersStorage().removeFilterAt(i),
-                  ),
-                );
-              } else if (filter is CompanyNameFilter) {
-                return ListTile(
-                  leading: const Icon(Icons.groups),
-                  title: Text(filter.companyName!),
-                  trailing: IconButton(
-                    icon: const Icon(Icons.clear),
-                    onPressed: () => FiltersStorage().removeFilterAt(i),
-                  ),
-                );
-              } else {
-                logInfo("filter not supported");
-              }
-              return null;
-            } as Widget Function(int, Filter<PostPreview>))
-            .map((e) => DefaultConstraints(child: e))
-            .toList(),
-      ),
+      valueListenable: filtersStore.listenable(),
+      builder: (context, box, child) {
+        final filtersWithIndex = box.values.enumerate().toList();
+        final filtersByAuthor =
+            _filterChildType<NicknameAuthorFilter>(filtersWithIndex);
+        final filtersByCompany =
+            _filterChildType<CompanyNameFilter>(filtersWithIndex);
+
+        return ListView(
+          children: [
+            if (filtersByAuthor.isNotEmpty)
+              FiltersGroup<NicknameAuthorFilter>(
+                filters: filtersByAuthor,
+                leading: const Icon(Icons.person_outline),
+                titleBuilder: (filter) => Text(filter.nickname),
+                onRemoveBuilder: removeFilter,
+              ),
+            if (filtersByCompany.isNotEmpty)
+              FiltersGroup<CompanyNameFilter>(
+                filters: filtersByCompany,
+                leading: const Icon(Icons.groups),
+                titleBuilder: (filter) => Text(filter.companyName),
+                onRemoveBuilder: removeFilter,
+              ),
+          ].map((e) => DefaultConstraints(child: e)).toList(growable: false),
+        );
+      },
     );
   }
 
@@ -117,6 +126,40 @@ class _FiltersPageState extends State<FiltersPage> {
   }
 }
 
+class FiltersGroup<FilterT extends Filter<PostPreview>>
+    extends StatelessWidget {
+  final Iterable<Tuple2<int, FilterT>> filters;
+  final Widget leading;
+  final Widget Function(FilterT) titleBuilder;
+  final void Function() Function(int) onRemoveBuilder;
+
+  FiltersGroup({
+    required this.filters,
+    required this.leading,
+    required this.titleBuilder,
+    required this.onRemoveBuilder,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Card(
+      child: Column(
+        children: filters.map((tuple) {
+          final index = tuple.item1;
+          final filter = tuple.item2;
+          return ListTile(
+              leading: leading,
+              title: titleBuilder(filter),
+              trailing: IconButton(
+                icon: const Icon(Icons.clear),
+                onPressed: onRemoveBuilder(index),
+              ));
+        }).toList(growable: false),
+      ),
+    );
+  }
+}
+
 enum _DialogType {
   AuthorNickname,
   CompanyName,
diff --git a/lib/utils/filters/article_preview_filters.dart b/lib/utils/filters/article_preview_filters.dart
@@ -4,7 +4,7 @@ import 'package:habr_app/models/post_preview.dart';
 export 'filter.dart';
 
 class NicknameAuthorFilter extends Filter<PostPreview> {
-  final String? nickname;
+  final String nickname;
 
   const NicknameAuthorFilter(this.nickname);
 
@@ -22,19 +22,19 @@ class ScoreArticleFilter extends Filter<PostPreview> {
 
   @override
   bool filter(PostPreview obj) {
-    return (min != null && obj.statistics.score< min!) ||
-        (max != null && obj.statistics.score> max!);
+    return (min != null && obj.statistics.score < min!) ||
+        (max != null && obj.statistics.score > max!);
   }
 }
 
 class CompanyNameFilter extends Filter<PostPreview> {
-  final String? companyName;
+  final String companyName;
 
   const CompanyNameFilter(this.companyName);
 
   @override
   bool filter(PostPreview postPreview) {
-    final l = companyName!.toLowerCase();
+    final l = companyName.toLowerCase();
     return postPreview.hubs
             ?.any((element) => element.toLowerCase().contains(l)) ??
         false;
diff --git a/lib/widgets/dividing_block.dart b/lib/widgets/dividing_block.dart
@@ -1,21 +1,22 @@
 import 'package:flutter/material.dart';
 
 class WrappedContainer extends StatelessWidget {
-  final List<Widget?>? children;
+  final List<Widget> children;
   final double distance;
 
-  WrappedContainer({this.children, this.distance = 20});
+  WrappedContainer({required this.children, this.distance = 20});
 
   @override
   Widget build(BuildContext context) {
-    final wrappedChildren = <Widget?>[];
-    for (int i = 0; i < children!.length; i++) {
-      wrappedChildren.add(children![i]);
-      if (i != children!.length - 1) wrappedChildren.add(SizedBox(height: distance));
+    final wrappedChildren = <Widget>[];
+    for (int i = 0; i < children.length; i++) {
+      wrappedChildren.add(children[i]);
+      if (i != children.length - 1)
+        wrappedChildren.add(SizedBox(height: distance));
     }
     return Column(
       crossAxisAlignment: CrossAxisAlignment.stretch,
-      children: wrappedChildren as List<Widget>,
+      children: wrappedChildren,
     );
   }
-}
+}
diff --git a/lib/widgets/html_elements/unordered_list.dart b/lib/widgets/html_elements/unordered_list.dart
@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 
 class UnorderedList extends StatelessWidget {
-  final List<Widget?> children;
+  final List<Widget> children;
   UnorderedList({required this.children});
 
   @override
@@ -18,15 +18,16 @@ class UnorderedList extends StatelessWidget {
 }
 
 class UnorderedItem extends StatelessWidget {
-  final Widget? child;
+  final Widget child;
 
   UnorderedItem({required this.child});
 
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context).textTheme.bodyText2!;
     final bulletSize = 5;
-    final centerBaseline = (theme.fontSize! * theme.height! - bulletSize / 2) / 2;
+    final centerBaseline =
+        (theme.fontSize! * theme.height! - bulletSize / 2) / 2;
     return Row(
       crossAxisAlignment: CrossAxisAlignment.start,
       mainAxisAlignment: MainAxisAlignment.start,
@@ -35,7 +36,7 @@ class UnorderedItem extends StatelessWidget {
           child: const Bullet(),
           padding: EdgeInsets.only(right: 10, top: centerBaseline),
         ),
-        Expanded(child: child!)
+        Expanded(child: child),
       ],
     );
   }
diff --git a/lib/widgets/html_view.dart b/lib/widgets/html_view.dart
@@ -2,6 +2,7 @@ import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:habr_app/stores/app_settings.dart';
 import 'package:provider/provider.dart';
+import 'package:itertools/itertools.dart';
 
 import 'html_elements/html_elements.dart';
 import 'dividing_block.dart';
@@ -64,8 +65,8 @@ Widget? buildTree(view.Node element, BuildContext context, BuildParams params) {
     widget = Text.rich(
       TextSpan(
           children: element.children
-              .map<InlineSpan?>((child) => buildInline(child, context, params))
-              .toList() as List<InlineSpan>?),
+              .map<InlineSpan>((child) => buildInline(child, context, params))
+              .toList()),
       textAlign: params.textAlign,
     );
   } else if (element is view.Scrollable) {
@@ -102,11 +103,15 @@ Widget? buildTree(view.Node element, BuildContext context, BuildParams params) {
   } else if (element is view.BlockList) {
     // TODO: ordered list
     widget = UnorderedList(
-        children: element.children.map<Widget?>((li) => buildTree(li, context, params))
+        children: element.children
+            .map<Widget?>((li) => buildTree(li, context, params))
+            .notNull
             .toList());
   } else if (element is view.BlockColumn) {
     widget = WrappedContainer(
-        children: element.children.map<Widget?>((child) => buildTree(child, context, params))
+        children: element.children
+            .map<Widget?>((child) => buildTree(child, context, params))
+            .notNull
             .toList());
   } else if (element is view.Details) {
     widget = Spoiler(
@@ -143,7 +148,7 @@ Widget? buildTree(view.Node element, BuildContext context, BuildParams params) {
   return widget;
 }
 
-InlineSpan? buildInline(
+InlineSpan buildInline(
     view.Span element, BuildContext context, BuildParams params) {
   late InlineSpan span;
   if (element is view.TextSpan) {
@@ -181,7 +186,7 @@ Iterable<Widget> inlineTree(
     }
   } else if (element is view.BlockList) {
     for (final item in element.children) {
-      yield UnorderedItem(child: buildTree(item, context, params));
+      yield UnorderedItem(child: buildTree(item, context, params)!);
     }
   } else {
     yield buildTree(element!, context, params)!;
diff --git a/lib/widgets/statistics_icons.dart b/lib/widgets/statistics_icons.dart
