TV: improved support for Licenses

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 
 ## <a id="unreleased"></a>[Unreleased]
 
+### Added
+
+- TV: improved support for Licenses
+
 ### Fixed
 
 - Viewer: playing video from app content provider

lib/widgets/about/licenses.dart

@@ -4,6 +4,7 @@ import 'package:aves/ref/brand_colors.dart';
 import 'package:aves/theme/colors.dart';
 import 'package:aves/utils/dependencies.dart';
 import 'package:aves/widgets/about/title.dart';
+import 'package:aves/widgets/about/tv_license_page.dart';
 import 'package:aves/widgets/common/basic/link_chip.dart';
 import 'package:aves/widgets/common/extensions/build_context.dart';
 import 'package:aves/widgets/common/identity/aves_expansion_tile.dart';
@@ -87,7 +88,7 @@ class _LicensesState extends State<Licenses> {
                         // as of Flutter v1.22.4, `cardColor` is used as a background color by `LicensePage`
                         cardColor: Theme.of(context).scaffoldBackgroundColor,
                       ),
-                      child: const LicensePage(),
+                      child: settings.useTvLayout ? const TvLicensePage() : const LicensePage(),
                     ),
                   ),
                 ),

lib/widgets/about/tv_license_page.dart

@@ -0,0 +1,357 @@
+import 'package:aves/widgets/common/basic/scaffold.dart';
+import 'package:aves/widgets/common/behaviour/intents.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/scheduler.dart';
+import 'package:flutter/services.dart';
+
+// as of Flutter v3.7.7, `LicensePage` is not designed for Android TV
+// and gets rejected from Google Play review:
+// ```
+// Your app’s text is cut off at the edge of the screen.
+// Apps should not display any text or functionality that is partially cut off by the edges of the screen.
+// For example, your app (version code 94) in the "Show All Licenses" section text is cut off from the bottom of the screen.
+// ```
+class TvLicensePage extends StatefulWidget {
+  const TvLicensePage({super.key});
+
+  @override
+  State<TvLicensePage> createState() => _TvLicensePageState();
+}
+
+class _TvLicensePageState extends State<TvLicensePage> {
+  final FocusNode _railFocusNode = FocusNode();
+  final ScrollController _detailsScrollController = ScrollController();
+  final ValueNotifier<int> _railIndexNotifier = ValueNotifier(0);
+
+  final Future<_LicenseData> licenses = LicenseRegistry.licenses
+      .fold<_LicenseData>(
+        _LicenseData(),
+        (prev, license) => prev..addLicense(license),
+      )
+      .then((licenseData) => licenseData..sortPackages());
+
+  @override
+  void dispose() {
+    _railIndexNotifier.dispose();
+    _railFocusNode.dispose();
+    _detailsScrollController.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AvesScaffold(
+      appBar: AppBar(
+        automaticallyImplyLeading: false,
+        title: Text(MaterialLocalizations.of(context).licensesPageTitle),
+      ),
+      body: ValueListenableBuilder<int>(
+        valueListenable: _railIndexNotifier,
+        builder: (context, selectedIndex, child) {
+          return FutureBuilder<_LicenseData>(
+            future: licenses,
+            builder: (context, snapshot) {
+              final data = snapshot.data;
+              if (data == null) {
+                return const Center(
+                  child: CircularProgressIndicator(),
+                );
+              }
+
+              final packages = data.packages;
+              final rail = Focus(
+                focusNode: _railFocusNode,
+                skipTraversal: true,
+                canRequestFocus: false,
+                child: ConstrainedBox(
+                  constraints: BoxConstraints.loose(const Size.fromWidth(300)),
+                  child: ListView.builder(
+                    itemBuilder: (context, index) {
+                      final packageName = packages[index];
+                      final bindings = data.packageLicenseBindings[packageName]!;
+                      final isSelected = index == selectedIndex;
+                      return Ink(
+                        color: isSelected ? Theme.of(context).highlightColor : Theme.of(context).cardColor,
+                        child: ListTile(
+                          title: Text(packageName),
+                          subtitle: Text(MaterialLocalizations.of(context).licensesPackageDetailText(bindings.length)),
+                          selected: isSelected,
+                          onTap: () => _railIndexNotifier.value = index,
+                        ),
+                      );
+                    },
+                    itemCount: packages.length,
+                  ),
+                ),
+              );
+
+              final packageName = packages[selectedIndex];
+              final bindings = data.packageLicenseBindings[packageName]!;
+
+              return SafeArea(
+                child: Row(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    const SizedBox(width: 16),
+                    rail,
+                    Expanded(
+                      child: FocusableActionDetector(
+                        shortcuts: const {
+                          SingleActivator(LogicalKeyboardKey.arrowUp): ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page),
+                          SingleActivator(LogicalKeyboardKey.arrowDown): ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page),
+                        },
+                        actions: {
+                          ScrollIntent: ScrollControllerAction(scrollController: _detailsScrollController),
+                        },
+                        child: KeyedSubtree(
+                          key: Key(packageName),
+                          child: _PackageLicensePage(
+                            packageName: packageName,
+                            licenseEntries: bindings.map((i) => data.licenses[i]).toList(growable: false),
+                            scrollController: _detailsScrollController,
+                          ),
+                        ),
+                      ),
+                    ),
+                  ],
+                ),
+              );
+            },
+          );
+        },
+      ),
+    );
+  }
+}
+
+// adapted from Flutter `_LicenseData` in `/material/about.dart`
+class _LicenseData {
+  final List<LicenseEntry> licenses = <LicenseEntry>[];
+  final Map<String, List<int>> packageLicenseBindings = <String, List<int>>{};
+  final List<String> packages = <String>[];
+
+  // Special treatment for the first package since it should be the package
+  // for delivered application.
+  String? firstPackage;
+
+  void addLicense(LicenseEntry entry) {
+    // Before the license can be added, we must first record the packages to
+    // which it belongs.
+    for (final String package in entry.packages) {
+      _addPackage(package);
+      // Bind this license to the package using the next index value. This
+      // creates a contract that this license must be inserted at this same
+      // index value.
+      packageLicenseBindings[package]!.add(licenses.length);
+    }
+    licenses.add(entry); // Completion of the contract above.
+  }
+
+  /// Add a package and initialize package license binding. This is a no-op if
+  /// the package has been seen before.
+  void _addPackage(String package) {
+    if (!packageLicenseBindings.containsKey(package)) {
+      packageLicenseBindings[package] = <int>[];
+      firstPackage ??= package;
+      packages.add(package);
+    }
+  }
+
+  /// Sort the packages using some comparison method, or by the default manner,
+  /// which is to put the application package first, followed by every other
+  /// package in case-insensitive alphabetical order.
+  void sortPackages([int Function(String a, String b)? compare]) {
+    packages.sort(compare ??
+        (a, b) {
+          // Based on how LicenseRegistry currently behaves, the first package
+          // returned is the end user application license. This should be
+          // presented first in the list. So here we make sure that first package
+          // remains at the front regardless of alphabetical sorting.
+          if (a == firstPackage) {
+            return -1;
+          }
+          if (b == firstPackage) {
+            return 1;
+          }
+          return a.toLowerCase().compareTo(b.toLowerCase());
+        });
+  }
+}
+
+// adapted from Flutter `_PackageLicensePage` in `/material/about.dart`
+class _PackageLicensePage extends StatefulWidget {
+  const _PackageLicensePage({
+    required this.packageName,
+    required this.licenseEntries,
+    required this.scrollController,
+  });
+
+  final String packageName;
+  final List<LicenseEntry> licenseEntries;
+  final ScrollController? scrollController;
+
+  @override
+  _PackageLicensePageState createState() => _PackageLicensePageState();
+}
+
+class _PackageLicensePageState extends State<_PackageLicensePage> {
+  @override
+  void initState() {
+    super.initState();
+    _initLicenses();
+  }
+
+  final List<Widget> _licenses = <Widget>[];
+  bool _loaded = false;
+
+  Future<void> _initLicenses() async {
+    for (final LicenseEntry license in widget.licenseEntries) {
+      if (!mounted) {
+        return;
+      }
+      final List<LicenseParagraph> paragraphs = await SchedulerBinding.instance.scheduleTask<List<LicenseParagraph>>(
+        license.paragraphs.toList,
+        Priority.animation,
+        debugLabel: 'License',
+      );
+      if (!mounted) {
+        return;
+      }
+      setState(() {
+        _licenses.add(const Padding(
+          padding: EdgeInsets.all(18.0),
+          child: Divider(),
+        ));
+        for (final LicenseParagraph paragraph in paragraphs) {
+          if (paragraph.indent == LicenseParagraph.centeredIndent) {
+            _licenses.add(Padding(
+              padding: const EdgeInsets.only(top: 16.0),
+              child: Text(
+                paragraph.text,
+                style: const TextStyle(fontWeight: FontWeight.bold),
+                textAlign: TextAlign.center,
+              ),
+            ));
+          } else {
+            _licenses.add(Padding(
+              padding: EdgeInsetsDirectional.only(top: 8.0, start: 16.0 * paragraph.indent),
+              child: Text(paragraph.text),
+            ));
+          }
+        }
+      });
+    }
+    setState(() {
+      _loaded = true;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final MaterialLocalizations localizations = MaterialLocalizations.of(context);
+    final ThemeData theme = Theme.of(context);
+    final String title = widget.packageName;
+    final String subtitle = localizations.licensesPackageDetailText(widget.licenseEntries.length);
+    const double pad = 24;
+    const EdgeInsets padding = EdgeInsets.only(left: pad, right: pad, bottom: pad);
+    final List<Widget> listWidgets = <Widget>[
+      ..._licenses,
+      if (!_loaded)
+        const Padding(
+          padding: EdgeInsets.symmetric(vertical: 24.0),
+          child: Center(
+            child: CircularProgressIndicator(),
+          ),
+        ),
+    ];
+
+    final Widget page;
+    if (widget.scrollController == null) {
+      page = Scaffold(
+        appBar: AppBar(
+          title: _PackageLicensePageTitle(
+            title,
+            subtitle,
+            theme.primaryTextTheme,
+          ),
+        ),
+        body: Center(
+          child: Material(
+            color: theme.cardColor,
+            elevation: 4.0,
+            child: Container(
+              constraints: BoxConstraints.loose(const Size.fromWidth(600.0)),
+              child: Localizations.override(
+                locale: const Locale('en', 'US'),
+                context: context,
+                child: ScrollConfiguration(
+                  // A Scrollbar is built-in below.
+                  behavior: ScrollConfiguration.of(context).copyWith(scrollbars: false),
+                  child: Scrollbar(
+                    child: ListView(padding: padding, children: listWidgets),
+                  ),
+                ),
+              ),
+            ),
+          ),
+        ),
+      );
+    } else {
+      page = CustomScrollView(
+        controller: widget.scrollController,
+        slivers: <Widget>[
+          SliverAppBar(
+            automaticallyImplyLeading: false,
+            pinned: true,
+            backgroundColor: theme.cardColor,
+            title: _PackageLicensePageTitle(title, subtitle, theme.textTheme),
+          ),
+          SliverPadding(
+            padding: padding,
+            sliver: SliverList(
+              delegate: SliverChildBuilderDelegate(
+                (context, index) => Localizations.override(
+                  locale: const Locale('en', 'US'),
+                  context: context,
+                  child: listWidgets[index],
+                ),
+                childCount: listWidgets.length,
+              ),
+            ),
+          ),
+        ],
+      );
+    }
+    return DefaultTextStyle(
+      style: theme.textTheme.bodySmall!,
+      child: page,
+    );
+  }
+}
+
+class _PackageLicensePageTitle extends StatelessWidget {
+  const _PackageLicensePageTitle(
+    this.title,
+    this.subtitle,
+    this.theme,
+  );
+
+  final String title;
+  final String subtitle;
+  final TextTheme theme;
+
+  @override
+  Widget build(BuildContext context) {
+    final Color? color = Theme.of(context).appBarTheme.foregroundColor;
+
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: <Widget>[
+        Text(title, style: theme.titleLarge?.copyWith(color: color)),
+        Text(subtitle, style: theme.titleSmall?.copyWith(color: color)),
+      ],
+    );
+  }
+}

lib/widgets/settings/settings_page.dart

@@ -97,8 +97,15 @@ class _SettingsPageState extends State<SettingsPage> with FeedbackMixin {
                         primary: false,
                       ),
                     ),
-                    const Expanded(
+                    Expanded(
-                      child: _TvRail(),
+                      child: MediaQuery.removePadding(
+                        context: context,
+                        removeLeft: true,
+                        removeTop: true,
+                        removeRight: true,
+                        removeBottom: true,
+                        child: const _TvRail(),
+                      ),
                     ),
                   ],
                 ),

pubspec.yaml

@@ -163,6 +163,10 @@ flutter:
 #  `OutputBuffer` in `/services/common/output_buffer.dart`
 #  adapts from Flutter v3.3.3 `_OutputBuffer` in `/foundation/consolidate_response.dart`
 #
+#  `TvLicensePage` in `/widgets/about/tv_license_page.dart`
+#  adapts from Flutter v3.7.7 `_LicenseData` in `/material/about.dart`
+#  and `_PackageLicensePage` in `/material/about.dart`
+#
 #  `OverlaySnackBar` in `/widgets/common/action_mixins/overlay_snack_bar.dart`
 #  adapts from Flutter v3.3.3 `SnackBar` in `/material/snack_bar.dart`
 #