[video_player] Migrate video player to null safety (#3165)

* Migrate video player to null safety

* Fixes

* Double quotes -> single quotes

* Format and lint

* feedback

* Test example app

* Fix analyzer

Author: Emmanuel Garcia

packages/video_player/video_player/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.12.0
+
+* Migration to null safety.
+
 ## 0.11.1+2
 
 * Update android compileSdkVersion to 29.

packages/video_player/video_player/analysis_options.yaml

@@ -0,0 +1,4 @@
+include: ../../../analysis_options.yaml
+analyzer:
+  enable-experiment:
+    - non-nullable

packages/video_player/video_player/example/integration_test/video_player_test.dart

@@ -11,7 +11,7 @@ const Duration _playDuration = Duration(seconds: 1);
 
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
-  VideoPlayerController _controller;
+  late VideoPlayerController _controller;
   tearDown(() async => _controller.dispose());
 
   group('asset videos', () {
@@ -22,7 +22,7 @@ void main() {
     testWidgets('can be initialized', (WidgetTester tester) async {
       await _controller.initialize();
 
-      expect(_controller.value.initialized, true);
+      expect(_controller.value.isInitialized, true);
       expect(_controller.value.position, const Duration(seconds: 0));
       expect(_controller.value.isPlaying, false);
       expect(_controller.value.duration,

packages/video_player/video_player/example/lib/main.dart

@@ -108,7 +108,7 @@ class _ButterFlyAssetVideoInList extends StatelessWidget {
 
 /// A filler card to show the video in a list of scrolling contents.
 class _ExampleCard extends StatelessWidget {
-  const _ExampleCard({Key key, this.title}) : super(key: key);
+  const _ExampleCard({Key? key, required this.title}) : super(key: key);
 
   final String title;
 
@@ -150,7 +150,7 @@ class _ButterFlyAssetVideo extends StatefulWidget {
 }
 
 class _ButterFlyAssetVideoState extends State<_ButterFlyAssetVideo> {
-  VideoPlayerController _controller;
+  late VideoPlayerController _controller;
 
   @override
   void initState() {
@@ -206,7 +206,7 @@ class _BumbleBeeRemoteVideo extends StatefulWidget {
 }
 
 class _BumbleBeeRemoteVideoState extends State<_BumbleBeeRemoteVideo> {
-  VideoPlayerController _controller;
+  late VideoPlayerController _controller;
 
   Future<ClosedCaptionFile> _loadCaptions() async {
     final String fileContents = await DefaultAssetBundle.of(context)
@@ -265,7 +265,8 @@ class _BumbleBeeRemoteVideoState extends State<_BumbleBeeRemoteVideo> {
 }
 
 class _ControlsOverlay extends StatelessWidget {
-  const _ControlsOverlay({Key key, this.controller}) : super(key: key);
+  const _ControlsOverlay({Key? key, required this.controller})
+      : super(key: key);
 
   static const _examplePlaybackRates = [
     0.25,
@@ -345,7 +346,7 @@ class _PlayerVideoAndPopPage extends StatefulWidget {
 }
 
 class _PlayerVideoAndPopPageState extends State<_PlayerVideoAndPopPage> {
-  VideoPlayerController _videoPlayerController;
+  late VideoPlayerController _videoPlayerController;
   bool startedPlaying = false;
 
   @override

packages/video_player/video_player/example/pubspec.yaml

@@ -15,7 +15,7 @@ dev_dependencies:
   integration_test:
     path: ../../../integration_test
   test: any
-  pedantic: ^1.8.0
+  pedantic: ^1.10.0-nullsafety.1
 
 flutter:
   uses-material-design: true

packages/video_player/video_player/example/test_driver/integration_test.dart

@@ -2,6 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// TODO(egarciad): Remove once Flutter driver is migrated to null safety.
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';

packages/video_player/video_player/example/test_driver/video_player.dart

@@ -2,6 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// TODO(egarciad): Remove once Flutter driver is migrated to null safety.
+// @dart = 2.9
+
 import 'package:flutter_driver/driver_extension.dart';
 import 'package:video_player_example/main.dart' as app;
 

packages/video_player/video_player/example/test_driver/video_player_test.dart

@@ -2,6 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// TODO(egarciad): Remove once Flutter driver is migrated to null safety.
+// @dart = 2.9
+
 import 'dart:async';
 import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart';

packages/video_player/video_player/lib/src/closed_caption_file.dart

@@ -31,7 +31,11 @@ class Caption {
   ///
   /// This is not recommended for direct use unless you are writing a parser for
   /// a new closed captioning file type.
-  const Caption({this.number, this.start, this.end, this.text});
+  const Caption(
+      {required this.number,
+      required this.start,
+      required this.end,
+      required this.text});
 
   /// The number that this caption was assigned.
   final int number;
@@ -45,4 +49,9 @@ class Caption {
   /// The actual text that should appear on screen to be read between [start]
   /// and [end].
   final String text;
+
+  /// A no caption object. This is a caption with [start] and [end] durations of zero,
+  /// and an empty [text] string.
+  static const Caption none =
+      Caption(number: 0, start: Duration.zero, end: Duration.zero, text: '');
 }

packages/video_player/video_player/lib/src/sub_rip.dart

@@ -41,8 +41,7 @@ List<Caption> _parseCaptionsFromSubRipString(String file) {
       end: startAndEnd.end,
       text: text,
     );
-
-    if (newCaption.start != null && newCaption.end != null) {
+    if (newCaption.start != newCaption.end) {
       captions.add(newCaption);
     }
   }
@@ -64,7 +63,7 @@ class _StartAndEnd {
         RegExp(_subRipTimeStamp + _subRipArrow + _subRipTimeStamp);
 
     if (!format.hasMatch(line)) {
-      return _StartAndEnd(null, null);
+      return _StartAndEnd(Duration.zero, Duration.zero);
     }
 
     final List<String> times = line.split(_subRipArrow);
@@ -84,7 +83,7 @@ class _StartAndEnd {
 // Duration(hours: 0, minutes: 1, seconds: 59, milliseconds: 084)
 Duration _parseSubRipTimestamp(String timestampString) {
   if (!RegExp(_subRipTimeStamp).hasMatch(timestampString)) {
-    return null;
+    return Duration.zero;
   }
 
   final List<String> commaSections = timestampString.split(',');