enable null safety

Author: zihejia

.github/workflows/flutter.yml

@@ -16,7 +16,7 @@ jobs:
         java-version: '12.x'
     - uses: subosito/flutter-action@v1
       with:
-        flutter-version: '1.22.4'
+        flutter-version: '2.0.3'
     - run: flutter pub get
     - run: flutter test
     - run: flutter analyze --no-pub --no-current-package lib

example/lib/analytics.dart

@@ -2,14 +2,14 @@ import 'package:mixpanel_flutter/mixpanel_flutter.dart';
 
 class MixpanelManager {
 
-  static Mixpanel _instance;
+  static Mixpanel? _instance;
 
   static Future<Mixpanel> init() async {
     if (_instance == null) {
       _instance = await Mixpanel.init("Your Mixpanel Token",
           optOutTrackingDefault: false);
     }
-    return _instance;
+    return _instance!;
   }
 
 }

example/lib/event.dart

@@ -11,10 +11,10 @@ class EventScreen extends StatefulWidget {
 }
 
 class _EventScreenState extends State<EventScreen> {
-  Mixpanel _mixpanel;
+  late final Mixpanel _mixpanel;
 
   @override
-  Future<void> initState() {
+  initState() {
     super.initState();
     _initMixpanel();
   }

example/lib/gdpr.dart

@@ -9,7 +9,7 @@ class GDPRScreen extends StatefulWidget {
 }
 
 class _GDPRScreenState extends State<GDPRScreen> {
-  Mixpanel _mixpanel;
+  late final Mixpanel _mixpanel;
 
   @override
   void initState() {

example/lib/group.dart

@@ -9,8 +9,8 @@ class GroupScreen extends StatefulWidget {
 }
 
 class _GroupScreenState extends State<GroupScreen> {
-  Mixpanel _mixpanel;
-  MixpanelGroup _mixpanelGroup;
+  late final Mixpanel _mixpanel;
+  late final MixpanelGroup _mixpanelGroup;
 
   @override
   void initState() {

example/lib/profile.dart

@@ -9,7 +9,7 @@ class ProfileScreen extends StatefulWidget {
 }
 
 class _ProfileScreenState extends State<ProfileScreen> {
-  Mixpanel _mixpanel;
+  late final Mixpanel _mixpanel;
 
   @override
   void initState() {

example/lib/widget.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 
 class MixpanelButton extends StatelessWidget {
-  MixpanelButton({@required this.onPressed, @required this.text});
+  MixpanelButton({required this.onPressed, required this.text});
   final GestureTapCallback onPressed;
   final String text;
 

example/pubspec.lock

@@ -7,42 +7,42 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.1"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.3"
+    version: "1.15.0"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -56,7 +56,7 @@ packages:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -73,28 +73,28 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.1"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   mixpanel_flutter:
     dependency: "direct main"
     description:
       path: ".."
       relative: true
     source: path
-    version: "1.0.0"
+    version: "1.0.1"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.1"
+    version: "1.8.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -106,56 +106,56 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.2"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.1"
+    version: "1.10.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.2"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.10.0-110 <2.11.0"
+  dart: ">=2.12.0 <3.0.0"
   flutter: ">=1.20.0"

example/pubspec.yaml

@@ -4,7 +4,7 @@ description: Demonstrates how to use the mixpanel_flutter plugin.
 publish_to: 'none'
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:

lib/mixpanel_flutter.dart

@@ -11,13 +11,12 @@ class Mixpanel {
     'mp_lib': 'flutter',
   };
 
-  String _token;
-  People _people;
+  final String _token;
+  final People _people;
 
-  Mixpanel(String token) {
-    this._token = token;
-    this._people = new People(token);
-  }
+  Mixpanel(String token)
+      : _token = token,
+        _people = new People(token);
 
   ///
   ///  Initializes an instance of the API with the given project token.
@@ -30,10 +29,7 @@ class Mixpanel {
       {bool optOutTrackingDefault = false}) async {
     var properties = <String, dynamic>{'token': token};
 
-    if (optOutTrackingDefault != null) {
-      properties['optOutTrackingDefault'] = optOutTrackingDefault;
-    }
-
+    properties['optOutTrackingDefault'] = optOutTrackingDefault;
     properties['mixpanelProperties'] = _mixpanelProperties;
 
     await _channel.invokeMethod<void>('initialize', properties);
@@ -68,6 +64,7 @@ class Mixpanel {
   /// * [loggingEnabled] whether to enable logging
   void setLoggingEnabled(bool loggingEnabled) {
     if (Platform.isIOS) {
+      // ignore: unnecessary_null_comparison
       if (loggingEnabled != null) {
         _channel.invokeMethod<void>('setLoggingEnabled',
             <String, dynamic>{'loggingEnabled': loggingEnabled});
@@ -81,7 +78,7 @@ class Mixpanel {
 
   /// Will return true if the user has opted out from tracking.
   /// return true if user has opted out from tracking. Defaults to false.
-  Future<bool> hasOptedOutTracking() async {
+  Future<bool?> hasOptedOutTracking() async {
     return await _channel.invokeMethod<bool>('hasOptedOutTracking');
   }
 
@@ -101,7 +98,6 @@ class Mixpanel {
     _channel.invokeMethod<void>('optOutTracking');
   }
 
-
   /// Associate all future calls to track() with the user identified by
   /// the given distinct id.
   ///
@@ -161,7 +157,7 @@ class Mixpanel {
   ///
   /// * [eventName] The name of the event to send
   /// * [properties] An optional map containing the key value pairs of the properties to include in this event.
-  void track(String eventName, {Map<String, dynamic> properties}) {
+  void track(String eventName, {Map<String, dynamic>? properties}) {
     if (_MixpanelHelper.isValidString(eventName)) {
       _channel.invokeMethod<void>('track',
           <String, dynamic>{'eventName': eventName, 'properties': properties});
@@ -326,7 +322,7 @@ class Mixpanel {
   /// and persist beyond the lifetime of your application.
   ///
   /// return Super properties for this Mixpanel instance.
-  Future<Map> getSuperProperties() async {
+  Future<Map?> getSuperProperties() async {
     return await _channel.invokeMethod<Map>('getSuperProperties');
   }
 
@@ -360,7 +356,7 @@ class Mixpanel {
   /// * [eventName] the name of the event to be tracked that was previously called with timeEvent()
   ///
   /// Time elapsed since timeEvent(String) was called for the given eventName.
-  Future<double> eventElapsedTime(String eventName) async {
+  Future<double?> eventElapsedTime(String eventName) async {
     if (_MixpanelHelper.isValidString(eventName)) {
       return await _channel.invokeMethod<double>(
           'eventElapsedTime', <String, dynamic>{'eventName': eventName});
@@ -386,7 +382,7 @@ class Mixpanel {
   /// ```
   ///
   /// return Future<String> the distinct id associated with Mixpanel event and People Analytics
-  Future<String> getDistinctId() {
+  Future<String?> getDistinctId() {
     return _channel.invokeMethod<String>('getDistinctId');
   }
 
@@ -413,11 +409,9 @@ class Mixpanel {
 class People {
   static const MethodChannel _channel = const MethodChannel('mixpanel_flutter');
 
-  String _token;
+  final String _token;
 
-  People(String token) {
-    this._token = token;
-  }
+  People(String token) : _token = token;
 
   /// Sets a single property with the given name and value for this user.
   /// The given name and value will be assigned to the user in Mixpanel People Analytics,
@@ -554,7 +548,8 @@ class People {
   ///
   /// * [amount] the amount of money exchanged. Positive amounts represent purchases or income from the customer, negative amounts represent refunds or payments to the customer.
   /// * [properties] an optional collection of properties to associate with this transaction.
-  void trackCharge(double amount, {Map<String, dynamic> properties}) {
+  void trackCharge(double amount, {Map<String, dynamic>? properties}) {
+    // ignore: unnecessary_null_comparison
     if (amount != null) {
       _channel.invokeMethod<void>('trackCharge', <String, dynamic>{
         'token': this._token,
@@ -589,15 +584,14 @@ class People {
 class MixpanelGroup {
   static const MethodChannel _channel = const MethodChannel('mixpanel_flutter');
 
-  String _token;
-  String _groupKey;
-  dynamic _groupID;
+  final String _token;
+  final String _groupKey;
+  final dynamic _groupID;
 
-  MixpanelGroup(String token, String groupKey, dynamic groupID) {
-    this._token = token;
-    this._groupKey = groupKey;
-    this._groupID = groupID;
-  }
+  MixpanelGroup(String token, String groupKey, dynamic groupID)
+      : _token = token,
+        _groupKey = groupKey,
+        _groupID = groupID;
 
   /// Sets a single property with the given name and value for this group.
   /// The given name and value will be assigned to the user in Mixpanel Group Analytics,
@@ -691,6 +685,7 @@ class MixpanelGroup {
           name: 'Mixpanel');
       return;
     }
+    // ignore: unnecessary_null_comparison
     if (value == null) {
       developer.log('`group union` failed: value cannot be blank',
           name: 'Mixpanel');
@@ -708,6 +703,7 @@ class MixpanelGroup {
 
 class _MixpanelHelper {
   static isValidString(String input) {
+    // ignore: unnecessary_null_comparison
     return input != null && input.isNotEmpty;
   }
 }