[ android_alarm_manager ] Loosen Flutter SDK lower bound, update READ…

…ME (#2338)

packages/android_alarm_manager/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.4.5+1
+
+* Loosen Flutter version restriction to 1.9.1. **NOTE: plugin registration
+  for the background isolate will not work correctly for applications using the
+  V2 Flutter Android embedding for Flutter versions lower than 1.12.**
+
 ## 0.4.5
 
 * Add support for Flutter Android embedding V2

packages/android_alarm_manager/README.md

@@ -59,11 +59,21 @@ will not run in the same isolate as the main application. Unlike threads, isolat
 memory and communication between isolates must be done via message passing (see more documentation on
 isolates [here](https://api.dart.dev/stable/2.0.0/dart-isolate/dart-isolate-library.html)).
 
+
+## Using other plugins in alarm callbacks
+
 If alarm callbacks will need access to other Flutter plugins, including the
-alarm manager plugin itself, it is necessary to teach the background service how
-to initialize plugins. This is done by giving the `AlarmService` a callback to call
-in the application's `onCreate` method. See the example's
+alarm manager plugin itself, it may be necessary to inform the background service how
+to initialize plugins depending on which Flutter Android embedding the application is
+using.
+
+### Flutter Android Embedding V1
+
+For the Flutter Android Embedding V1, the background service must be provided a
+callback to register plugins with the background isolate. This is done by giving
+the `AlarmService` a callback to call the application's `onCreate` method. See the example's
 [Application overrides](https://github.com/flutter/plugins/blob/master/packages/android_alarm_manager/example/android/app/src/main/java/io/flutter/plugins/androidalarmmanagerexample/Application.java).
+
 In particular, its `Application` class is as follows:
 
 ```java
@@ -92,6 +102,17 @@ Which must be reflected in the application's `AndroidManifest.xml`. E.g.:
 **Note:** Not calling `AlarmService.setPluginRegistrant` will result in an exception being
 thrown when an alarm eventually fires.
 
+### Flutter Android Embedding V2 (Flutter Version >= 1.12)
+
+For the Flutter Android Embedding V2, plugins are registered with the background
+isolate via reflection so `AlarmService.setPluginRegistrant` does not need to be
+called.
+
+**NOTE: this plugin is not completely compatible with the V2 embedding on
+Flutter versions < 1.12 as the background isolate will not automatically
+register plugins. This can be resolved by running `flutter upgrade` to upgrade
+to the latest Flutter version.**
+
 For help getting started with Flutter, view our online
 [documentation](http://flutter.io/).
 

packages/android_alarm_manager/pubspec.yaml

@@ -1,7 +1,7 @@
 name: android_alarm_manager
 description: Flutter plugin for accessing the Android AlarmManager service, and
   running Dart code in the background when alarms fire.
-version: 0.4.5
+version: 0.4.5+1
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/android_alarm_manager
 
@@ -22,5 +22,4 @@ flutter:
 
 environment:
   sdk: ">=2.0.0-dev.28.0 <3.0.0"
-  # TODO(bkonyi): set minimum Flutter version to next stable release
-  flutter: ">=1.2.0 <2.0.0"
+  flutter: ">=1.9.1 <2.0.0"