[shared_preferences] Adds Shared preferences as option in shared preferences async android (#7994)

Adds the ability to select which Android preferences backend (SharedPreferences or DataStore Preferences) one would like to use.

Also adds the ability to pick a file name for the shared preferences backend.

fixes flutter/flutter#153300
fixes flutter/flutter#14337

Author: tarrinneal

packages/shared_preferences/shared_preferences_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.4.0
+
+* Adds `SharedPreferences` support within `SharedPreferencesAsyncAndroid` API.
+
 ## 2.3.4
 
 * Restrict types when decoding preferences.

packages/shared_preferences/shared_preferences_android/README.md

@@ -11,5 +11,22 @@ so you do not need to add it to your `pubspec.yaml`.
 However, if you `import` this package to use any of its APIs directly, you
 should add it to your `pubspec.yaml` as usual.
 
+## Options
+
+The [SharedPreferencesAsync] and [SharedPreferencesWithCache] APIs can use [DataStore Preferences](https://developer.android.com/topic/libraries/architecture/datastore) or [Android SharedPreferences](https://developer.android.com/reference/android/content/SharedPreferences) to store data.
+
+To use the `Android SharedPreferences` backend, use the `SharedPreferencesAsyncAndroidOptions` when using [SharedPreferencesAsync].
+
+<?code-excerpt "example/lib/main.dart (Android_Options)"?>
+```dart
+const SharedPreferencesAsyncAndroidOptions options =
+    SharedPreferencesAsyncAndroidOptions(
+        backend: SharedPreferencesAndroidBackendLibrary.SharedPreferences,
+        originalSharedPreferencesOptions: AndroidSharedPreferencesStoreOptions(
+            fileName: 'the_name_of_a_file'));
+```
+
+The [SharedPreferences] API uses the native [Android SharedPreferences](https://developer.android.com/reference/android/content/SharedPreferences) tool to store data.
+
 [1]: https://pub.dev/packages/shared_preferences
 [2]: https://flutter.dev/to/endorsed-federated-plugin

packages/shared_preferences/shared_preferences_android/android/build.gradle

@@ -60,7 +60,8 @@ android {
     }
     dependencies {
         implementation 'androidx.datastore:datastore:1.0.0'
-        implementation 'androidx.datastore:datastore-preferences:1.0.0'    
+        implementation 'androidx.datastore:datastore-preferences:1.0.0'
+        implementation 'androidx.preference:preference:1.2.1'
         testImplementation 'junit:junit:4.13.2'
         testImplementation 'androidx.test:core-ktx:1.5.0'
         testImplementation 'androidx.test.ext:junit-ktx:1.2.1'

packages/shared_preferences/shared_preferences_android/android/gradle.properties

@@ -0,0 +1,3 @@
+org.gradle.jvmargs=-Xmx4G
+android.useAndroidX=true
+android.enableJetifier=true