[sensor] Support v2 android embedder.

packages/connectivity/ios/Classes/ConnectivityPlugin.m

@@ -155,7 +155,9 @@ - (NSString*)convertCLAuthorizationStatusToString:(CLAuthorizationStatus)status
     case kCLAuthorizationStatusAuthorizedWhenInUse: {
       return @"authorizedWhenInUse";
     }
-    default: { return @"unknown"; }
+    default: {
+      return @"unknown";
+    }
   }
 }
 

packages/sensors/android/build.gradle

@@ -64,10 +64,9 @@ afterEvaluate {
         android {
             dependencies {
                 def lifecycle_version = "2.1.0"
-
-                compileOnly "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
-                compileOnly "androidx.lifecycle:lifecycle-runtime:$lifecycle_version"
+                api "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
+                api "androidx.lifecycle:lifecycle-runtime:$lifecycle_version"
             }
         }
     }
-}
+}

packages/sensors/android/gradle.properties

@@ -1,4 +1 @@
 org.gradle.jvmargs=-Xmx1536M
-android.enableR8=true
-android.useAndroidX=true
-android.enableJetifier=true

packages/sensors/android/src/main/java/io/flutter/plugins/sensors/SensorsPlugin.java

@@ -32,15 +32,13 @@ public static void registerWith(Registrar registrar) {
 
   @Override
   public void onAttachedToEngine(FlutterPluginBinding binding) {
-    Context context = binding.getApplicationContext();
+    final Context context = binding.getApplicationContext();
     setupEventChannels(context, binding.getFlutterEngine().getDartExecutor());
   }
 
   @Override
   public void onDetachedFromEngine(FlutterPluginBinding binding) {
-    accelerometerChannel.setStreamHandler(null);
-    userAccelChannel.setStreamHandler(null);
-    gyroscopeChannel.setStreamHandler(null);
+    teardownEventChannels();
   }
 
   private void setupEventChannels(Context context, BinaryMessenger messenger) {
@@ -65,4 +63,10 @@ private void setupEventChannels(Context context, BinaryMessenger messenger) {
             Sensor.TYPE_GYROSCOPE);
     gyroscopeChannel.setStreamHandler(gyroScopeStreamHandler);
   }
+
+  private void teardownEventChannels() {
+    accelerometerChannel.setStreamHandler(null);
+    userAccelChannel.setStreamHandler(null);
+    gyroscopeChannel.setStreamHandler(null);
+  }
 }

packages/sensors/example/android/app/src/main/AndroidManifest.xml

@@ -12,7 +12,6 @@
                   android:windowSoftInputMode="adjustResize">
         </activity>
         <activity android:name=".MainActivity"
-            android:launchMode="singleTop"
             android:theme="@android:style/Theme.Black.NoTitleBar"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection"
             android:hardwareAccelerated="true"