Add backup rules for newer apis

Author: cbalster

app/src/main/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+<manifest xmlns:tools="http://schemas.android.com/tools"
+    xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
@@ -28,10 +29,12 @@
         android:name=".App"
         android:allowBackup="true"
         android:fullBackupContent="@xml/backup_descriptor"
+        android:dataExtractionRules="@xml/data_extraction_rules"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
-        android:supportsRtl="true">
+        android:supportsRtl="true"
+        tools:targetApi="s">
 
         <activity
             android:name="de.stephanlindauer.criticalmaps.Main"

app/src/main/res/xml/data_extraction_rules.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<data-extraction-rules>
+    <!-- only backup our sharedprefs-->
+    <cloud-backup>
+        <include
+            domain="sharedpref"
+            path="Main.xml" />
+    </cloud-backup>
+    <device-transfer>
+        <include
+            domain="sharedpref"
+            path="Main.xml" />
+    </device-transfer>
+</data-extraction-rules>