Moved the code from activity to ViewModel. Minor layout updates.

app/src/main/res/drawable/ic_refresh.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FFFFFF"
+        android:pathData="M17.65,6.35C16.2,4.9 14.21,4 12,4c-4.42,0 -7.99,3.58 -7.99,8s3.57,8 7.99,8c3.73,0 6.84,-2.55 7.73,-6h-2.08c-0.82,2.33 -3.04,4 -5.65,4 -3.31,0 -6,-2.69 -6,-6s2.69,-6 6,-6c1.66,0 3.14,0.69 4.22,1.78L13,11h7V4l-2.35,2.35z" />
+</vector>

app/src/main/res/layout/app_bar_main.xml

@@ -18,16 +18,16 @@
             <androidx.constraintlayout.widget.ConstraintLayout
                 android:id="@+id/timer_layout"
                 android:layout_width="match_parent"
-                android:layout_height="wrap_content"
-                android:layout_marginEnd="16dp">
+                android:layout_height="wrap_content">
 
                 <TextView
                     android:id="@+id/time_to_aos"
                     android:layout_width="0dp"
                     android:layout_height="wrap_content"
+                    android:layout_marginEnd="16dp"
                     android:gravity="center"
                     android:text="@string/next_aos_pattern"
-                    android:textSize="32sp"
+                    android:textSize="30sp"
                     app:layout_constraintBottom_toBottomOf="parent"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"

app/src/main/res/menu/main_menu.xml

@@ -1,21 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
-<menu xmlns:android="http://schemas.android.com/apk/res/android">
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
     <item
-        android:id="@+id/fetch_trans"
-        android:title="@string/menu_fetch_transmitters" />
-    <item
-        android:id="@+id/save_to_db"
-        android:title="@string/menu_save_to_db" />
-    <item
-        android:id="@+id/load_from_db"
-        android:title="@string/menu_load_from_db" />
-    <item
-        android:id="@+id/fetch_tle"
-        android:title="@string/menu_fetch_tle" />
-    <item
-        android:id="@+id/load_tle"
-        android:title="@string/menu_load_tle" />
-    <item
-        android:id="@+id/action_exit"
-        android:title="@string/menu_exit" />
+        android:id="@+id/menu_refresh"
+        android:icon="@drawable/ic_refresh"
+        android:title="@string/menu_refresh"
+        app:showAsAction="always" />
 </menu>

app/src/main/res/values/strings.xml

@@ -19,12 +19,7 @@
     <string name="height">Height AMSL: </string>
     <string name="height_def">48.0m</string>
 
-    <string name="menu_fetch_transmitters">Fetch Transmitters</string>
-    <string name="menu_save_to_db">Save to DB</string>
-    <string name="menu_load_from_db">Load from DB</string>
-    <string name="menu_fetch_tle">Fetch TLE</string>
-    <string name="menu_load_tle">Load TLE</string>
-    <string name="menu_exit">Exit</string>
+    <string name="menu_refresh">Refresh</string>
 
     <string name="next_aos_pattern">AOS in %02d:%02d:%02d</string>
     <string name="drawer_locator">Drawer Locator</string>