Recording without GPS: show a Snackbar to warn user that recording is not using GPS.

src/main/res/values/colors.xml

@@ -42,4 +42,5 @@ limitations under the License.
     <color name="track_controller_background_activated">#3F0000</color>
 
     <color name="splashscreen_background">#272727</color>
+
 </resources>

src/main/res/values/strings.xml

@@ -244,12 +244,15 @@ limitations under the License.
     <string name="generic_to">To</string>
     <string name="generic_today">Today</string>
     <string name="generic_yesterday">Yesterday</string>
+    <string name="generic_dismiss">Dismiss</string>
     <!-- Gps -->
     <string name="gps_starting">Starting GPS</string>
     <string name="gps_wait_for_better_signal">Waiting for a better GPS signal</string>
     <string name="gps_wait_for_signal">Waiting for GPS signal</string>
     <string name="gps_disabled_msg">GPS disabled</string>
     <string name="gps_fixed_and_ready">GPS fixed and ready</string>
+    <string name="gps_recording_status">%1$s: %2$s</string>
+    <string name="gps_recording_without_signal">OpenTracks is recording without GPS data.</string>
     <!-- Image -->
     <string name="image_arrow">Arrow</string>
     <string name="image_marker">Marker</string>

src/main/res/values/styles.xml

@@ -333,4 +333,29 @@ limitations under the License.
         <item name="cardPreventCornerOverlap">true</item>
         <item name="cardUseCompatPadding">true</item>
     </style>
+
+    <!-- Snackbar -->
+    <style name="MaterialSnackbarTheme" parent="@style/Widget.MaterialComponents.Snackbar">
+        <item name="materialThemeOverlay">@style/ThemeOverlay.App.Snackbar</item>
+        <item name="actionTextColorAlpha">1</item>
+
+        <item name="backgroundTint">@android:color/holo_red_dark</item>
+    </style>
+
+    <style name="MaterialSnackbarTextButtonTheme" parent="@style/Widget.MaterialComponents.Button.TextButton.Snackbar">
+        <item name="android:textColor">@android:color/white</item>
+        <item name="android:textSize">14sp</item>
+    </style>
+
+    <style name="MaterialSnackbarTextViewTheme" parent="@style/Widget.MaterialComponents.Snackbar.TextView">
+        <item name="android:textColor">@android:color/white</item>
+        <item name="android:textAppearance">?textAppearanceLabelMedium</item>
+        <item name="android:textSize">14sp</item>
+    </style>
+
+    <style name="ThemeOverlay.App.Snackbar" parent="">
+        <item name="colorSurface">@android:color/holo_red_dark</item>
+        <item name="colorOnSurface">@android:color/holo_red_dark</item>
+    </style>
+
 </resources>

src/main/res/values/themes_custom.xml

@@ -23,6 +23,12 @@ limitations under the License.
         <item name="android:activatedBackgroundIndicator">@drawable/activated_background</item>
 
         <item name="windowActionModeOverlay">true</item>
+
+        <!-- Snackbar -->
+        <item name="snackbarStyle">@style/MaterialSnackbarTheme</item>
+        <item name="snackbarButtonStyle">@style/MaterialSnackbarTextButtonTheme</item>
+        <item name="snackbarTextViewStyle">@style/MaterialSnackbarTextViewTheme</item>
+
     </style>
 
     <style name="SplashTheme" parent="ThemeCustom">