Bugfix: crash if heart rate sensor was null (i.e., preference not initialized).

fastlane/metadata/android/en-US/changelogs/3162.txt

@@ -6,4 +6,5 @@ Changes:
 Bugfixes:
 - Export via KMZ did not export picture filenames correctly
 - Sharing multiple tracks did not include KMZ files
-- MarkerDetailActivity's UI was not shown
+- MarkerDetailActivity's UI was not shown
+- Settings crashed if preference of heart rate was not initialized

src/main/java/de/dennisguse/opentracks/settings/BluetoothLePreference.java

@@ -147,7 +147,7 @@ public class BluetoothLePreference extends DialogPreference {
 
             BluetoothLePreference preference = (BluetoothLePreference) getPreference();
             String deviceSelected = preference.getValue();
-            if (!deviceNone.equals(deviceSelected)) {
+            if (deviceSelected != null && !deviceNone.equals(deviceSelected)) {
                 listAdapter.add(preference.getValue(), preference.getValue());
                 selectedEntryIndex = 1;
             }