GainManager should only re-connect if sensor should be changed.

src/main/java/de/dennisguse/opentracks/sensors/SensorHandler.java

@@ -1,7 +1,6 @@
 package de.dennisguse.opentracks.sensors;
 
 import android.content.Context;
-import android.content.SharedPreferences;
 import android.os.Handler;
 
 import androidx.annotation.NonNull;
@@ -17,8 +16,6 @@ public abstract class SensorHandler<T> {
 
     private final SensorManager sensorManager;
 
-    private final SharedPreferences.OnSharedPreferenceChangeListener sharedPreferenceChangeListener = (sharedPreferences, key) -> connect();
-
     private Context context;
     private Handler handler;
     private Driver driver;
@@ -48,7 +45,6 @@ public abstract class SensorHandler<T> {
         }
     };
 
-
     protected SensorHandler(SensorManager sensorManager) {
         this.sensorManager = sensorManager;
     }
@@ -57,13 +53,11 @@ public abstract class SensorHandler<T> {
     void start(Context context, Handler handler) {
         this.context = context;
         this.handler = handler;
-        PreferencesUtils.registerOnSharedPreferenceChangeListener(sharedPreferenceChangeListener);
     }
 
     void stop() {
         this.context = null;
         this.handler = null;
-        PreferencesUtils.unregisterOnSharedPreferenceChangeListener(sharedPreferenceChangeListener);
 
         disconnect();
     }
@@ -109,6 +103,8 @@ public abstract class SensorHandler<T> {
     @NonNull
     protected abstract Aggregator<T, ?> createAggregator();
 
+    protected abstract int getSensorPreferenceKey();
+
     protected Context getContext() {
         return context;
     }

src/main/java/de/dennisguse/opentracks/sensors/SensorManager.java

@@ -167,6 +167,10 @@ public class SensorManager implements SharedPreferences.OnSharedPreferenceChange
         if (gpsManager != null) {
             gpsManager.onSharedPreferenceChanged(sharedPreferences, key);
 
+            if (PreferencesUtils.isKey(altitudeSumManager.getSensorPreferenceKey(), key)) {
+                altitudeSumManager.connect();
+            }
+
             if (PreferencesUtils.isKey(R.string.settings_sensor_bluetooth_heart_rate_key, key)) {
                 String address = PreferencesUtils.getBluetoothHeartRateSensorAddress();
                 connect(heartRateManager, address);