Re-enable SummaryProvider for default_activity.

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

@@ -32,6 +32,7 @@ import androidx.preference.PreferenceDialogFragmentCompat;
 
 import de.dennisguse.opentracks.R;
 import de.dennisguse.opentracks.fragments.ChooseActivityTypeDialogFragment;
+import de.dennisguse.opentracks.util.HackUtils;
 import de.dennisguse.opentracks.util.PreferencesUtils;
 import de.dennisguse.opentracks.util.TrackIconUtils;
 
@@ -57,8 +58,7 @@ public class ActivityTypePreference extends DialogPreference {
         setNegativeButtonText(android.R.string.cancel);
         setDialogIcon(null);
         setPersistent(true);
-        //TODO: for some reason the summary is not updated; after changing it. Enable summaryprovider, when fixed.
-//        setSummaryProvider(summaryProvider);
+        setSummaryProvider(summaryProvider);
     }
 
     @Override
@@ -142,6 +142,7 @@ public class ActivityTypePreference extends DialogPreference {
                 String newDefaultActivity = textView.getText().toString();
                 if (getPreference().callChangeListener(newDefaultActivity)) {
                     PreferencesUtils.setDefaultActivity(getActivity(), newDefaultActivity);
+                    HackUtils.invalidatePreference(getPreference());
                 }
             }
         }

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

@@ -13,6 +13,7 @@ import androidx.preference.PreferenceFragmentCompat;
 
 import de.dennisguse.opentracks.R;
 import de.dennisguse.opentracks.fragments.ChooseActivityTypeDialogFragment;
+import de.dennisguse.opentracks.util.HackUtils;
 import de.dennisguse.opentracks.util.PreferencesUtils;
 import de.dennisguse.opentracks.util.StringUtils;
 
@@ -190,10 +191,7 @@ public class SettingsActivity extends AppCompatActivity implements ChooseActivit
             String[] options = getResources().getStringArray(metricUnits ? R.array.stats_rate_metric_options : R.array.stats_rate_imperial_options);
             statsRatePreferences.setEntries(options);
 
-            //TODO This is a hack!!! (Alternative bring the object out of view).
-            //Need to trigger androidx.preference.preferences.notifyChanged() to trigger a redraw, but method is protected.
-            statsRatePreferences.setEnabled(false);
-            statsRatePreferences.setEnabled(true);
+            HackUtils.invalidatePreference(statsRatePreferences);
         }
     }
 }

src/main/java/de/dennisguse/opentracks/util/HackUtils.java

@@ -0,0 +1,22 @@
+package de.dennisguse.opentracks.util;
+
+import androidx.annotation.NonNull;
+import androidx.preference.Preference;
+
+public class HackUtils {
+
+    private HackUtils() {
+    }
+
+    /**
+     * Triggers a redraw of the summary of a preference if it was set programmatically.
+     * Need to trigger androidx.preference.preferences.notifyChanged() to trigger a redraw, but method is protected.
+     * This workaround also works when this preference has not changed, but it's entries (see R.string.stats_rate_key).
+     * TODO
+     */
+    public static void invalidatePreference(@NonNull Preference preference) {
+        boolean isEnabled = preference.isEnabled();
+        preference.setEnabled(!isEnabled);
+        preference.setEnabled(isEnabled);
+    }
+}