update UI in onSharedPreferenceChangedListener in the UI thread

MyTracks/src/com/google/android/apps/mytracks/settings/BackupSettingsActivity.java

@@ -63,7 +63,12 @@ public class BackupSettingsActivity extends AbstractSettingsActivity {
                 BackupSettingsActivity.this, R.string.recording_track_id_key);
           }
           if (key != null) {
-            updateUi();
+            runOnUiThread(new Runnable() {
+                @Override
+              public void run() {
+                updateUi();
+              }
+            });
           }
         }
       };

MyTracks/src/com/google/android/apps/mytracks/settings/StatsSettingsActivity.java

@@ -47,7 +47,12 @@ public class StatsSettingsActivity extends AbstractSettingsActivity {
                 R.string.metric_units_key, PreferencesUtils.METRIC_UNITS_DEFAULT);
           }
           if (key != null) {
-            updateUi();
+            runOnUiThread(new Runnable() {
+                @Override
+              public void run() {
+                updateUi();
+              }
+            });
           }
         }
       };