Fix a bug where cards overlap when rotating the screen

Check if a certain fragment has been added before. If it's added, then
just show it instead of re-adding it again.

Bug: 118344247
Test: visual
Change-Id: I039a3a7372e163c6bcda386d2aea99e6f8c8e9b1

src/com/android/settings/homepage/SettingsHomepageActivity.java

@@ -65,7 +65,13 @@ public class SettingsHomepageActivity extends SettingsBaseActivity {
     private void showFragment(Fragment fragment, int id, String tag) {
         final FragmentManager fragmentManager = getSupportFragmentManager();
         final FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
-        fragmentTransaction.add(id, fragment, tag);
+        final Fragment showFragment = fragmentManager.findFragmentById(id);
+
+        if (showFragment == null) {
+            fragmentTransaction.add(id, fragment, tag);
+        } else {
+            fragmentTransaction.show(showFragment);
+        }
         fragmentTransaction.commit();
     }
 }