More robust handling for nav controller

Author: Futsch1

app/src/main/java/com/futsch1/medtimer/MainActivity.java

@@ -155,8 +155,12 @@ protected void onNewIntent(Intent intent) {
 
     @Override
     public boolean onSupportNavigateUp() {
-        NavController navController = findNavController(this, R.id.navHost);
-        return NavigationUI.navigateUp(navController, appBarConfiguration)
-                || super.onSupportNavigateUp();
+        try {
+            NavController navController = findNavController(this, R.id.navHost);
+            return NavigationUI.navigateUp(navController, appBarConfiguration)
+                    || super.onSupportNavigateUp();
+        } catch (IllegalStateException e) {
+            return false;
+        }
     }
 }

app/src/main/java/com/futsch1/medtimer/OptionsMenu.java

@@ -105,8 +105,12 @@ private static void enableOptionalIcons(@NonNull Menu menu) {
     private void setupSettings() {
         MenuItem item = menu.findItem(R.id.settings);
         item.setOnMenuItemClickListener(menuItem -> {
-            Navigation.findNavController(view).navigate(R.id.action_global_preferencesFragment);
-            return true;
+            try {
+                Navigation.findNavController(view).navigate(R.id.action_global_preferencesFragment);
+                return true;
+            } catch (IllegalStateException e) {
+                return false;
+            }
         });
     }