The Hidden SnackBar Problem in Flutter

We’ve all had those moments as developers.

You click a button, an API call fails, your code executes exactly as expected… and yet nothing happens on the screen.

That was me a few weeks ago.

I was working on a Settings screen in a Flutter application. Nothing unusual — just the typical features every app eventually needs:

• Change Password
• Change Language
• Delete Account
• Logout

To keep the experience clean, each action opened a custom popup using showGeneralDialog(). The dialogs looked great, the animations were smooth, and everything felt polished.

Until I tested an API failure. The backend returned an error.

The debugger confirmed that my SnackBar code had executed.

But there was one problem. The SnackBar never appeared.

Or at least… that’s what I thought.

The Bug That Wasn’t Really a Bug

My first instinct was the same one most Flutter developers probably have.

“Did I use the wrong BuildContext?"

So I tried another context. Still nothing. Maybe the ScaffoldMessenger wasn't available?

I switched to a global ScaffoldMessengerKey.

Nothing. I even wondered if Flutter had a bug with showGeneralDialog().

After spending far longer than I’d like to admit debugging it, I finally discovered something surprisingly simple.

The SnackBar was being shown. It was just hiding behind the dialog.

The Setup

The code looked familiar. Opening the dialog:

showGeneralDialog(
  context: context,
  pageBuilder: (_, __, ___) => const ChangePasswordDialog(),
);

Inside the dialog, the user submits the form. If the API fails:

ScaffoldMessenger.of(context).showSnackBar(
  const SnackBar(
    content: Text("Unable to change password"),
  ),
);

The code executes. The SnackBar is created. Yet the user never sees it.

At first glance, it feels like Flutter is ignoring your request. But Flutter is actually doing exactly what you asked.

The Missing Piece: Routes

The breakthrough came when I stopped looking at widgets and started thinking about routes.

Like many developers, I subconsciously thought of dialogs as floating widgets placed above the current screen.

That’s not how showGeneralDialog() works.

Internally, Flutter pushes a new RawDialogRoute onto the Navigator.

Instead of looking like this:

Scaffold
 ├── Screen
 └── Dialog

it’s actually more like this:

Navigator
│
├── Home Route
│     └── Scaffold
│          └── Screen
│
└── RawDialogRoute
      └── Dialog

That tiny detail changes everything. The dialog isn’t part of your screen.

It’s an entirely separate route sitting above it.

So Where Does the SnackBar Go?

This is the part that finally made everything click for me. A SnackBar doesn't belong to the dialog. It belongs to the ScaffoldMessenger.

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And the ScaffoldMessenger belongs to the Home Route.

So Flutter paints the UI like this:

Top
──────────────────────
Dialog (RawDialogRoute)
──────────────────────
SnackBar
──────────────────────
Home Screen
Bottom

The SnackBar isn’t missing. It isn’t failing. It isn’t using the wrong context.

It’s simply being rendered underneath a route that’s covering it.

Once I understood that, the behavior suddenly made perfect sense.

My First “Fix” Wasn’t Actually a Fix

Like many developers, I initially tried changing the context.

ScaffoldMessenger.of(dialogContext)

Then:

ScaffoldMessenger.of(rootContext)

Then a global key. None of those solved the real problem.

Because the issue wasn’t where I was calling showSnackBar().

The issue was which route owned the SnackBar.

Sometimes we spend hours debugging code that’s technically correct, simply because we misunderstand how the framework works internally.

What Worked

Depending on the situation, I found three approaches.

1. Close the dialog first

If the dialog doesn’t need to stay open, dismiss it before showing the SnackBar.

Navigator.pop(context);

ScaffoldMessenger.of(parentContext).showSnackBar(
  const SnackBar(
    content: Text("Password updated"),
  ),
);

Simple. Effective.

2. Show the error inside the dialog

This ended up being my preferred solution. Think about it from the user’s perspective.

If they’re changing their password and the server says the current password is incorrect, does it really make sense to close the dialog and show a SnackBar?

Probably not. Keeping the dialog open and displaying the error inline creates a much smoother experience.

3. Use an overlay

For global notifications that should appear regardless of what’s on the screen, overlay-based solutions like another_flushbar, top_snackbar_flutter, or fluttertoast can render above dialogs.

The Bigger Lesson

This experience reminded me of something I love about Flutter.

Many of the “bugs” we encounter aren’t bugs at all. They’re opportunities to understand the framework a little better.

The more you understand concepts like routes, overlays, and the rendering order, the less time you’ll spend chasing mysterious UI issues.

And the next time someone on your team says,

“The SnackBar isn’t showing.”

You’ll probably smile and ask,

“Is there a dialog open?”

Final Thoughts

Flutter wasn’t hiding my SnackBar.

It was teaching me how its navigation system works. Sometimes the best debugging sessions aren’t the ones where you fix the code.

They’re the ones where you leave with a better mental model of the framework. And in my experience, those lessons stick with you far longer than any Stack Overflow answer ever will.

Have you ever spent hours debugging something that turned out to be Flutter behaving exactly as designed? I’d love to hear your story in the comments.