Alert

GlassAlert is iOS 26's alert: a 320 px glass panel with 34 px corners, a title, an optional message and capsule action buttons. You show it with showGlassDialog, which pushes it on the navigator, centred over a 20% black dim, and returns a Future with the value the alert was closed with.

The alert materializes in: blur first, tint last, with the text fading in on top. It lifts itself above page glass and glass bars, so you don't need a GlassAbove for it.

When to use

• Short confirmations and destructive-action prompts: "Delete this photo?", "Discard changes?".
• A message the user must acknowledge before going on.
• Not for forms, pickers or anything long. Use a sheet.
• Not for a list of actions on an item. Use a menu.

Usage

final bool? delete = await showGlassDialog<bool>(
  context: context,
  builder: (BuildContext context) => GlassAlert(
    title: const Text('Delete "Lisbon.jpg"?'),
    message: const Text('This cannot be undone.'),
    actions: <GlassAlertAction>[
      GlassAlertAction(label: 'Cancel', onPressed: () => Navigator.pop(context, false)),
      GlassAlertAction(label: 'Delete', isDestructive: true, onPressed: () => Navigator.pop(context, true)),
    ],
  ),
);

Behaviour

• Exactly two actions sit side by side. One, or three and more, are stacked.
• isDefault draws an action's label bold; isDestructive draws it in iOS red. onPressed: null disables it.
• The title is 17 px semibold, the message 15 px at 60% of the label colour. Both start-aligned by default; pass textAlign: TextAlign.center to your Texts for the centred iOS look.
• The panel is 320 px wide, or the screen width less 16 px on each side when that is narrower.
• By default a tap on the dim does nothing, as in iOS. Set barrierDismissible: true to let it close the alert; the Future then completes with null.

Setup

Accessibility

• The dim is announced with barrierLabel ("Dismiss" by default) when it can close the alert.
• Keep action labels short verbs ("Delete", "Keep"), not "Yes" and "No".

Code

import 'package:flutter/material.dart';
import 'package:g1455/g1455.dart';

/// A row that asks before deleting its file.
/// Assumes a GlassHost above the navigator, e.g. in MaterialApp.builder.
class FileTile extends StatefulWidget {
  const FileTile({required this.name, required this.onDelete, super.key});

  final String name;
  final VoidCallback onDelete;

  @override
  State<FileTile> createState() => _FileTileState();
}

class _FileTileState extends State<FileTile> {
  Future<void> _confirm() async {
    final bool? delete = await showGlassDialog<bool>(
      context: context,
      builder: (BuildContext context) => GlassAlert(
        title: Text('Delete "${widget.name}"?', textAlign: TextAlign.center),
        message: const Text('It will be removed from all your devices.', textAlign: TextAlign.center),
        actions: <GlassAlertAction>[
          // Actions don't close the alert: pop with the answer.
          GlassAlertAction(label: 'Cancel', onPressed: () => Navigator.pop(context, false)),
          GlassAlertAction(label: 'Delete', isDestructive: true, onPressed: () => Navigator.pop(context, true)),
        ],
      ),
    );
    if (delete ?? false) {
      widget.onDelete();
    }
  }

  @override
  Widget build(BuildContext context) => ListTile(
    leading: const Icon(Icons.image_outlined),
    title: Text(widget.name),
    trailing: GlassButton(
      onPressed: _confirm,
      semanticLabel: 'Delete ${widget.name}',
      padding: EdgeInsets.zero,
      child: const Icon(Icons.delete_outline),
    ),
  );
}

API

showGlassDialog<T>

GlassAlert

GlassAlertAction

Constants