Alerts

Introduction

Nylo Website provides a toast notification system for displaying alerts to users. It ships with four built-in styles -- success, warning, info, and danger -- and supports custom styles through a registry pattern.

Alerts can be triggered from pages, controllers, or anywhere you have a BuildContext.

Basic Usage

Show a toast notification using convenience methods in any NyState page:

// Success toast
showToastSuccess(description: "Item saved successfully");

// Warning toast
showToastWarning(description: "Your session is about to expire");

// Info toast
showToastInfo(description: "New version available");

// Danger toast
showToastDanger(description: "Failed to save item");

Or use the global function with a style ID:

showToastNotification(context, id: "success", description: "Item saved!");

Built-in Styles

Nylo Website registers four default toast styles:

These are configured in lib/config/toast_notification.dart:

class ToastNotificationConfig {
  static final Map<String, ToastStyleFactory> styles = {
    'success': ToastNotification.style(
      icon: Icon(Icons.check_circle, color: Colors.green, size: 20),
      color: Colors.green.shade50,
      defaultTitle: 'Success',
    ),
    'warning': ToastNotification.style(
      icon: Icon(Icons.warning_amber_rounded, color: Colors.orange, size: 20),
      color: Colors.orange.shade50,
      defaultTitle: 'Warning',
    ),
    'info': ToastNotification.style(
      icon: Icon(Icons.info_outline, color: Colors.teal, size: 20),
      color: Colors.teal.shade50,
      defaultTitle: 'Info',
    ),
    'danger': ToastNotification.style(
      icon: Icon(Icons.warning_rounded, color: Colors.red, size: 20),
      color: Colors.red.shade50,
      defaultTitle: 'Error',
    ),
  };
}

Showing Alerts from Pages

In any page extending NyState or NyBaseState, use these convenience methods:

class _MyPageState extends NyState<MyPage> {

  void onSave() {
    // Success
    showToastSuccess(description: "Saved!");

    // With custom title
    showToastSuccess(title: "Done", description: "Your profile was updated.");

    // Warning
    showToastWarning(description: "Check your input");

    // Info
    showToastInfo(description: "Tip: Swipe left to delete");

    // Danger
    showToastDanger(description: "Something went wrong");

    // Oops (uses danger style)
    showToastOops(description: "That didn't work");

    // Sorry (uses danger style)
    showToastSorry(description: "We couldn't process your request");

    // Custom style by ID
    showToastCustom(id: "custom", description: "Custom alert!");
  }
}

General Toast Method

showToast(
  id: 'success',
  title: 'Hello',
  description: 'Welcome back!',
  duration: Duration(seconds: 3),
);

Showing Alerts from Controllers

Controllers extending NyController have the same convenience methods:

class ProfileController extends NyController {
  void updateProfile() async {
    try {
      await api.updateProfile();
      showToastSuccess(description: "Profile updated");
    } catch (e) {
      showToastDanger(description: "Failed to update profile");
    }
  }
}

Available methods: showToastSuccess, showToastWarning, showToastInfo, showToastDanger, showToastOops, showToastSorry, showToastCustom.

showToastNotification

The global showToastNotification() function displays a toast from anywhere you have a BuildContext:

showToastNotification(
  context,
  id: 'success',
  title: 'Saved',
  description: 'Your changes have been saved.',
  duration: Duration(seconds: 3),
  position: ToastNotificationPosition.top,
  action: () {
    // Called when the toast is tapped
    routeTo("/details");
  },
  onDismiss: () {
    // Called when the toast is dismissed
  },
  onShow: () {
    // Called when the toast becomes visible
  },
);

Parameters

ToastMeta

ToastMeta encapsulates all data for a toast notification:

ToastMeta(
  title: 'Custom Alert',
  description: 'Something happened.',
  icon: Icon(Icons.star, color: Colors.purple),
  color: Colors.purple.shade50,
  style: 'custom',
  duration: Duration(seconds: 5),
  position: ToastNotificationPosition.top,
  action: () => print("Tapped!"),
  dismiss: () => print("Dismiss pressed"),
  onDismiss: () => print("Toast dismissed"),
  onShow: () => print("Toast shown"),
  metaData: {"key": "value"},
)

Properties

copyWith

Create a modified copy of ToastMeta:

ToastMeta updated = originalMeta.copyWith(
  title: "New Title",
  duration: Duration(seconds: 10),
);

Positioning

Control where toasts appear on screen:

// Top of screen (default)
showToastNotification(context,
  id: "success",
  description: "Top alert",
  position: ToastNotificationPosition.top,
);

// Bottom of screen
showToastNotification(context,
  id: "info",
  description: "Bottom alert",
  position: ToastNotificationPosition.bottom,
);

// Center of screen
showToastNotification(context,
  id: "warning",
  description: "Center alert",
  position: ToastNotificationPosition.center,
);

Custom Toast Styles

Registering Styles

Register custom styles in your AppProvider:

class AppProvider implements NyProvider {
  @override
  setup(Nylo nylo) async {
    await nylo.configure(
      toastNotifications: {
        ...ToastNotificationConfig.styles,
        'custom': ToastNotification.style(
          icon: Icon(Icons.star, color: Colors.purple, size: 20),
          color: Colors.purple.shade50,
          defaultTitle: 'Custom!',
        ),
      },
    );
    return nylo;
  }
}

Or add styles at any time:

nylo.addToastNotifications({
  'promo': ToastNotification.style(
    icon: Icon(Icons.local_offer, color: Colors.pink, size: 20),
    color: Colors.pink.shade50,
    defaultTitle: 'Special Offer',
    position: ToastNotificationPosition.bottom,
    duration: Duration(seconds: 8),
  ),
});

Then use it:

showToastNotification(context, id: "promo", description: "50% off today!");

Creating a Style Factory

ToastNotification.style() creates a ToastStyleFactory:

static ToastStyleFactory style({
  required Widget icon,
  required Color color,
  required String defaultTitle,
  ToastNotificationPosition? position,
  Duration? duration,
  Widget Function(ToastMeta toastMeta)? builder,
})

Fully Custom Builder

For complete control over the toast widget:

'banner': (ToastMeta meta, void Function(ToastMeta) updateMeta) {
  return Container(
    margin: EdgeInsets.symmetric(horizontal: 16, vertical: 8),
    padding: EdgeInsets.all(16),
    decoration: BoxDecoration(
      color: Colors.indigo,
      borderRadius: BorderRadius.circular(12),
    ),
    child: Row(
      children: [
        Icon(Icons.campaign, color: Colors.white),
        SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisSize: MainAxisSize.min,
            children: [
              Text(meta.title, style: TextStyle(color: Colors.white, fontWeight: FontWeight.bold)),
              Text(meta.description, style: TextStyle(color: Colors.white70)),
            ],
          ),
        ),
      ],
    ),
  );
}

AlertTab

AlertTab is a badge widget for adding notification indicators to navigation tabs. It displays a badge that can be toggled and optionally persisted to storage.

AlertTab(
  state: "notifications_tab",
  alertEnabled: true,
  icon: Icon(Icons.notifications),
  alertColor: Colors.red,
)

Parameters

Factory Constructor

Create from a NavigationTab:

AlertTab.fromNavigationTab(
  myNavigationTab,
  index: 0,
  icon: Icon(Icons.home),
  stateName: "home_alert",
)

Examples

Success Alert After Save

void saveItem() async {
  try {
    await api<ItemApiService>((request) => request.saveItem(item));
    showToastSuccess(description: "Item saved successfully");
  } catch (e) {
    showToastDanger(description: "Could not save item. Please try again.");
  }
}

Interactive Toast with Action

showToastNotification(
  context,
  id: "info",
  title: "New Message",
  description: "You have a new message from Anthony",
  action: () {
    routeTo(ChatPage.path, data: {"userId": "123"});
  },
  duration: Duration(seconds: 8),
);

Bottom-Positioned Warning

showToastNotification(
  context,
  id: "warning",
  title: "No Internet",
  description: "You appear to be offline. Some features may not work.",
  position: ToastNotificationPosition.bottom,
  duration: Duration(seconds: 10),
);