skills/flutter/references/features-pop-scope.md

name	description
features-pop-scope	Flutter PopScope - handle back button and navigation pop events

PopScope

PopScope (formerly WillPopScope) handles back button and navigation pop events.

Basic Usage

PopScope(
  canPop: false, // Prevent popping
  onPopInvoked: (didPop) {
    if (!didPop) {
      // Handle back button press
      showDialog(...);
    }
  },
  child: Scaffold(...),
)

Prevent Pop

PopScope(
  canPop: false,
  onPopInvoked: (didPop) {
    if (!didPop) {
      // Show confirmation dialog
      showDialog(
        context: context,
        builder: (context) => AlertDialog(
          title: Text('Exit?'),
          content: Text('Are you sure?'),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: Text('Cancel'),
            ),
            ElevatedButton(
              onPressed: () {
                Navigator.pop(context);
                Navigator.pop(context); // Pop this route
              },
              child: Text('Exit'),
            ),
          ],
        ),
      );
    }
  },
  child: Scaffold(...),
)

Conditional Pop

PopScope(
  canPop: _isFormDirty ? false : true,
  onPopInvoked: (didPop) {
    if (!didPop && _isFormDirty) {
      // Show unsaved changes dialog
      showDialog(...);
    }
  },
  child: Form(...),
)

Save on Pop

PopScope(
  canPop: false,
  onPopInvoked: (didPop) async {
    if (!didPop) {
      // Save data before popping
      await saveData();
      if (mounted) {
        Navigator.pop(context);
      }
    }
  },
  child: Scaffold(...),
)

Key Points

• Use PopScope to handle back button
• Set canPop: false to prevent automatic pop
• Use onPopInvoked to handle pop events
• Check didPop to see if pop occurred
• Use for unsaved changes warnings
• Use for confirmation dialogs
• Save data before popping if needed
• Replaced WillPopScope in newer Flutter versions