permission_handler in Flutter: solved exercise with full permissions flow

Requesting permissions correctly is one of the leading sources of poor user experience in mobile apps. permission_handler provides a unified API to request and check permissions on Android and iOS, handle the permanentlyDenied state, and open system settings.

Problem statement

Implement a permissions flow that:

Checks camera, microphone, and location permission status before requesting.
Shows the user context before the system dialog.
Handles all four states: granted, denied, permanentlyDenied, restricted.
Redirects to system settings when a permission is permanently denied.
Requests multiple permissions at once.

Dependencies

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dependencies:
  permission_handler: ^11.3.1

Android setup

In android/app/src/main/AndroidManifest.xml:

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<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

iOS setup

In ios/Runner/Info.plist:

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<key>NSCameraUsageDescription</key>
<string>We need camera access to scan documents</string>
<key>NSMicrophoneUsageDescription</key>
<string>We need the microphone to record voice notes</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>We use your location to show nearby stores</string>

Full solution

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

void main() => runApp(const MaterialApp(home: PermissionsDemo()));

// ── Permission definitions with metadata ───────────────────────────────────────
class PermissionItem {
  final Permission permission;
  final String name;
  final IconData icon;
  final String rationale;

  const PermissionItem({
    required this.permission,
    required this.name,
    required this.icon,
    required this.rationale,
  });
}

const _permissions = [
  PermissionItem(
    permission: Permission.camera,
    name: 'Camera',
    icon: Icons.camera_alt,
    rationale: 'We need camera access to scan documents and QR codes.',
  ),
  PermissionItem(
    permission: Permission.microphone,
    name: 'Microphone',
    icon: Icons.mic,
    rationale: 'We use the microphone to record voice notes.',
  ),
  PermissionItem(
    permission: Permission.locationWhenInUse,
    name: 'Location',
    icon: Icons.location_on,
    rationale: 'Your location lets us show you nearby stores.',
  ),
];

// ── Main screen ────────────────────────────────────────────────────────────────
class PermissionsDemo extends StatefulWidget {
  const PermissionsDemo({super.key});
  @override
  State<PermissionsDemo> createState() => _PermissionsDemoState();
}

class _PermissionsDemoState extends State<PermissionsDemo>
    with WidgetsBindingObserver {
  final _statuses = <Permission, PermissionStatus>{};
  bool _loading = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _checkAll();
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  // Refresh statuses when returning from system Settings
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.resumed) _checkAll();
  }

  Future<void> _checkAll() async {
    setState(() => _loading = true);
    final results = await Future.wait(
      _permissions.map((p) => p.permission.status),
    );
    setState(() {
      for (var i = 0; i < _permissions.length; i++) {
        _statuses[_permissions[i].permission] = results[i];
      }
      _loading = false;
    });
  }

  Future<void> _requestPermission(PermissionItem item) async {
    final current = _statuses[item.permission];

    if (current == PermissionStatus.permanentlyDenied) {
      _showPermanentlyDeniedDialog(item);
      return;
    }

    if (current != PermissionStatus.granted) {
      final proceed = await _showRationaleDialog(item);
      if (!proceed) return;
    }

    final status = await item.permission.request();
    setState(() => _statuses[item.permission] = status);

    if (status == PermissionStatus.permanentlyDenied && mounted) {
      _showPermanentlyDeniedDialog(item);
    }
  }

  Future<void> _requestAll() async {
    final notGranted = _permissions
        .where((p) => _statuses[p.permission] != PermissionStatus.granted)
        .toList();

    if (notGranted.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('All permissions already granted ✅')),
      );
      return;
    }

    final results = await [
      for (final p in notGranted) p.permission
    ].request();

    setState(() {
      for (final entry in results.entries) {
        _statuses[entry.key] = entry.value;
      }
    });

    final denied = results.entries
        .where((e) => e.value == PermissionStatus.permanentlyDenied)
        .toList();
    if (denied.isNotEmpty && mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
              '${denied.length} permission(s) permanently denied. '
              'Go to Settings to enable them.'),
          action: SnackBarAction(label: 'Settings', onPressed: openAppSettings),
        ),
      );
    }
  }

  Future<bool> _showRationaleDialog(PermissionItem item) async {
    return await showDialog<bool>(
          context: context,
          builder: (ctx) => AlertDialog(
            title: Row(
              children: [
                Icon(item.icon),
                const SizedBox(width: 8),
                Text('Permission: ${item.name}'),
              ],
            ),
            content: Text(item.rationale),
            actions: [
              TextButton(
                onPressed: () => Navigator.pop(ctx, false),
                child: const Text('Not now'),
              ),
              FilledButton(
                onPressed: () => Navigator.pop(ctx, true),
                child: const Text('Continue'),
              ),
            ],
          ),
        ) ??
        false;
  }

  void _showPermanentlyDeniedDialog(PermissionItem item) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Permission permanently denied'),
        content: Text(
          'The "${item.name}" permission was permanently denied. '
          'To enable it, go to Settings > Apps > ${item.name}.',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () {
              Navigator.pop(ctx);
              openAppSettings();
            },
            child: const Text('Open Settings'),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Permissions with permission_handler'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            tooltip: 'Check statuses',
            onPressed: _checkAll,
          ),
        ],
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  ...List.generate(_permissions.length, (i) {
                    final item = _permissions[i];
                    final status = _statuses[item.permission];
                    return Card(
                      margin: const EdgeInsets.only(bottom: 8),
                      child: ListTile(
                        leading: Icon(item.icon, color: _statusColor(status)),
                        title: Text(item.name),
                        subtitle: Text(_statusLabel(status)),
                        trailing: _StatusChip(status: status),
                        onTap: () => _requestPermission(item),
                      ),
                    );
                  }),
                  const SizedBox(height: 8),
                  FilledButton.icon(
                    onPressed: _requestAll,
                    icon: const Icon(Icons.shield),
                    label: const Text('Request all permissions'),
                  ),
                  const SizedBox(height: 8),
                  OutlinedButton.icon(
                    onPressed: openAppSettings,
                    icon: const Icon(Icons.settings),
                    label: const Text('Open system settings'),
                  ),
                  const Spacer(),
                  const _Legend(),
                ],
              ),
            ),
    );
  }

  Color _statusColor(PermissionStatus? s) {
    switch (s) {
      case PermissionStatus.granted: return Colors.green;
      case PermissionStatus.denied: return Colors.orange;
      case PermissionStatus.permanentlyDenied: return Colors.red;
      default: return Colors.grey;
    }
  }

  String _statusLabel(PermissionStatus? s) {
    switch (s) {
      case PermissionStatus.granted: return 'Granted — tap to revoke in Settings';
      case PermissionStatus.denied: return 'Denied — tap to request';
      case PermissionStatus.permanentlyDenied: return 'Permanently denied — tap to open Settings';
      case PermissionStatus.restricted: return 'Restricted by device policy';
      case PermissionStatus.limited: return 'Limited access (iOS)';
      default: return 'Unknown status';
    }
  }
}

class _StatusChip extends StatelessWidget {
  final PermissionStatus? status;
  const _StatusChip({this.status});

  @override
  Widget build(BuildContext context) {
    final (label, color) = switch (status) {
      PermissionStatus.granted => ('✅ OK', Colors.green),
      PermissionStatus.denied => ('⚠️ Denied', Colors.orange),
      PermissionStatus.permanentlyDenied => ('🚫 Perm.', Colors.red),
      PermissionStatus.restricted => ('🔒 Restr.', Colors.grey),
      _ => ('❓', Colors.grey),
    };
    return Chip(
      label: Text(label, style: const TextStyle(fontSize: 11)),
      backgroundColor: color.withOpacity(0.1),
      side: BorderSide(color: color.withOpacity(0.3)),
      padding: EdgeInsets.zero,
      visualDensity: VisualDensity.compact,
    );
  }
}

class _Legend extends StatelessWidget {
  const _Legend();
  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Permission statuses:', style: Theme.of(context).textTheme.labelMedium),
        const SizedBox(height: 4),
        const Text('✅ granted — access granted', style: TextStyle(fontSize: 12)),
        const Text('⚠️ denied — denied (can ask again)', style: TextStyle(fontSize: 12)),
        const Text('🚫 permanentlyDenied — only via Settings', style: TextStyle(fontSize: 12)),
        const Text('🔒 restricted — blocked by MDM/parental controls', style: TextStyle(fontSize: 12)),
      ],
    );
  }
}

Recommended permissions flow

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check() → granted? → use feature
        → denied? → show rationale → request() → granted/denied/permanentlyDenied
        → permanentlyDenied? → openAppSettings()
        → restricted? → show explanatory message

Common mistakes

Not declaring the permission in AndroidManifest or Info.plist: the plugin returns denied even though the user never saw a dialog. Always check the native config files first.
Not refreshing status when returning from Settings: when the user enables a permission in system Settings and returns to the app, the status is not updated automatically. Use WidgetsBindingObserver.didChangeAppLifecycleState to refresh.
Showing the system dialog without prior context: Apple and Google may reject your app if you request permissions without first explaining why you need them. Always show a rationale before the native dialog.

Practical use

Any app using camera, location, microphone, notifications, contacts, or Bluetooth needs this flow. It is especially critical in health and fintech apps where permissions are auditable.

Recommended next exercise

Guided practice and next step

FAQ

Can I request permissions before the user reaches the screen that needs them?

Not recommended. Request permissions just before the action that requires them, with a clear rationale. Requesting them at app launch drastically reduces grant rates.

Does `permission_handler` work on Web and Desktop?

It has limited support. On Web some permissions are managed by the browser. On Desktop (Windows/macOS/Linux) support varies by platform and permission.

What is the difference between `denied` and `permanentlyDenied`?

denied means the user rejected the dialog but can be asked again. permanentlyDenied (Android: “Don’t ask again”) means the system will no longer show the dialog — only openAppSettings() can resolve it.

permission_handler in Flutter: solved exercise with full permissions flow