permission_handler.md

Permission Handler

The guide describes how to use work with permissions in Flutter.

permission_handler

permission_handler is a permissions plugin for
Flutter. This plugin provides a cross-platform (iOS, Android, Web, Windows) API to request and check
permissions.

Setup

Add permission_handler to your pubspec.yaml file.

Android:

In the AndroidManifest.xml file, add the permissions you need. For example, to request the camera permission, add the following line:

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

AndroidManifest example

IOS:

In the Info.plist file, add the permissions you need. For example, to request the camera permission, add the following line:

<key>NSCameraUsageDescription</key>
<string>camera</string>

Info.plist example In the Podfile file, you must describe the permissions you need:

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_ios_build_settings(target)
    # YOUR CUSTOM TARGET CODE HERE.
      target.build_configurations.each do |config|
        config.build_settings['ENABLE_BITCODE'] = 'NO'
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
          '$(inherited)',
            ## dart: PermissionGroup.camera
            'PERMISSION_CAMERA=1',
        ]
      end
  end
end

Usage

Create 'permissions' feature, using the masson.

In the 'permissions/domain/entities/failure' directory create the file 'permission_failure.dart':

/// Statuses of the user permission request error.  
sealed class PermissionFailure extends Failure {  
 PermissionFailure({required super.original, required super.trace});}  
  
/// Access denied.  
final class PermissionDenied extends PermissionFailure {  
 /// Create an instance of [PermissionDenied].
 PermissionDenied({required super.original, required super.trace});}  
  
/// Access denied forever.  
final class PermissionDeniedForever extends PermissionFailure {  
 /// Create an instance of [PermissionDeniedForever].
 PermissionDeniedForever({required super.original, required super.trace});}  
  
/// Service unavailable.  
final class ServiceDisabled extends PermissionFailure {  
 /// Create an instance of [ServiceDisabled].
 ServiceDisabled({required super.original, required super.trace});}  
  
/// Other errors when requesting user permissions.  
final class PermissionException extends PermissionFailure {  
 /// Create an instance of [PermissionException].
 PermissionException({required super.original, required super.trace});}  

In the permissions/domain/repositories directory create the file i_permission_handler_repository.dart:

/// Typedef for the result of a request for user permissions.  
typedef PermissionResult = Result<void, PermissionFailure>;  
  
/// Interface of the repository for obtaining permissions from the user.  
abstract class IPermissionHandlerRepository {  
  /// Check the permission for the use of [permission].
  Future<PermissionResult> checkPermission(Permission permission);
}  

In the permissions/data/repositories directory create the file permission_handler_repository.dart:

 /// Implementation of [PermissionHandlerRepository] for obtaining permissions from the user.
class PermissionHandlerRepository implements IPermissionHandlerRepository {
  /// Create an instance of [PermissionHandlerRepository]. 
  PermissionHandlerRepository();

  @override Future<PermissionResult> checkPermission(Permission permission) async {
    final status = await permission.status;
    if (status.isGranted) {
      return const Result.ok(null);
    }
    if (status.isDenied) {
      final status = await permission.request();
      if (status.isGranted) {
        return const Result.ok(null);
      } else {
        return Result.failed(PermissionDenied(original: null, trace: null));
      }
    }
    if (status.isPermanentlyDenied) {
      return Result.failed(PermissionDeniedForever(original: null, trace: null));
    }
    return Result.failed(PermissionException(original: null, trace: null));
  }
}  

Open the 'lib/features/app/di/app_scope' file.
Add the getter 'PermissionHandlerRepository' to the 'IAppScope' class:

 /// Permission handler repository.
 IPermissionHandlerRepository get permissionHandlerRepository;  

In the 'AppScope' class, add the 'PermissionHandlerRepository' variable:

...  
@override  
final IPermissionHandlerRepository permissionHandlerRepository;  
...  
AppScope({  
...  
  required this.permissionHandlerRepository,  
...  
});  

Open the 'lib/features/app/di/app_scope_register.dart' file. In the 'AppScopeRegister' class, create the 'PermissionHandlerRepository' instance:

 final permissionHandlerRepository = PermissionHandlerRepository();  

and pass it to the 'AppScope' constructor:

return AppScope(  
  ...  
  permissionHandlerRepository: permissionHandlerRepository,
  ...
);

Now you can get the permissions repository from the context.

 final permissionRepo = context.read<IAppScope>().permissionHandlerRepository;