privacy_screen 0.0.6

A plugin for hiding sensitive data when app is in app switcher and in background. It also provides automatic lock triggers with native lifeCycle events, and native lifeCycle listeners.

privacy_screen

Flutter plugin to provide a privacy screen feature (hide content when app is in background)

Pluggin in iOS is in swift

Pluggin in Android is in Kotlin

This plugin used native app lifeCycles instead of flutter's to ensure it works when flutter entered a native view (eg: from a native plugin)

This plugin also provides a native life cycle listener through instance.appLifeCycleEvents stream

Features

IOS	Android	Feature
✔️	❌	Custom privacy screen image
❌	Mandatory when enabled	Disable screenshot
✔️	✔️	Auto lock trigger with native lifecycle
✔️	✔️	Native lifecycle listener

Cons

• IOS

  • The lock can not be presented when app is currently showing a native view (eg: from a native plugin like urlLauncher), due to Flutter's view (The lock widget) can not go on top of the native view controller. However, the privacy view will always work (because it's native)

• Android

  • FLAG_SECURE currently only on flutter window so it won't work in a native view until back to flutter window.
  • Can not customize privacy view. FLAG_SECURE will disable screenshot and show a black/white screen when app entered background. If you want to enable screen shot and still use privacy view, there's no way on android to do as far as I know.

IOS

Android

Usage

Installation

Add privacy_screen as a dependency in your pubspec.yaml file.

Import

import 'package:privacy_screen/privacy_screen.dart';

And then you can simply call functions of PrivacyScreen class instance anywhere

To enable privacy view

bool result = await PrivacyScreen.instance.enable(
    iosOptions: const PrivacyIosOptions(
        enablePrivacy: true,
        privacyImageName: "LaunchImage",
        autoLockAfterSeconds: 5,
        lockTrigger: IosLockTrigger.didEnterBackground,
    ),
    androidOptions: const PrivacyAndroidOptions(
        enableSecure: true,
        autoLockAfterSeconds: 5,
    ),
    backgroundColor: Colors.white.withOpacity(0),
    blurEffect: PrivacyBlurEffect.extraLight,
);

To disable privacy view

bool result = await PrivacyScreen.instance.disable();

To use custom image on IOS

Supply privacyImageName in iosOptions

Open your project's ios folder with XCode and add the image asset in the runner/assets

The privacyImageName String must match the asset name, eg: "LaunchImage"

To use the lock feature

Put PrivacyGate widget at your root and provide your own lockBuilder widget.

Option 1

Use it at MaterialApp's builder and provide a navigatorKey.

By providing navigatorKey, the plugin will put your lockBuilder into a new Route, and you can write WillPopScope in your lockBuilder to prevent navigation once entered the lock screen.

// Your MaterialApp
class MyApp extends StatelessWidget {
  MyApp({Key? key}) : super(key: key);
  // Give it a key to use route
  final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // Give it a key
      navigatorKey: navigatorKey,
      builder: (_, child) {
        return PrivacyGate(
          lockBuilder: (ctx) => const LockerPage(),
          // Give it a key
          navigatorKey: navigatorKey,
          onLifeCycleChanged: (value) => print(value),
          onLock: () => print("onLock"),
          onUnlock: () => print("onUnlock"),
          child: child,
        );
      },
      home: const FirstRoute(),
    );
  }
}

// Your LockerPage
class LockerPage extends StatelessWidget {
  const LockerPage({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: () async {
        var result = await showDialog(
          context: context,
          builder: (ctx) => Dialog(
            child: Padding(
              padding: const EdgeInsets.all(16.0),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const Text(
                    "Confirmation",
                    style: TextStyle(fontSize: 24),
                  ),
                  const Text("Are you sure to unlock?"),
                  Row(
                    children: [
                      Expanded(
                        child: ElevatedButton(
                          onPressed: () {
                            Navigator.of(context).pop(true);
                          },
                          child: const Text('Yes'),
                        ),
                      ),
                      const SizedBox(width: 8.0),
                      Expanded(
                        child: ElevatedButton(
                          onPressed: () {
                            Navigator.of(context).pop(false);
                          },
                          child: const Text('No'),
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ),
        );
        if (result == true) {
          PrivacyScreen.instance.unlock();
        }
        return false;
      },
      child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              TextFormField(),
              ElevatedButton(
                child: const Text("Unlock"),
                onPressed: () => PrivacyScreen.instance.unlock(),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

Option 2

Without providing navigatorKey, the plugin will put your lock in Stack with your app. This method can not handle hardware back button thus even the lock is showing, user can still navigate away by pressing the hardware back button on android.

Option 3

Without providing lockBuilder, you can use onLock and onUnlock event trigger to write you own lock mechanisms, just make sure you use instance.unlock to reset the locker properly.

Manual Lock

PrivacyScreen.instance.lock();

Unlock

PrivacyScreen.instance.unlock();

Pause auto lock

This will pause the auto lock until resume.

It's is usefull when you set lockTrigger as IosLockTrigger.willResignActive because actions like swipe down to show system menu and authenticate with faceID will also trigger the willResignActive action (you don't want to lock it right after faceID unlock.. maybe? so you can pause before faceID and resume after faceID done)

PrivacyScreen.instance.pauseLock();

Resume auto lock

PrivacyScreen.instance.resumeLock();

Parameters

When calling instance.enable(), configurations can be provided:

Shared options

param	feature
backgroundColor	Background color of the privacy view on IOS, and of the locker on both platforms
blurEffect	The blurEffect used according to IOS's blurEffect.

IOS options

param	feature
enablePrivacy	Enable the privacy view when app goes into background
autoLockAfterSeconds	Trigger lock when coming back (x) seconds after enter background. This is seperated from enablePriacy, so you can disable privacy and still use auto lock
privacyImageName	The name of the native IOS runner asset you want to show on the privacy view. Leave empty if you don't want to show an image
lockTrigger	What native event should trigger the lock mechanism. Try avoid using IosLockTrigger.willResignActive

Android options

param	feature
enableSecure	Add FLAG_SECURE to android (Hide content and disable screenshot)
autoLockAfterSeconds	Trigger lock when coming back (x) seconds after enter background. This is seperated from enableSecure, so you can disable FLAG_SECURE and still use auto lock

Full Example (Because you all want to see in Readme)

import 'package:flutter/material.dart';
import 'package:privacy_screen/privacy_screen.dart';
import 'package:url_launcher/url_launcher.dart';

void main() async {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  MyApp({Key? key}) : super(key: key);
  final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      navigatorKey: navigatorKey,
      builder: (_, child) {
        return PrivacyGate(
          lockBuilder: (ctx) => const LockerPage(),
          navigatorKey: navigatorKey,
          onLifeCycleChanged: (value) => print(value),
          onLock: () => print("onLock"),
          onUnlock: () => print("onUnlock"),
          child: child,
        );
      },
      home: const FirstRoute(),
    );
  }
}

class FirstRoute extends StatefulWidget {
  const FirstRoute({Key? key}) : super(key: key);

  @override
  State<FirstRoute> createState() => _FirstRouteState();
}

class _FirstRouteState extends State<FirstRoute> {
  List<String> lifeCycleHistory = [];

  @override
  void dispose() {
    super.dispose();
  }

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Plugin example app'),
      ),
      body: SingleChildScrollView(
        child: SizedBox(
          width: double.infinity,
          child: SafeArea(
            child: Padding(
              padding: const EdgeInsets.all(16.0),
              child: Column(
                children: [
                  ElevatedButton(
                    onPressed: () =>
                        launchUrl(Uri.parse("https://www.flutter.dev/")),
                    child: const Text("Test Native: Url Launch"),
                  ),
                  const Divider(),
                  ElevatedButton(
                    onPressed: () async {
                      await PrivacyScreen.instance.enable(
                        iosOptions: const PrivacyIosOptions(
                          enablePrivacy: true,
                          privacyImageName: "LaunchImage",
                          autoLockAfterSeconds: 5,
                          lockTrigger: IosLockTrigger.didEnterBackground,
                        ),
                        androidOptions: const PrivacyAndroidOptions(
                          enableSecure: true,
                          autoLockAfterSeconds: 5,
                        ),
                        backgroundColor: Colors.white.withOpacity(0),
                        blurEffect: PrivacyBlurEffect.extraLight,
                      );
                    },
                    child: const Text("Enable extraLight"),
                  ),
                  ElevatedButton(
                    onPressed: () async {
                      await PrivacyScreen.instance.enable(
                        iosOptions: const PrivacyIosOptions(
                          enablePrivacy: true,
                          privacyImageName: "LaunchImage",
                          autoLockAfterSeconds: 5,
                          lockTrigger: IosLockTrigger.didEnterBackground,
                        ),
                        androidOptions: const PrivacyAndroidOptions(
                          enableSecure: true,
                          autoLockAfterSeconds: 5,
                        ),
                        backgroundColor: Colors.white.withOpacity(0),
                        blurEffect: PrivacyBlurEffect.light,
                      );
                    },
                    child: const Text("Enable light"),
                  ),
                  ElevatedButton(
                    onPressed: () async {
                      await PrivacyScreen.instance.enable(
                        iosOptions: const PrivacyIosOptions(
                          enablePrivacy: true,
                          privacyImageName: "LaunchImage",
                          autoLockAfterSeconds: 5,
                          lockTrigger: IosLockTrigger.didEnterBackground,
                        ),
                        androidOptions: const PrivacyAndroidOptions(
                          enableSecure: true,
                          autoLockAfterSeconds: 5,
                        ),
                        backgroundColor: Colors.red.withOpacity(0.4),
                        blurEffect: PrivacyBlurEffect.dark,
                      );
                    },
                    child: const Text("Enable dark"),
                  ),
                  ElevatedButton(
                    onPressed: () async {
                      await PrivacyScreen.instance.disable();
                    },
                    child: const Text("Disable"),
                  ),
                  const Divider(),
                  ElevatedButton(
                    onPressed: () {
                      PrivacyScreen.instance.lock();
                    },
                    child: const Text("Lock"),
                  ),
                  ElevatedButton(
                    onPressed: () {
                      PrivacyScreen.instance.pauseLock();
                    },
                    child: const Text("Pause Auto Lock"),
                  ),
                  ElevatedButton(
                    onPressed: () {
                      PrivacyScreen.instance.pauseLock();
                    },
                    child: const Text("Resume Auto Lock"),
                  ),
                  const Divider(),
                  ...lifeCycleHistory.map((e) => Text(e)).toList(),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class LockerPage extends StatelessWidget {
  const LockerPage({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: () async {
        var result = await showDialog(
          context: context,
          builder: (ctx) => Dialog(
            child: Padding(
              padding: const EdgeInsets.all(16.0),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const Text(
                    "Confirmation",
                    style: TextStyle(fontSize: 24),
                  ),
                  const Text("Are you sure to unlock?"),
                  Row(
                    children: [
                      Expanded(
                        child: ElevatedButton(
                          onPressed: () {
                            Navigator.of(context).pop(true);
                          },
                          child: const Text('Yes'),
                        ),
                      ),
                      const SizedBox(width: 8.0),
                      Expanded(
                        child: ElevatedButton(
                          onPressed: () {
                            Navigator.of(context).pop(false);
                          },
                          child: const Text('No'),
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ),
        );
        if (result == true) {
          PrivacyScreen.instance.unlock();
        }
        return false;
      },
      child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              TextFormField(),
              ElevatedButton(
                child: const Text("Unlock"),
                onPressed: () => PrivacyScreen.instance.unlock(),
              ),
            ],
          ),
        ),
      ),
    );
  }
}