Can sign out of the application

lib/helpers/account_credentials_helper.dart

@@ -10,7 +10,6 @@ import 'package:shared_preferences/shared_preferences.dart';
 /// @author Pierre HUBERT
 
 class AccountCredentialsHelper {
-
   /// Checkout whether current user is signed in or not
   Future<bool> signedIn() async {
     return await get() != null;
@@ -19,19 +18,18 @@ class AccountCredentialsHelper {
   /// Set new login tokens
   Future<void> set(LoginTokens tokens) async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
-    await prefs.setString("login_tokens", tokens.toString());
+    await prefs.setString(
+        "login_tokens", tokens == null ? "null" : tokens.toString());
   }
 
   /// Get current [LoginTokens]. Returns null if none or in case of failure
   Future<LoginTokens> get() async {
     try {
-
       SharedPreferences prefs = await SharedPreferences.getInstance();
       final string = prefs.getString("login_tokens");
-      if(string == null) return null;
+      if (string == null || string == "null") return null;
       return LoginTokens.fromJSON(jsonDecode(string));
-
+    } on Exception catch (e) {
-    } on Exception catch(e){
       print(e.toString());
       return null;
     }

lib/helpers/account_helper.dart

@@ -38,4 +38,10 @@ class AccountHelper {
 
     return AuthResult.SUCCESS;
   }
+
+  /// Sign out user
+  Future<void> signOut() async {
+    await AccountCredentialsHelper().set(null);
+  }
+
 }

lib/ui/routes/home_route.dart

@@ -1,3 +1,4 @@
+import 'package:comunic/ui/screens/menus_screen.dart';
 import 'package:comunic/ui/tiles/CustomBottomNavigationBarItem.dart';
 import 'package:flutter/material.dart';
 
@@ -50,7 +51,7 @@ class _HomeRouteState extends State<HomeRoute> {
         return Text("Conversations");
 
       case 1:
-        return Text("Menu");
+        return MenuScreen();
 
       default:
         throw "Invalid tab number : " + _currTab.toString();

lib/ui/screens/menus_screen.dart

@@ -0,0 +1,66 @@
+import 'package:comunic/helpers/account_helper.dart';
+import 'package:comunic/ui/routes/login_route.dart';
+import 'package:comunic/ui/tiles/menu_tile.dart';
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:flutter/material.dart';
+
+/// Menu screen
+///
+/// @author Pierre HUBERT
+
+class MenuScreen extends StatelessWidget {
+  /// Ask the user if he really wants to sign out from the application
+  Future<void> _confirmSignOut(BuildContext context) async  {
+    final result = await showDialog<bool>(
+      context: context,
+      builder: (c) {
+        return AlertDialog(
+          title: Text(tr("Confirm sign out")),
+          content: Text(
+              tr("Do your really want to sign out from the application ?")),
+          actions: <Widget>[
+            FlatButton(
+              child: Text(tr("Cancel").toUpperCase()),
+              onPressed: () {
+                Navigator.pop(context, false);
+              },
+            ),
+            FlatButton(
+              child: Text(
+                tr("Sign out").toUpperCase(),
+                style: TextStyle(color: Colors.red),
+              ),
+              onPressed: () {
+                Navigator.pop(context, true);
+              },
+            ),
+          ],
+        );
+      },
+    );
+
+    if(result == null || !result)
+      return;
+
+    await AccountHelper().signOut();
+
+    Navigator.pushReplacement(context, MaterialPageRoute(builder: (c){
+      return LoginRoute();
+    }));
+
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ListView(
+      children: <Widget>[
+        MenuTile(
+          title: tr("Sign out"),
+          onTap: () {
+            _confirmSignOut(context);
+          },
+        )
+      ],
+    );
+  }
+}

lib/ui/tiles/menu_tile.dart

@@ -0,0 +1,29 @@
+import 'package:flutter/material.dart';
+
+/// Menu tile
+///
+/// @author Pierre HUBERT
+
+class MenuTile extends StatelessWidget {
+  final String title;
+  final GestureTapCallback onTap;
+
+  const MenuTile({@required this.title, this.onTap}) : assert(title != null);
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: <Widget>[
+        Divider(),
+        InkWell(
+          onTap: onTap,
+          child: Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: Text(title),
+          ),
+        )
+      ],
+    );
+  }
+}