diff --git a/converter_pro.iml b/converter_pro.iml
index e5c8371..0dd01cf 100644
--- a/converter_pro.iml
+++ b/converter_pro.iml
@@ -10,6 +10,7 @@
       <excludeFolder url="file://$MODULE_DIR$/.pub" />
       <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
+    <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="Dart SDK" level="project" />
     <orderEntry type="library" name="Flutter Plugins" level="project" />
diff --git a/lib/ConversionManager.dart b/lib/ConversionManager.dart
new file mode 100644
index 0000000..17bb44f
--- /dev/null
+++ b/lib/ConversionManager.dart
@@ -0,0 +1,93 @@
+import 'package:converter_pro/ConversionPage.dart';
+import 'package:converter_pro/Utils.dart';
+import 'package:flutter/material.dart';
+
+class ConversionManager extends StatefulWidget{
+  @override
+  _ConversionManager createState() => new _ConversionManager();
+
+}
+
+class _ConversionManager extends State<ConversionManager>{
+   static Node metro=Node(name: "Metro",
+      leafNodes: [
+        Node(isMultiplication: false, coefficient: 1000.0, name: "Millimetro",),
+        Node(isMultiplication: false, coefficient: 1000000.0, name: "Micrometro", ),
+        Node(isMultiplication: false, coefficient: 1000000000.0, name: "Nanometro",),
+        Node(isMultiplication: true, coefficient: 1000.0, name: "Chilometro",leafNodes: [
+          Node(isMultiplication: true, coefficient: 149597870.7, name: "Unità Astronomica",leafNodes: [
+            Node(isMultiplication: true, coefficient: 63241.1, name: "Anno Luce",),
+          ]),
+        ]),
+        Node(isMultiplication: false, coefficient: 100.0, name: "Centimetro", leafNodes: [
+          Node(isMultiplication: true, coefficient: 2.54, name: "Pollice", leafNodes: [
+            Node(isMultiplication: true, coefficient: 12.0, name: "Piede"),
+          ]),
+        ]),
+
+  ]
+  );
+
+
+  int currentPage=0;
+
+  @override
+  Widget build(BuildContext context) {
+
+    return Scaffold(
+      appBar: AppBar(title: new Text("Lunghezza"),),
+      drawer: new Drawer(child: ListView(
+        // Important: Remove any padding from the ListView.
+        padding: EdgeInsets.zero,
+        children: <Widget>[
+          DrawerHeader(
+            child: Text('Converter PRO'),
+            decoration: BoxDecoration(
+              color: Colors.red,
+            ),
+          ),
+          ListTile(
+            title: Text("Lunghezza"),
+            selected: true,
+            onTap: () {
+              if(currentPage!=0) {
+                setState((){
+                  currentPage=0;
+                });
+              }
+            },
+          ),
+          ListTile(
+            title: Text("Superficie"),
+            onTap: () {
+              // Update the state of the app
+              // ...
+            },
+          ),
+          ListTile(
+            title: Text("Volume"),
+            onTap: () {
+              // Update the state of the app
+              // ...
+            },
+          ),
+          ListTile(
+            title: Text("Tempo"),
+            onTap: () {
+              // Update the state of the app
+              // ...
+            },
+          ),
+          ListTile(
+            title: Text("Temperatura"),
+            onTap: () {
+              // Update the state of the app
+              // ...
+            },
+          ),
+        ],
+      ),),
+      body: currentPage==0 ? ConversionPage(metro) : ConversionPage(metro)
+    );
+  }
+}
diff --git a/lib/ConversionPage.dart b/lib/ConversionPage.dart
index 8004286..4c14884 100644
--- a/lib/ConversionPage.dart
+++ b/lib/ConversionPage.dart
@@ -2,8 +2,7 @@ import 'package:converter_pro/Utils.dart';
 import 'package:flutter/material.dart';
 import 'package:fluttertoast/fluttertoast.dart';
 
-class ConversionPage extends StatefulWidget{
-
+class ConversionPage extends StatefulWidget {
   ConversionPage(this.fatherNode);
 
   Node fatherNode;
@@ -12,34 +11,32 @@ class ConversionPage extends StatefulWidget{
   _ConversionPage createState() => new _ConversionPage(fatherNode);
 }
 
-class _ConversionPage extends State<ConversionPage>{
-
+class _ConversionPage extends State<ConversionPage> {
   Node fatherNode;
   List<Node> listaNodi;
-  List<TextEditingController> listaController=new List();
-  List<FocusNode> listaFocus=new List();
+  List<TextEditingController> listaController = new List();
+  List<FocusNode> listaFocus = new List();
   Node selectedNode;
 
-  _ConversionPage(Node fatherNode){
-    this.fatherNode=fatherNode;
-    listaNodi=fatherNode.getNodiFiglio();
-
+  _ConversionPage(Node fatherNode) {
+    this.fatherNode = fatherNode;
+    listaNodi = fatherNode.getNodiFiglio();
   }
 
   @override
   void initState() {
     super.initState();
-    for(Node node in listaNodi){
+    for (Node node in listaNodi) {
       listaController.add(new TextEditingController());
-      FocusNode focus=new FocusNode();
-      focus.addListener((){
+      FocusNode focus = new FocusNode();
+      focus.addListener(() {
         if (focus.hasFocus) {
-          if(selectedNode!=null) {
+          if (selectedNode != null) {
             selectedNode.selectedNode = false;
           }
-          node.selectedNode=true;
-          node.convertedNode=true;
-          selectedNode=node;
+          node.selectedNode = true;
+          node.convertedNode = true;
+          selectedNode = node;
         }
       });
       listaFocus.add(focus);
@@ -50,60 +47,54 @@ class _ConversionPage extends State<ConversionPage>{
   void dispose() {
     FocusNode focus;
     TextEditingController TEC;
-    for(int i=0;i<listaFocus.length;i++){
-      focus=listaFocus[i];
-      focus.removeListener((){});
+    for (int i = 0; i < listaFocus.length; i++) {
+      focus = listaFocus[i];
+      focus.removeListener(() {});
       focus.dispose();
-      TEC=listaController[i];
+      TEC = listaController[i];
       TEC.dispose();
     }
     super.dispose();
   }
 
-  List<UnitCard> _createList(){
-    List<UnitCard> listaCard=new List();
-    for (int i=0; i<listaNodi.length;i++){
-      Node nodo=listaNodi[i];
+  List<UnitCard> _createList() {
+    List<UnitCard> listaCard = new List();
+    for (int i = 0; i < listaNodi.length; i++) {
+      Node nodo = listaNodi[i];
       TextEditingController controller;
-      controller=listaController[i];
+      controller = listaController[i];
 
-      if(nodo.value!=null && !nodo.selectedNode)
+      if (nodo.value != null && !nodo.selectedNode)
         controller.text = nodo.value.toString();
-      else if(nodo.value==null && !nodo.selectedNode)
-        controller.text = "";
+      else if (nodo.value == null && !nodo.selectedNode) controller.text = "";
 
       listaCard.add(new UnitCard(
           node: nodo,
           textField: TextField(
-            style: TextStyle(fontSize: 16.0,color: Colors.black,),
-            keyboardType: TextInputType.numberWithOptions(decimal: true,signed: false),
+            style: TextStyle(
+              fontSize: 16.0,
+              color: Colors.black,
+            ),
+            keyboardType:
+                TextInputType.numberWithOptions(decimal: true, signed: false),
             controller: controller,
             focusNode: listaFocus[i],
-            onChanged: (String txt){
+            onChanged: (String txt) {
               nodo.value = txt == "" ? null : double.parse(txt);
               setState(() {
                 fatherNode.ResetConvertedNode();
                 fatherNode.Convert();
               });
             },
-          )
-      ));
-
+          )));
     }
     return listaCard;
   }
 
-
   @override
   Widget build(BuildContext context) {
-    List<UnitCard> listCard=_createList();
+    List<UnitCard> listCard = _createList();
 
-    return Scaffold(
-      appBar: AppBar(title: new Text("Lunghezza"),),
-      body: ListView(
-        padding: new EdgeInsets.all(10.0),
-        children: listCard
-      ),
-    );
+    return ListView(padding: new EdgeInsets.all(10.0), children: listCard);
   }
 }
diff --git a/lib/Utils.dart b/lib/Utils.dart
index f898bfe..7dd0adf 100644
--- a/lib/Utils.dart
+++ b/lib/Utils.dart
@@ -63,11 +63,11 @@ class Node {
               : (node.isMultiplication ? node.value * node.coefficient : node.value / node.coefficient); //metto in questo nodo il valore convertito
           convertedNode = true;
           _ApplyDown(); //converto i nodi sottostanti
-        } else { //se non c'è valore
-          if (node.leafNodes != null) { //Però ha almeno un nodo foglia
+        }
+        else if (node.leafNodes != null) { //Però ha almeno un nodo foglia
             node.Convert(); //ripeti la procedura
-            Convert();
-          }
+            if(node.convertedNode)
+              Convert();
         }
       }
     }
diff --git a/lib/main.dart b/lib/main.dart
index f0e64e7..428fab8 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -1,22 +1,15 @@
-import 'package:converter_pro/ConversionPage.dart';
-import 'package:converter_pro/Utils.dart';
+import 'package:converter_pro/ConversionManager.dart';
 import 'package:flutter/material.dart';
 
 void main() => runApp(new App());
 
 class App extends StatelessWidget {
-  static Node foot=Node(isMultiplication: true, coefficient: 12.0, name: "foot", selectedNode: false, convertedNode: false);
-  static Node inch=Node(isMultiplication: true, coefficient: 2.54, name: "inch", leafNodes: [foot], selectedNode: false, convertedNode: false);
-  static Node millimetro=Node(isMultiplication: false, coefficient: 10.0, name: "millimetro", selectedNode: false, convertedNode: false);
-  static Node centimetro=Node(isMultiplication: false, coefficient: 100.0, name: "centimetro", leafNodes: [millimetro,inch], selectedNode: false, convertedNode: false);
-  static Node metro=Node(name: "metro", leafNodes: [centimetro], selectedNode: false, convertedNode: false);
-
 
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'FCM - Calculator',
-      home: ConversionPage(metro),
+      home: ConversionManager(),
       theme: ThemeData(
         primaryColor: Colors.red,
         accentColor: Colors.indigo,