Refactor "drawer"

- Reduce number of items
- Long-pressing the "back" button opens the drawer

Ref: https://stackoverflow.com/questions/58095547/flutter-scaffold-ofcontext-opendrawer-doesnt-work

lib/widget/back.dart

@@ -7,13 +7,15 @@
 import "package:flutter/cupertino.dart";
 import "package:flutter/material.dart";
 
-Widget backButton(BuildContext context) {
+import "package:inventree/widget/drawer.dart";
+
+Widget backButton(BuildContext context, GlobalKey<ScaffoldState> key) {
 
   return GestureDetector(
     onLongPress: () {
-      while (Navigator.of(context).canPop()) {
+      // Display the menu
-        Navigator.of(context).pop();
+      key.currentState!.openDrawer();
-      }
+      print("hello?");
     },
     child: IconButton(
       icon: BackButtonIcon(),

lib/widget/drawer.dart

@@ -28,7 +28,9 @@ class InvenTreeDrawer extends StatelessWidget {
   void _home() {
     _closeDrawer();
 
-    Navigator.pushNamedAndRemoveUntil(context, "/", (r) => false);
+    while (Navigator.of(context).canPop()) {
+      Navigator.of(context).pop();
+    }
   }
 
   void _search() {
@@ -37,12 +39,7 @@ class InvenTreeDrawer extends StatelessWidget {
 
     _closeDrawer();
 
-    showSearch(
+    // TODO: Open search dialog
-      context: context,
-      delegate: PartSearchDelegate(context)
-    );
-
-    //Navigator.push(context, MaterialPageRoute(builder: (context) => SearchWidget()));
   }
 
   /*
@@ -56,48 +53,6 @@ class InvenTreeDrawer extends StatelessWidget {
     scanQrCode(context);
   }
 
-  /*
-   * Display the top-level PartCategory list
-   */
-  void _showParts() {
-    if (!InvenTreeAPI().checkConnection(context)) return;
-
-    _closeDrawer();
-    Navigator.push(context, MaterialPageRoute(builder: (context) => CategoryDisplayWidget(null)));
-  }
-
-  /*
-   * Display the top-level StockLocation list
-   */
-  void _showStock() {
-    if (!InvenTreeAPI().checkConnection(context)) return;
-    _closeDrawer();
-    Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(null)));
-  }
-
-  /*
-  void _showSuppliers() {
-    if (!InvenTreeAPI().checkConnection(context)) return;
-    _closeDrawer();
-
-    Navigator.push(context, MaterialPageRoute(builder: (context) => CompanyListWidget(L10().suppliers, {"is_supplier": "true"})));
-  }
-
-  void _showManufacturers() {
-    if (!InvenTreeAPI().checkConnection(context)) return;
-    _closeDrawer();
-
-    Navigator.push(context, MaterialPageRoute(builder: (context) => CompanyListWidget(L10().manufacturers, {"is_manufacturer": "true"})));
-  }
-
-  void _showCustomers() {
-    if (!InvenTreeAPI().checkConnection(context)) return;
-    _closeDrawer();
-
-    Navigator.push(context, MaterialPageRoute(builder: (context) => CompanyListWidget(L10().customers, {"is_customer": "true"})));
-  }
-   */
-
   /*
    * Load settings widget
    */
@@ -114,11 +69,7 @@ class InvenTreeDrawer extends StatelessWidget {
               context: context,
               tiles: <Widget>[
                 ListTile(
-                  leading: Image.asset(
+                  leading: FaIcon(FontAwesomeIcons.home),
-                    "assets/image/icon.png",
-                    fit: BoxFit.scaleDown,
-                    width: 30,
-                  ),
                   title: Text(
                     L10().appTitle,
                     style: TextStyle(fontWeight: FontWeight.bold),
@@ -135,35 +86,6 @@ class InvenTreeDrawer extends StatelessWidget {
                   leading: FaIcon(FontAwesomeIcons.search),
                   onTap: _search,
                 ),
-                ListTile(
-                  title: Text(L10().parts),
-                  leading: Icon(Icons.category),
-                  onTap: _showParts,
-                ),
-                ListTile(
-                  title: Text(L10().stock),
-                  leading: FaIcon(FontAwesomeIcons.boxes),
-                  onTap: _showStock,
-                ),
-
-                /*
-                ListTile(
-                  title: Text("Suppliers"),
-                  leading: FaIcon(FontAwesomeIcons.building),
-                  onTap: _showSuppliers,
-                ),
-                ListTile(
-                  title: Text("Manufacturers"),
-                  leading: FaIcon(FontAwesomeIcons.industry),
-                    onTap: _showManufacturers,
-                ),
-                ListTile(
-                  title: Text("Customers"),
-                  leading: FaIcon(FontAwesomeIcons.users),
-                  onTap: _showCustomers,
-                ),
-                */
-
                 ListTile(
                   title: Text(L10().settings),
                   leading: Icon(Icons.settings),

lib/widget/refreshable_state.dart

@@ -62,15 +62,6 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
     });
   }
 
-  // Function to construct an appbar (override if needed)
-  AppBar getAppBar(BuildContext context) {
-    return AppBar(
-      title: Text(getAppBarTitle(context)),
-      actions: getAppBarActions(context),
-      leading: backButton(context),
-    );
-  }
-
   // Function to construct a drawer (override if needed)
   Widget getDrawer(BuildContext context) {
     return InvenTreeDrawer(context);
@@ -99,8 +90,12 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
     
     return Scaffold(
       key: refreshableKey,
-      appBar: getAppBar(context),
+      appBar: AppBar(
-      drawer: null,
+        title: Text(getAppBarTitle(context)),
+        actions: getAppBarActions(context),
+        leading: backButton(context, refreshableKey),
+      ),
+      drawer: getDrawer(context),
       floatingActionButton: getFab(context),
       body: Builder(
         builder: (BuildContext context) {