Main screen loading indicator (#183)

* Bug fix for login screen

- Prevent setState() from being called if the widget is no longer loaded

* Add callback function when API status changes

- Home screen uses this function to update connection status indicator

* Linting fixes

assets/release_notes.md

@@ -9,6 +9,7 @@
 - Indicate available quantity in stock detail view
 - Adds configurable filtering to various list views
 - Allow stock location to be "scanned" into another location using barcode
+- Improves server connection status indicator on home screen
 
 ### 0.7.3 - June 2022
 ---

lib/api.dart

@@ -135,6 +135,9 @@ class InvenTreeFileService extends FileService {
  */
 
 
+/*
+ * API class which manages all communication with the InvenTree server
+ */
 class InvenTreeAPI {
 
   factory InvenTreeAPI() {
@@ -143,6 +146,19 @@ class InvenTreeAPI {
 
   InvenTreeAPI._internal();
 
+  // List of callback functions to trigger when the connection status changes
+  List<Function()> _statusCallbacks = [];
+
+  // Register a callback function to be notified when the connection status changes
+  void registerCallback(Function() func) => _statusCallbacks.add(func);
+
+  void _connectionStatusChanged() {
+    for (Function() func in _statusCallbacks) {
+      // Call the function
+      func();
+    }
+  }
+
   // Minimum required API version for server
   static const _minApiVersion = 20;
 
@@ -202,6 +218,10 @@ class InvenTreeAPI {
   // Authentication token (initially empty, must be requested)
   String _token = "";
 
+  String? get serverAddress {
+    return profile?.server;
+  }
+
   bool get hasToken => _token.isNotEmpty;
 
   /*
@@ -457,6 +477,8 @@ class InvenTreeAPI {
     // Clear received settings
     _globalSettings.clear();
     _userSettings.clear();
+
+    _connectionStatusChanged();
   }
 
   /*
@@ -481,6 +503,8 @@ class InvenTreeAPI {
 
     _connecting = true;
 
+    _connectionStatusChanged();
+
     _connected = await _connect();
 
     _connecting = false;
@@ -493,6 +517,8 @@ class InvenTreeAPI {
       );
     }
 
+    _connectionStatusChanged();
+
     return _connected;
   }
 

lib/l10n/app_en.arb

@@ -908,6 +908,9 @@
   "serverNotConnected": "Server not connected",
   "@serverNotConnected": {},
 
+  "serverNotSelected": "Server not selected",
+  "@serverNotSelected": {},
+
   "sounds": "Sounds",
   "@sounds": {},
 

lib/settings/login.dart

@@ -29,6 +29,10 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
 
     profiles = await UserProfileDBManager().getAllProfiles();
 
+    if (!mounted) {
+      return;
+    }
+
     setState(() {
     });
   }
@@ -58,6 +62,10 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
 
     await UserProfileDBManager().selectProfile(key);
 
+    if (!mounted) {
+      return;
+    }
+
     _reload();
 
     // Attempt server login (this will load the newly selected profile
@@ -72,6 +80,10 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
 
     await UserProfileDBManager().deleteProfile(profile);
 
+    if (!mounted) {
+      return;
+    }
+
     _reload();
 
     if (InvenTreeAPI().isConnected() && profile.key == (InvenTreeAPI().profile?.key ?? "")) {

lib/widget/home.dart

@@ -23,6 +23,7 @@ import "package:inventree/widget/part_list.dart";
 import "package:inventree/widget/purchase_order_list.dart";
 import "package:inventree/widget/search.dart";
 import "package:inventree/widget/snacks.dart";
+import "package:inventree/widget/spinner.dart";
 
 
 class InvenTreeHomePage extends StatefulWidget {
@@ -51,6 +52,13 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
         ), (timer) {
       _refreshNotifications();
     });
+
+    InvenTreeAPI().registerCallback(() {
+      setState(() {
+        // Reload the widget
+      });
+    });
+
   }
 
   // Index of bottom navigation bar
@@ -352,6 +360,24 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
    * display a connection status widget
    */
   Widget _connectionStatusWidget(BuildContext context) {
+
+    String? serverAddress = InvenTreeAPI().serverAddress;
+    bool validAddress = serverAddress != null;
+    bool connecting = !InvenTreeAPI().isConnected() && InvenTreeAPI().isConnecting();
+
+    Widget leading = FaIcon(FontAwesomeIcons.exclamationCircle, color: COLOR_DANGER);
+    Widget trailing = FaIcon(FontAwesomeIcons.server, color: COLOR_CLICK);
+    String title = L10().serverNotConnected;
+    String subtitle = L10().profileSelectOrCreate;
+
+    if (!validAddress) {
+      title = L10().serverNotSelected;
+    } else if (connecting) {
+      title = L10().serverConnecting;
+      subtitle = serverAddress;
+      leading = Spinner(icon: FontAwesomeIcons.spinner, color: COLOR_PROGRESS);
+    }
+
     return Center(
       child: Column(
         children: [
@@ -363,10 +389,10 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
           ),
           Spacer(),
           ListTile(
-            title: Text(L10().serverNotConnected),
+            title: Text(title),
-            subtitle: Text(L10().profileSelectOrCreate),
+            subtitle: Text(subtitle),
-            trailing: FaIcon(FontAwesomeIcons.server, color: COLOR_CLICK),
+            trailing: trailing,
-            leading: FaIcon(FontAwesomeIcons.exclamationCircle, color: COLOR_DANGER),
+            leading: leading,
             onTap: _selectProfile,
           )
         ]
@@ -456,6 +482,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
   Widget build(BuildContext context) {
 
     var connected = InvenTreeAPI().isConnected();
+    var connecting = !connected && InvenTreeAPI().isConnecting();
 
     return Scaffold(
       key: _homeKey,
@@ -465,7 +492,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
           IconButton(
             icon: FaIcon(
               FontAwesomeIcons.server,
-              color: connected ? COLOR_SUCCESS : COLOR_DANGER,
+              color: connected ? COLOR_SUCCESS : (connecting ? COLOR_PROGRESS: COLOR_DANGER),
             ),
             onPressed: _selectProfile,
           )