ui backbone

lib/features/core/widgets/mcg_scaffold.dart

@@ -1,5 +1,4 @@
-import 'dart:async';
-
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 
@@ -9,7 +8,7 @@ import '../services/connection_service.dart';
 class McgScaffold extends StatelessWidget {
   const McgScaffold({
     this.appBar,
-    this.bodyBuilderCompleter,
+    this.bodyBuilderWaiter,
     this.body,
     this.waitingWidget,
     this.forceInternetCheck = false,
@@ -19,10 +18,10 @@ class McgScaffold extends StatelessWidget {
   final AppBar? appBar;
 
   /// Awaits an external signal (complete) before building the body.
-  final Completer? bodyBuilderCompleter;
+  final ValueListenable<bool>? bodyBuilderWaiter;
   final Widget? body;
 
-  /// Custom widget to be used while awaiting [bodyBuilderCompleter].
+  /// Custom widget to be used while awaiting [bodyBuilderWaiter].
   ///
   /// Defaults to using [PlatformCircularProgressIndicator].
   final Widget? waitingWidget;
@@ -32,19 +31,12 @@ class McgScaffold extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final Widget loginOptionsBody = bodyBuilderCompleter != null
-        ? FutureBuilder(
-            future: bodyBuilderCompleter!.future,
-            builder: (context, snapshot) {
-              switch (snapshot.connectionState) {
-                case ConnectionState.none:
-                case ConnectionState.waiting:
-                case ConnectionState.active:
-                  return Center(child: waitingWidget ?? const CircularProgressIndicator());
-                case ConnectionState.done:
-                  return body ?? const SizedBox.shrink();
-              }
-            },
+    final Widget loginOptionsBody = bodyBuilderWaiter != null
+        ? ValueListenableBuilder<bool>(
+            valueListenable: bodyBuilderWaiter!,
+            builder: (context, final isReady, child) => !isReady
+                ? Center(child: waitingWidget ?? const CircularProgressIndicator())
+                : body ?? const SizedBox.shrink(),
           )
         : body ?? const SizedBox.shrink();
 

lib/features/core/widgets/view_model_builder.dart

@@ -0,0 +1,47 @@
+import 'package:flutter/widgets.dart';
+import 'package:provider/provider.dart';
+
+import '../abstracts/base_view_model.dart';
+
+class ViewModelBuilder<T extends BaseViewModel> extends StatefulWidget {
+  const ViewModelBuilder({
+    required Widget Function(BuildContext context, T model) builder,
+    required T Function() viewModelBuilder,
+    dynamic Function()? argumentBuilder,
+    super.key,
+  })  : _builder = builder,
+        _viewModelBuilder = viewModelBuilder,
+        _argumentBuilder = argumentBuilder;
+
+  final Widget Function(BuildContext context, T model) _builder;
+  final T Function() _viewModelBuilder;
+  final dynamic Function()? _argumentBuilder;
+
+  @override
+  _ViewModelBuilderState<T> createState() => _ViewModelBuilderState<T>();
+}
+
+class _ViewModelBuilderState<T extends BaseViewModel> extends State<ViewModelBuilder<T>> {
+  late final T _viewModel;
+
+  @override
+  void initState() {
+    _viewModel = widget._viewModelBuilder();
+    _viewModel.initialise(() => mounted, widget._argumentBuilder?.call());
+    super.initState();
+  }
+
+  @override
+  void dispose() {
+    _viewModel.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext _) => ChangeNotifierProvider.value(
+        value: _viewModel,
+        child: Consumer<T>(
+          builder: (context, model, _) => widget._builder(context, model),
+        ),
+      );
+}