sliver state handler component (beta)

lib/widgets/sliver_state_handler.dart

@@ -0,0 +1,45 @@
+import 'package:didvan/models/enums.dart';
+import 'package:didvan/providers/core_provider.dart';
+import 'package:didvan/widgets/didvan/text.dart';
+import 'package:flutter/material.dart';
+
+class SliverStateHandler<T extends CoreProvier> extends SliverList {
+  final T state;
+  final Widget Function(BuildContext context, T state, int index) builder;
+  final int childCount;
+  final VoidCallback? onRefresh;
+  final bool enableEmptyState;
+  final Widget? emptyState;
+  final Widget? placeholder;
+  SliverStateHandler({
+    Key? key,
+    required this.builder,
+    required this.childCount,
+    this.placeholder,
+    this.emptyState,
+    this.enableEmptyState = false,
+    this.onRefresh,
+    required this.state,
+  }) : super(
+          key: key,
+          delegate: SliverChildBuilderDelegate(
+            (context, index) {
+              if (state.appState == AppState.failed) {
+                return const DidvanText('مشکل اتصال');
+              }
+              if (enableEmptyState) {
+                return emptyState;
+              }
+              if (state.appState == AppState.busy) {
+                return placeholder;
+              }
+              return builder(context, state, index);
+            },
+            childCount: state.appState == AppState.idle
+                ? childCount
+                : state.appState == AppState.busy
+                    ? 3
+                    : 1,
+          ),
+        );
+}