VB10 · May 28, 2024 22:22 · May 28, 2024
diff --git a/error_manage_widget_with_exception.dart b/error_manage_widget_with_exception.dart
@@ -0,0 +1,127 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+
+class User {
+  final String? name;
+  final int? age;
+
+  const User(this.name, this.age);
+
+  bool isEmpty() {
+    return name == null || age == null;
+  }
+
+  MapEntry<String, int> get nameAndAge {
+    if (isEmpty()) CustomException.instance.throwException('User not found');
+    return MapEntry(name!, age!);
+  }
+}
+
+class HomeView extends StatefulWidget {
+  const HomeView({super.key});
+
+  @override
+  State<HomeView> createState() => _HomeViewState();
+}
+
+class _HomeViewState extends State<HomeView> with _HomeViewMixin {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('HomeView'),
+      ),
+      body: _users == null
+          ? const Center(
+              child: CircularProgressIndicator(),
+            )
+          : _UserListView(users: _users!),
+    );
+  }
+}
+
+class _UserListView extends StatelessWidget {
+  const _UserListView({required this.users});
+
+  final List<User> users;
+
+  @override
+  Widget build(BuildContext context) {
+    return ListView.builder(
+      itemCount: users.length,
+      itemBuilder: (context, index) {
+        return UserCard(user: users[index]);
+      },
+    );
+  }
+}
+
+mixin _HomeViewMixin on State<HomeView> {
+  List<User>? _users;
+
+  Future<void> fetchUser() async {
+    final backendResponse = List<User?>.generate(
+      10,
+      (index) {
+        if (index.isOdd) return null;
+        return User('User $index', index);
+      },
+    );
+    await Future.delayed(Durations.short1);
+
+    /// 1
+    _users = backendResponse
+        .where((element) => element != null)
+        .cast<User>()
+        .toList();
+
+    setState(() {});
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    fetchUser();
+  }
+}
+
+class UserCard extends StatelessWidget {
+  const UserCard({super.key, required this.user});
+  final User user;
+
+  /// yasi 30dan buyukse sol taraf yesil olacak kirmizi
+  /// title olarak adi gozukecek
+  /// age gozukecek
+  @override
+  Widget build(BuildContext context) {
+    final latestUserData = user.nameAndAge;
+    return ListTile(
+      title: Text(latestUserData.key),
+      subtitle: Text(latestUserData.value.toString()),
+      leading: Container(
+        width: 50,
+        height: 50,
+        color: latestUserData.value > 30 ? Colors.green : Colors.red,
+      ),
+    );
+  }
+}
+
+abstract class CustomException {
+  void throwException(String message);
+  static CustomException get instance =>
+      kDebugMode ? DevelopmentException() : ProductionException();
+}
+
+class DevelopmentException implements CustomException {
+  @override
+  void throwException(String message) {
+    throw Exception(message);
+  }
+}
+
+class ProductionException implements CustomException {
+  /// custom end point
+  @override
+  void throwException(String message) {}
+}