2 лаба

lib/book.dart

@@ -0,0 +1,7 @@
+import 'main.dart';
+class Book {
+  final String title;
+  final BookRating rating;
+
+  Book(this.title, this.rating);
+}

lib/bookManager.dart

@@ -0,0 +1,17 @@
+import 'book.dart';
+class BookManager {
+  final List<Book> _books = [];
+
+  void addBook(Book book) {
+    _books.add(book);
+  }
+
+  List<Book> getBooks() {
+    return _books;
+  }
+
+  Future<void> simulateBookProcessing() async {
+    await Future.delayed(const Duration(seconds: 1));
+    print('Книга добавлена');
+  }
+}

lib/main.dart

@@ -1,4 +1,7 @@
+import 'dart:math';
 import 'package:flutter/material.dart';
+import 'book.dart';
+import 'bookManager.dart';
 
 void main() {
   runApp(const MyApp());
@@ -7,31 +10,16 @@ void main() {
 class MyApp extends StatelessWidget {
   const MyApp({super.key});
 
-  // This widget is the root of your application.
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'Flutter Demo',
+      debugShowCheckedModeBanner: false,
       theme: ThemeData(
-        // This is the theme of your application.
-        //
-        // TRY THIS: Try running your application with "flutter run". You'll see
-        // the application has a purple toolbar. Then, without quitting the app,
-        // try changing the seedColor in the colorScheme below to Colors.green
-        // and then invoke "hot reload" (save your changes or press the "hot
-        // reload" button in a Flutter-supported IDE, or press "r" if you used
-        // the command line to start the app).
-        //
-        // Notice that the counter didn't reset back to zero; the application
-        // state is not lost during the reload. To reset the state, use hot
-        // restart instead.
-        //
-        // This works for code too, not just values: Most code changes can be
-        // tested with just a hot reload.
         colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
         useMaterial3: true,
       ),
-      home: const MyHomePage(title: 'Казначеева Елизавета!'),
+      home: const MyHomePage(title: 'Книги'),
     );
   }
 }
@@ -39,87 +27,107 @@ class MyApp extends StatelessWidget {
 class MyHomePage extends StatefulWidget {
   const MyHomePage({super.key, required this.title});
 
-  // This widget is the home page of your application. It is stateful, meaning
-  // that it has a State object (defined below) that contains fields that affect
-  // how it looks.
-
-  // This class is the configuration for the state. It holds the values (in this
-  // case the title) provided by the parent (in this case the App widget) and
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
-
   final String title;
 
   @override
   State<MyHomePage> createState() => _MyHomePageState();
 }
 
-class _MyHomePageState extends State<MyHomePage> {
-  int _counter = 0;
+enum BookRating {
+  oneStar,
+  twoStars,
+  threeStars,
+  fourStars,
+  fiveStars,
+}
 
-  void _incrementCounter() {
+extension BookRatingExtension on BookRating {
+  String get displayName {
+    switch (this) {
+      case BookRating.oneStar:
+        return '★';
+      case BookRating.twoStars:
+        return '★★';
+      case BookRating.threeStars:
+        return '★★★';
+      case BookRating.fourStars:
+        return '★★★★';
+      case BookRating.fiveStars:
+        return '★★★★★';
+    }
+  }
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  Color _color = Colors.orangeAccent;
+
+  final BookManager _bookManager = BookManager();
+  List<Book> _displayedBooks = [];
+
+  void _addRandomBook() {
+    const ratings = BookRating.values;
+    final randomRating = ratings[Random().nextInt(ratings.length)];
+    final newBook = Book('Book ${_bookManager.getBooks().length + 1}', randomRating);
+    _bookManager.addBook(newBook);
     setState(() {
-      // This call to setState tells the Flutter framework that something has
-      // changed in this State, which causes it to rerun the build method below
-      // so that the display can reflect the updated values. If we changed
-      // _counter without calling setState(), then the build method would not be
-      // called again, and so nothing would appear to happen.
-      _counter++;
+      _color = Color((Random().nextDouble() * 0xFFFFFF).toInt()).withOpacity(1.0);
+      _displayedBooks.add(newBook);
     });
   }
 
   @override
   Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
     return Scaffold(
       appBar: AppBar(
-        // TRY THIS: Try changing the color here to a specific color (to
-        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
-        // change color while the other colors stay the same.
-        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
-        // Here we take the value from the MyHomePage object that was created by
-        // the App.build method, and use it to set our appbar title.
+        backgroundColor: _color,
         title: Text(widget.title),
       ),
       body: Center(
-        // Center is a layout widget. It takes a single child and positions it
-        // in the middle of the parent.
         child: Column(
-          // Column is also a layout widget. It takes a list of children and
-          // arranges them vertically. By default, it sizes itself to fit its
-          // children horizontally, and tries to be as tall as its parent.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
-          //
-          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
-          // action in the IDE, or press "p" in the console), to see the
-          // wireframe for each widget.
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
-            const Text(
-              'You have pushed the button this many times:',
-            ),
-            Text(
-              '$_counter',
-              style: Theme.of(context).textTheme.headlineMedium,
+            Expanded(
+              child: SingleChildScrollView(
+                child: Column(
+                  children: <Widget>[
+                    for (var book in _displayedBooks.reversed)
+                      Text(
+                        '${book.title} - Rating: ${book.rating.displayName}',
+                        style: const TextStyle(fontSize: 18),
+                      ),
+                  ],
+                ),
+              ),
             ),
           ],
         ),
       ),
-      floatingActionButton: FloatingActionButton(
-        onPressed: _incrementCounter,
-        tooltip: 'Increment',
-        child: const Icon(Icons.add),
-      ), // This trailing comma makes auto-formatting nicer for build methods.
+      floatingActionButton: Row(
+        mainAxisAlignment: MainAxisAlignment.end,
+        children: [
+          const SizedBox(width: 30),
+          SizedBox(
+            width: 150,
+            height: 50,
+            child: FloatingActionButton(
+              onPressed: () async {
+                _addRandomBook();
+                await _bookManager.simulateBookProcessing();
+              },
+              backgroundColor: _color,
+              child: const Text('Добавить книгу'),
+            ),
+          ),
+        ],
+      ),
     );
   }
 }
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