设备方向不响应 - Flutter

Question

嗨，Stackverflow Geeks，我需要帮助

我将我的应用配置为在横向模式下显示切换按钮，但我无法弄清楚为什么它不起作用

下面的条件应该可以帮助我识别风景并显示一个具有显示或不显示图表功能的开关


if (isLandscape)
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  const Text('Show Chart'),
                  Switch(
                    value: _showChart,
                    onChanged: (value) {
                      setState(() {
                        _showChart = value;
                      });
                    },
                  ),
                ],
              ),

这是我的完整代码

import 'package:expenses_app/widgets/chart.dart';
import 'package:expenses_app/widgets/transacion_list.dart';
import 'package:flutter/material.dart';
// import 'package:flutter/services.dart';
import './widgets/new_transaction.dart';
import './model/transaction.dart';

void main() {
  // ?force device to potrait mode
  // WidgetsFlutterBinding.ensureInitialized();
  // SystemChrome.setPreferredOrientations(
  //   [
  //     DeviceOrientation.portraitUp,
  //     DeviceOrientation.portraitDown,
  //   ],
  // );

  runApp(const ExpensesApp());
}

class ExpensesApp extends StatelessWidget {
  const ExpensesApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: ' expenses application',
      theme: ThemeData(
        primarySwatch: Colors.green,
        fontFamily: 'Quicksand',
        textTheme: ThemeData.light().textTheme.copyWith(
              bodyText1: const TextStyle(
                fontFamily: 'OpenSans',
                fontWeight: FontWeight.bold,
                fontSize: 20,
              ),
              button: const TextStyle(
                color: Colors.white,
                fontWeight: FontWeight.bold,
              ),
            ),
        appBarTheme: AppBarTheme(
          toolbarTextStyle: ThemeData.light().textTheme.copyWith().bodyText2,
          titleTextStyle: ThemeData.light().textTheme.copyWith().headline6,
        ),
      ),
      home: const Home(),
    );
  }
}

class Home extends StatefulWidget {
  const Home({Key? key}) : super(key: key);

  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {
  final List<Transaction> _userTransactions = [
    // Transaction(
    //   id: 't1',
    //   title: 'shoes',
    //   amount: 345,
    //   date: DateTime.now(),
    // ),
    // Transaction(
    //   id: 't2',
    //   title: 'eggs',
    //   amount: 200,
    //   date: DateTime.now(),
    // ),
  ];

  bool _showChart = false;

  List<Transaction> get _recentTransactions {
    return _userTransactions.where(
      (element) {
        return element.date.isAfter(
          DateTime.now().subtract(
            const Duration(days: 7),
          ),
        );
      },
    ).toList();
  }

  void _addTransaction(String txtitle, double txamount, DateTime chosenDate) {
    final newTransaction = Transaction(
      title: txtitle,
      amount: txamount,
      date: chosenDate,
      id: DateTime.now().toString(),
    );
    setState(() {
      _userTransactions.add(newTransaction);
    });
  }

  void _startAddingNewTransaction(BuildContext context) {
    showModalBottomSheet(
      context: context,
      builder: (_) {
        return GestureDetector(
          onTap: (() {}),
          child: NewTransaction(
            addTransaction: _addTransaction,
          ),
          behavior: HitTestBehavior.opaque,
        );
      },
    );
  }

  void _deleteTransaction(String id) {
    setState(() {
      _userTransactions.removeWhere((element) => element.id == id);
    });
  }

  @override
  Widget build(BuildContext context) {
    // ignore: unrelated_type_equality_checks
    final isLandscape = MediaQuery.of(context).orientation == Orientation;

    final varAppbar = AppBar(
      title: const Text(
        'Expenses App',
        style: TextStyle(fontFamily: 'OpenSans'),
      ),
      actions: [
        IconButton(
          onPressed: () => _startAddingNewTransaction(context),
          icon: const Icon(
            Icons.add,
          ),
        )
      ],
    );

    final transactionListWidget = SizedBox(
      height: (MediaQuery.of(context).size.height - varAppbar.preferredSize.height - MediaQuery.of(context).padding.top) * 0.75,
      child: TransactionList(
        transactions: _userTransactions,
        deleteTransaction: _deleteTransaction,
      ),
    );

    return Scaffold(
      backgroundColor: Theme.of(context).primaryColorLight,
      appBar: varAppbar,
      body: SingleChildScrollView(
        child: Column(
          children: [
            if (isLandscape)
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  const Text('Show Chart'),
                  Switch(
                    value: _showChart,
                    onChanged: (value) {
                      setState(() {
                        _showChart = value;
                      });
                    },
                  ),
                ],
              ),
            if (!isLandscape)
              SizedBox(
                height: (MediaQuery.of(context).size.height - varAppbar.preferredSize.height - MediaQuery.of(context).padding.top) * 0.25,
                child: Chart(recentTransactions: _recentTransactions),
              ),
            if (!isLandscape) transactionListWidget,
            if (isLandscape)
              _showChart
                  ? SizedBox(
                      height: (MediaQuery.of(context).size.height - varAppbar.preferredSize.height - MediaQuery.of(context).padding.top) * 1,
                      child: Chart(recentTransactions: _recentTransactions),
                    )
                  : transactionListWidget,
          ],
        ),
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
      floatingActionButton: FloatingActionButton(
        onPressed: () => _startAddingNewTransaction(context),
        child: const Icon(Icons.add),
      ),
    );
  }
}

Answer 1

// ignore: unrelated_type_equality_checks
final isLandscape = MediaQuery.of(context).orientation == Orientation;

//change that to

final isLandscape = MediaQuery.of(context).orientation == Orientation.landscape;

设备方向不响应 - Flutter

Device Orientation Not Responding- Flutter

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