我想知道怎么让android一直保持横屏状态不要一打开应用后又切换到竖屏如果是关闭设置里面的自动旋转屏幕之

Posted 2023-04-22

我想知道怎么让android一直保持横屏状态不要一打开应用后又切换到竖屏如果是关闭设置里面的自动旋转屏幕之类的就免了

在AndroidManifest.xml的activity(需要禁止转向的activity)配置中加入android:screenOrientation=”landscape”属性即可(landscape是横向，portrait是纵向)。
如果你不是开发人员就找个反编译工具，对反编译得出的AndroidManifest.xml修改，然后再编译成应用。 参考技术A setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE););//强制为横屏
或者在AndroidManifest.xml 里面添加android:screenOrientation=”landscape” 参考技术B OnCreate里面加入：
//设置为横屏
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

让用户保持登录状态

【中文标题】让用户保持登录状态

【英文标题】：Keep the user logged in flutter

【发布时间】：2020-11-23 11:05:03

【问题描述】：

我正在做一个应用程序，我正在处理身份验证部分。我想知道在我重新加载应用程序后如何让我的用户保持登录状态。这是我用于记录的代码，我已经使用了共享首选项，但仍然无法正常工作。我应该在代码中添加什么或更改？我也应该在 Homepage() 中添加一些内容吗？ 我忘了提到当我打开应用程序时我的第一页是 main.dart，第二个是 LoginScreen（您可以在其中选择您登录的帐户类型：facebook、google、电子邮件）

import 'package:flutter/material.dart';
import 'SignUp.dart';
import 'brazierContainer.dart';
import 'package:google_fonts/google_fonts.dart';
import 'LoginScreen.dart';
import 'HomePage.dart';
import 'auth.dart';
import 'package:shared_preferences/shared_preferences.dart';

Future<void> main() async 
  WidgetsFlutterBinding.ensureInitialized();
  SharedPreferences prefs = await SharedPreferences.getInstance();
  var email = prefs.getString('email');
  print(email);
  runApp(MaterialApp(home: email == null ? LoginPage() : Homepage()));


class LoginPage extends StatefulWidget 
  LoginPage(Key key, this.title) : super(key: key);

  final String title;

  @override
  _LoginPageState createState() => _LoginPageState();


class _LoginPageState extends State<LoginPage> 
  final _formKey = GlobalKey<FormState>();
  String email = '';
  String password = '';
  String error = '';
  bool loading = false;
  final Authentication authentication = Authentication();
  @override
  Widget build(BuildContext context) 
    return loading
        ? Homepage()
        : Scaffold(
            resizeToAvoidBottomInset: false,
            resizeToAvoidBottomPadding: false,
            body: Container(
              height: 900.0,
              width: 500.0,
              child: Column(
                children: <Widget>[
                  Padding(
                    padding: const EdgeInsets.only(top: 50.0),
                    child: Row(
                      children: <Widget>[
                        IconButton(
                          icon: Icon(Icons.arrow_back_ios, color: Colors.blue),
                          onPressed: () 
                            Navigator.pushReplacement(
                                context,
                                MaterialPageRoute(
                                    builder: (context) => LoginScreen()));
                          ,
                        )
                      ],
                    ),
                  ),
                  Padding(
                    padding: const EdgeInsets.only(top: 40.0),
                    child: RichText(
                      text: TextSpan(
                        text: 'Tariffo',
                        style: TextStyle(
                            color: Colors.blue,
                            fontFamily: 'SignPainter',
                            fontSize: 60),
                      ),
                    ),
                  ),
                  SizedBox(
                      height: 400.0,
                      child: Form(
                        key: _formKey,
                        child: Column(
                          children: <Widget>[
                            Padding(
                              padding: const EdgeInsets.only(
                                  left: 40.0, right: 40.0, top: 40.0),
                              child: TextFormField(
                                validator: (val) =>
                                    val.isEmpty ? 'enter email' : null,
                                onChanged: (val) 
                                  setState(() => email = val);
                                ,
                                style: TextStyle(color: Colors.black),
                                decoration: InputDecoration(
                                    hintText: 'enter email',
                                    hintStyle: TextStyle(
                                        fontFamily: 'Antra',
                                        fontSize: 12.0,
                                        color: Colors.black)),
                              ),
                            ),
                            Padding(
                              padding: const EdgeInsets.only(
                                  left: 40.0, right: 40.0, top: 40.0),
                              child: TextFormField(
                                validator: (val) => val.length < 8
                                    ? 'enter password > 8 digits'
                                    : null,
                                onChanged: (val) 
                                  setState(() => password = val);
                                ,
                                style: TextStyle(color: Colors.black),
                                decoration: InputDecoration(
                                    hintText: 'enter password',
                                    hintStyle: TextStyle(
                                        fontFamily: 'Antra',
                                        fontSize: 12.0,
                                        color: Colors.black)),
                                obscureText: true,
                              ),
                            ),
                            SizedBox(height: 50),
                            Padding(
                              padding: const EdgeInsets.only(top: 40.0),
                              child: MaterialButton(
                                height: 50,
                                minWidth: 300,
                                shape: RoundedRectangleBorder(
                                    borderRadius: BorderRadius.circular(10)),
                                color: Colors.blue,
                                onPressed: () async 
                                  SharedPreferences prefs =
                                      await SharedPreferences.getInstance();
                                  prefs.setString(
                                      'email', '[e-mail]');
                                  if (_formKey.currentState.validate()) 
                                    setState(() => loading = true);
                                    dynamic result = await authentication
                                        .signUpWithEmailAndPassword(
                                            email, password);
                                    if (result == null) 
                                      setState(() => error =
                                          'Sorry,These credentials will not work out');
                                      loading = false;
                                    
                                  
                                ,
                                child: Text(
                                  'Sign in',
                                  style: TextStyle(
                                      fontFamily: 'Antra', color: Colors.white),
                                ),
                              ),
                            ),
                            Container(
                              padding: EdgeInsets.symmetric(
                                  vertical: 10, horizontal: 10),
                              alignment: Alignment.centerRight,
                              child: Text('Forgot Password ?',
                                  style: TextStyle(
                                      fontSize: 14,
                                      fontWeight: FontWeight.w500)),
                            ),
                          ],
                        ),
                      )),
                  _createAccountLabel(),
                ],
              ),
            ),
          );
  

  Widget _createAccountLabel() 
    return InkWell(
      onTap: () 
        Navigator.push(
            context, MaterialPageRoute(builder: (context) => SignupPage()));
      ,
      child: Container(
        margin: EdgeInsets.symmetric(vertical: 20),
        padding: EdgeInsets.all(15),
        alignment: Alignment.bottomCenter,
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              "Don't you have an account ?",
              style: TextStyle(fontSize: 13, fontWeight: FontWeight.w600),
            ),
            SizedBox(
              width: 10,
            ),
            Text(
              'Register',
              style: TextStyle(
                  color: Colors.blue,
                  fontSize: 13,
                  fontWeight: FontWeight.w600),
            ),
          ],
        ),
      ),
    );
  

还有我的 main.dart

import 'package:flutter/material.dart';
import 'dart:async';
import 'LoginScreen.dart';

void main() => runApp(new MaterialApp(
      home: new MyApp(),
    ));

class MyApp extends StatefulWidget 
  @override
  _MyAppState createState() => new _MyAppState();


class _MyAppState extends State<MyApp> 
  @override
  void initState() 
    super.initState();
    new Future.delayed(
        const Duration(seconds: 3),
        () => Navigator.push(
              context,
              MaterialPageRoute(builder: (context) => LoginScreen()),
            ));
  

  @override
  Widget build(BuildContext context) 
    return MaterialApp(
      title: 'Welcome to Flutter',
      home: Scaffold(
          backgroundColor: Colors.blue,
          body: Center(
            child: Text(
              "Tariffo",
              style: TextStyle(
                  color: Colors.white, fontFamily: 'SignPainter', fontSize: 60),
            ),
          )),
    );
  

【参考方案1】：

您必须显示 main.dart 文件 您是否从 main.dart 中的 SharedPreferences 下载信息？如果是这样，您需要在进入登录页面之前检查您是否已经从 SharedPreferences 下载了一些数据，并且不要打开登录页面。

【讨论】：

在主要飞镖我只有应用程序的标志

并重定向到登录页面，对吗？显示这个文件，我会写下如何让它工作

Main.dart -> LoginScreen.dart -> SignUp.dart -> LoginPage.dart -> Homepage.dart

@svraluca1 好的，您必须在 main.dart 文件中检查 sharedPreferences 是否为空 - 如果不为空，请不要重定向到 loginPage String _email; SharedPreferences sharedPrefs; sharedPrefs = await SharedPreferences.getInstance(); email = sharedPrefs.getString('email') ?? ''; if ('' == email) Navigator.push( context, MaterialPageRoute(builder: (context) => LoginScreen()), )

@svraluca1 当然，您将电子邮件更改为 _email - 我的错。并在你使用路由的地方使用这个if... - initState 代替new Future.delayed( const Duration(seconds: 3), () => Navigator.push( context, MaterialPageRoute(builder: (context) => LoginScreen()), ));