flutter_tracker/lib/pages/login_page.dart

import 'package:flutter/material.dart';
import 'package:flutter_tracker/dio/login_dao.dart';
import 'package:flutter_tracker/model/config.dart';
import 'package:flutter_tracker/model/user_model.dart';
import 'package:shared_preferences/shared_preferences.dart';

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

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

class _LoginPageState extends State<LoginPage> {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();
  final _formKey = GlobalKey<FormState>();

  String _username;
  String _password;

  @override
  void initState() {
    super.initState();
    loadData();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text('登录')),
        body: Padding(
          padding: EdgeInsets.symmetric(vertical: 16, horizontal: 24),
          child: Form(
            key: _formKey,
            child: Column(
              children: <Widget>[
                TextFormField(
                  autofocus: true,
                  controller: _usernameController,
                  decoration: InputDecoration(
                      labelText: '用户名',
                      hintText: '请输入用户名',
                      icon: Icon(Icons.person)),
                  validator: (value) {
                    if (value.isEmpty) {
                      return '用户名不能为空';
                    }
                    return null;
                  },
                  onSaved: (value) {
                    _username = value;
                  },
                ),
                TextFormField(
                  controller: _passwordController,
                  decoration: InputDecoration(
                      labelText: '密码',
                      hintText: '请输入密码',
                      icon: Icon(Icons.lock)),
                  obscureText: true,
                  validator: (value) {
                    if (value.isEmpty) {
                      return '密码不能为空';
                    }
                    return null;
                  },
                  onSaved: (value) {
                    _password = value;
                  },
                ),
                Padding(
                  padding: EdgeInsets.only(top: 28),
                  child: Row(
                    children: [
                      Expanded(
                        child: RaisedButton(
                          padding: EdgeInsets.all(15),
                          color: Theme.of(context).primaryColor,
                          textColor: Colors.white,
                          child: Text('登录'),
                          onPressed: () {
                            login();
                          },
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ),
          ),
        ));
  }

  void loadData() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    String username = prefs.getString('username');
    String password = prefs.getString('password');
    if (username != null && password != null) {
      _usernameController.text = username;
      _passwordController.text = password;
    }
  }

  void login() async {
    if (_formKey.currentState.validate()) {
      _formKey.currentState.save();
      UserModel userModel = await LoginDao.login(_username, _password);
      if (userModel.username == "") {
        Config.pref.setString('username', _username);
        Config.pref.setString('password', _password);
        Config.pref.setBool('isLogin', true);
        Navigator.of(context).pushReplacementNamed('/home');
      } else {}
    }
  }
}