flutter-login-2

优化

1.解决键盘遮挡的问题
2.解决编辑框添加clearbutton
3.添加提示框

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomepage(title: '登录',)
    );
  }
}

class MyHomepage extends StatefulWidget {
  final String title;
  MyHomepage({
    Key key,
    this.title
  }) : super(key : key);


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

class  _MyHomepageState extends State<MyHomepage> {
  bool _phoneState,_pwdState = false;
  String _checkStr;
  TextEditingController _phonecontroller = TextEditingController();
  TextEditingController _pwdcontroller = TextEditingController();
  void _checkPhone(){
    if(_phonecontroller.text.isNotEmpty && _pwdcontroller.text.trim().length == 11){
      _phoneState = true;
    }
    else {
      _phoneState = false;
    }
  }
  void _checkPwd(){
    if (_pwdcontroller.text.isNotEmpty &&
        _pwdcontroller.text.trim().length >= 6 &&
        _pwdcontroller.text.trim().length <= 10) {
      _pwdState = true;
    } else {
      _pwdState = false;
    }
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        title: Center(
          child: Text('登录页面'),
        ),
      ),

      body: ListView(
        children: <Widget>[
          Column(
            mainAxisSize: MainAxisSize.max,
            mainAxisAlignment: MainAxisAlignment.start,
            children: <Widget>[
              Padding(
                padding: EdgeInsets.all(16),
                child: Image.asset('images/icon_lau.jpeg',fit: BoxFit.fill,scale: 2,),
              ),
              Padding(
                  padding: EdgeInsets.fromLTRB(20.0, 0.0, 20.0, 15.0),
                  child:  Stack(
                    alignment: Alignment(1.0, 1.0),
                    children: <Widget>[
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                        children: <Widget>[
                          Padding(padding: EdgeInsets.fromLTRB(0.0, 0.0, 5.0, 0.0),
                            child: Image.asset('images/icon_user.jpg',width: 40,height: 40,fit: BoxFit.fill,),
                          ),
                          Expanded(
                              child: TextField(
                                decoration: InputDecoration(
                                  helperText: '请输入用户名',
                                ),
                              )
                          ),
                          IconButton(icon: Icon(Icons.clear,color: Colors.black45,), onPressed: (){
                            print('清除按钮');
                            _pwdcontroller.clear();
                          }),
                        ],
                      ),
                    ],
                  )
              ),
              Padding(
                  padding: EdgeInsets.fromLTRB(20.0, 0.0, 20.0, 15.0),
                  child:  Row(
                    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                    children: <Widget>[
                      Padding(padding: EdgeInsets.fromLTRB(0.0, 0.0, 5.0, 0.0),
                        child: Image.asset('images/icon_pass.jpg',width: 40,height: 40,fit: BoxFit.fill,),
                      ),
                      Expanded(
                          child: TextField(
                            decoration: InputDecoration(
                              helperText: '请输密码',
                              suffixIcon: IconButton(
                                  icon: Icon(Icons.clear,color: Colors.black45,),
                                  onPressed: (){
                                    _pwdcontroller.clear();
                                  }),
                            ),
                            obscureText: true,
                          )
                      ),
                    ],
                  )
              ),
              Container(
                width: 300,
                child: Card(
                    color: Colors.blue,
                    elevation: 16.0,
                    child: Center(
                      child: MaterialButton(onPressed: (){
                        print('疯狂登录吧');
                        _checkPhone();
                        _checkPwd();
                        if(_phoneState && _pwdState) {
                          _checkStr = '页面跳转下期见咯！';
                        }
                        else {
                          if(!_phoneState) {
                            _checkStr = '请输入11位手机号！';
                          }
                          if(!_pwdState){
                            _checkStr = '请输入6-10位密码！';
                          }
                        }
                        
                        showDialog(context: context,
                          barrierDismissible: false,
                          child: AlertDialog(
                            title: Text('提示'),
                            content: Text(_checkStr),
                            actions: <Widget>[
                              FlatButton(onPressed: (){
                                Navigator.pop(context);
                            }, child: Text('确定')),
                            ],
                          ),
                        );
                      },

                        child: Text('登录'),),
                    )
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}