mvvm_flutter/lib/view/home_page.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../helper/toast.dart';
import '../helper/widget_utils.dart';
import '../view/base.dart';
import '../viewmodel/home_provide.dart';

/// Page ：HomePage
///
/// 获取其它页面传递来的参数
class HomePage extends PageProvideNode<HomeProvide> {
  /// 提供
  ///
  /// 获取参数 [title] 并生成一个[HomeProvide]对象
  HomePage(String title) : super(params: [title]);

  @override
  Widget buildContent(BuildContext context) {
    return _HomeContentPage(mProvider);
  }
}

/// View : 登录页面
///
/// 展示UI (ps:如果有UI地址，最好附上相应的链接)
/// 与用户进行交互
class _HomeContentPage extends StatefulWidget {
  final HomeProvide provide;

  _HomeContentPage(this.provide);

  @override
  State<StatefulWidget> createState() {
    return _HomeContentState();
  }
}

class _HomeContentState extends State<_HomeContentPage>
    with TickerProviderStateMixin<_HomeContentPage>
    implements Presenter {
  HomeProvide mProvide;

  /// 处理动画
  AnimationController _controller;
  Animation<double> _animation;

  static const ACTION_LOGIN = "login";

  @override
  void initState() {
    super.initState();
    mProvide = widget.provide;
    _controller = AnimationController(vsync: this, duration: const Duration(milliseconds: 300));
    _animation = Tween(begin: 295.0, end: 48.0).animate(_controller)
      ..addListener(() {
        mProvide.btnWidth = _animation.value;
      });
  }

  @override
  void dispose() {
    print('-------dispose-------');
    _controller.dispose();
    super.dispose();
  }

  @override
  void onClick(String action) {
    print("onClick:" + action);
    if (ACTION_LOGIN == action) {
      login();
    }
  }

  /// 登录
  ///
  /// 调用 [mProvide] 的 login 方法并进行订阅
  /// 请求开始时：启动动画 [AnimationStatus.forward]
  /// 请求结束时：反转动画 [AnimationStatus.reverse]
  /// 成功 ：弹出 'login success'
  /// 失败 ：[dispatchFailure] 显示错误原因
  void login() {
    final s = mProvide.login().doOnListen(() {
      _controller.forward();
    }).doOnDone(() {
      _controller.reverse();
    }).listen((_) {
      //success
      Toast.show("login success", context, type: Toast.SUCCESS);
    }, onError: (e) {
      //error
      dispatchFailure(context, e);
    });
    mProvide.addSubscription(s);
  }

  @override
  Widget build(BuildContext context) {
    print("--------build--------");
    return Material(
      child: Scaffold(
        appBar: AppBar(
          title: Text(mProvide.title),
        ),
        body: DefaultTextStyle(
          style: TextStyle(color: Colors.black),
          child: Column(
            children: <Widget>[
              TextField(
                keyboardType: TextInputType.text,
                decoration: InputDecoration(
                  contentPadding: EdgeInsets.all(10.0),
                  icon: Icon(Icons.person),
                  labelText: 'Account',
                ),
                autofocus: false,
                onChanged: (str) => mProvide.username = str,
              ),
              TextField(
                obscureText: true,
                keyboardType: TextInputType.text,
                decoration: InputDecoration(
                  contentPadding: EdgeInsets.all(10.0),
                  icon: Icon(Icons.lock),
                  labelText: 'Password',
                ),
                autofocus: false,
                onChanged: (str) => mProvide.password = str,
              ),
              const Padding(
                padding: EdgeInsets.only(top: 30.0),
              ),
              buildLoginBtnProvide(),
              const Text(
                "Response:",
                style: TextStyle(fontSize: 18),
                textAlign: TextAlign.start,
              ),
              Expanded(
                child: Container(
                  constraints: BoxConstraints(minWidth: double.infinity),
                  margin: EdgeInsets.fromLTRB(12, 12, 12, 0),
                  padding: EdgeInsets.all(5.0),
                  decoration: BoxDecoration(border: Border.all(color: Colors.blue)),
                  child: Selector<HomeProvide, String>(
                    selector: (_, data) => data.response,
                    builder: (context, value, child) {
                      // 使用Selector，当provide.notifyListeners()时,只有data.response改变的时候才会build
                      return Text(value);
                    },
                  ),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }

  /// 登录按钮
  ///
  /// 按钮宽度根据是否进行请求由[_controller]控制
  /// 当 [mProvide.loading] 为true 时 ，点击事件不生效
  Consumer<HomeProvide> buildLoginBtnProvide() {
    return Consumer<HomeProvide>(
      builder: (context, value, child) {
        // 使用 Consumer ,当provide.notifyListeners()时都会rebuild
        return CupertinoButton(
          onPressed: value.loading ? null : () => onClick(ACTION_LOGIN),
          pressedOpacity: 0.8,
          child: Container(
            alignment: Alignment.center,
            width: value.btnWidth,
            height: 48,
            decoration: BoxDecoration(
                borderRadius: BorderRadius.all(Radius.circular(30.0)),
                gradient: LinearGradient(colors: [
                  Color(0xFF686CF2),
                  Color(0xFF0E5CFF),
                ]),
                boxShadow: [BoxShadow(color: Color(0x4D5E56FF), offset: Offset(0.0, 4.0), blurRadius: 13.0)]),
            child: buildLoginChild(value),
          ),
        );
      },
    );
  }

  /// 登录按钮内部的 child
  ///
  /// 当请求进行时 [value.loading] 为 true 时,显示 [CircularProgressIndicator]
  /// 否则显示普通文本
  Widget buildLoginChild(HomeProvide value) {
    if (value.loading) {
      return const CircularProgressIndicator();
    } else {
      return FittedBox(
        fit: BoxFit.scaleDown,
        child: Text(
          'Login With Github Account',
          maxLines: 1,
          textAlign: TextAlign.center,
          overflow: TextOverflow.fade,
          style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 16.0, color: Colors.white),
        ),
      );
    }
  }
}