Question

我有一个Widget MainPage，它使用AppBar和bottomNavigationBar构建一个Scaffold。作为主体，我有一个IndexedStack并仅呈现当前活动的tab-widget。每个选项卡都从Rest-API加载一些数据并显示数据。

当前，我正在尝试向MainPage中的AppBar添加一个重新加载按钮，但是我的问题是如何告诉子小部件它们应该重新加载数据。

MainPage看起来像这样：

import 'package:flutter/material.dart';
import 'package:iracingdata/Last10Races.dart';
import 'package:iracingdata/MyLicenses.dart';
import 'package:iracingdata/Utils.dart';
import 'package:iracingdata/main.dart';

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

  @override
  State<StatefulWidget> createState() => _MainState();
}

class _MainState extends State<MainPage> {
  int _currentIndex = 0;
  List<Widget> _children;

  @override
  void initState() {
    super.initState();
    _children = [Last10Races(), MyLicenses()];
  }

  void _onTabTapped(int tabIndex) {
    setState(() { _currentIndex = tabIndex; });
  }

  void _onRefresh() {
    // TODO: What to do here?
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Hallo ${Utils.decodeString(AppContainer.apiOf(context).playerInfo.displayName)}'),
        actions: <Widget>[
          FlatButton(
            onPressed: _onRefresh,
            child: Icon(Icons.refresh, color: Colors.white),
          )
        ],
      ),
      body: IndexedStack(
        index: _currentIndex,
        children: _children,
      ),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _currentIndex,
        onTap: _onTabTapped,
        items: [
          BottomNavigationBarItem(
            icon: new Icon(Icons.assignment),
            title: new Text('Last Races'),
          ),
          BottomNavigationBarItem(
            icon: new Icon(Icons.person),
            title: new Text('My Licenses'),
          ),
        ],
      ),
    );
  }
}

其中一个子页面如下所示：

import 'package:flutter/material.dart';
import 'package:iracingdata/main.dart';
import 'package:iracingdata/model/LastRacesStats.dart';

class Last10Races extends StatefulWidget {
  Last10Races({Key key}) : super(key: key);

  @override
  State<StatefulWidget> createState() => _Last10RacesState();
}

class _Last10RacesState extends State<Last10Races> {
  Future<List<LastRacesStats>> _lastRacesFuture;

  @override
  void didChangeDependencies() {
    if (_lastRacesFuture == null) {
      _lastRacesFuture = AppContainer.apiOf(context).getLast10RacesStats();
    }
    super.didChangeDependencies();
  }

  void _reload() {
    setState(() {
      _lastRacesFuture = AppContainer.apiOf(context).getLast10RacesStats();
    });
  }

  Widget _renderItem(LastRacesStats item) {
    return Text(item.name);
  }

  Widget _renderError() {
    return Text('Error');
  }

  Widget _renderLoading() {
    return Text('Loading...');
  }

  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _lastRacesFuture,
      initialData: null,
      builder:
          (BuildContext context, AsyncSnapshot<List<LastRacesStats>> snapshot) {
        if (snapshot.hasData) {
          return RefreshIndicator(
            onRefresh: () {
              _reload();
              return _lastRacesFuture;
            },
            child: ListView.builder(
              itemCount: snapshot.data.length,
              itemBuilder: (BuildContext context, int index) {
                return _renderItem(snapshot.data[index]);
              },
            ),
          );
        } else if (snapshot.hasError) {
          return _renderError();
        } else {
          return _renderLoading();
        }
      },
    );
  }
}

我的问题是我真的不知道要在MainPage的_onRefresh中做什么。

感谢您的帮助。

在AppBar-Action上的TabBar-Page中触发重新加载

0 个答案: