FlutterDemo合集.7z

import 'package:flutter/material.dart'; import 'package:provider/provider.dart'; import 'package:provider_example/order_provider.dart'; import 'color_model.dart'; import 'counter_model.dart'; import 'goods_model.dart'; class FirstScreen extends StatelessWidget { @override Widget build(BuildContext context) { final counter = Provider.of<CounterModel>( context, ); final textSize = Provider.of<int>(context); return Scaffold( appBar: AppBar( title: Text('First Page'), ), body: Center( child: Text( 'Value: ${counter.value}', style: TextStyle( fontSize: textSize.toDouble(), ), ), ), floatingActionButton: FloatingActionButton( onPressed: () => Navigator.of(context).push(MaterialPageRoute(builder: (context) => SecondScreen())), child: Icon(Icons.navigate_next), ), ); } } /// This is a single page provider, /// it will be destroyed when the page is removed, /// and the status will be reset. class SecondScreenProvider extends StatefulWidget { final Widget child; SecondScreenProvider({@required this.child}); @override _SecondScreenProviderState createState() => _SecondScreenProviderState(); } class _SecondScreenProviderState extends State<SecondScreenProvider> { ColorModel _colorModel = ColorModel(); @override Widget build(BuildContext context) { return ChangeNotifierProvider.value( value: _colorModel, child: widget.child, ); } } class SecondScreen extends StatelessWidget { @override Widget build(BuildContext context) { return SecondScreenProvider( child: DefaultTabController( length: 3, child: Scaffold( appBar: buildAppBar(), body: TabBarView(children: [ buildCounterText(), showIconWithColor(), showIconWithColor(), ]), floatingActionButton: buildActionButtons(), ), ), ); } Column buildActionButtons() { return Column( mainAxisAlignment: MainAxisAlignment.end, children: <Widget>[ Consumer<ColorModel>( builder: (context, ColorModel colorModel, child) { return FloatingActionButton( heroTag: 'no_hero', child: Icon(Icons.swap_horizontal_circle), onPressed: () { colorModel.changeColor(); }, ); }, ), SizedBox(height: 20), Consumer<CounterModel>( builder: (context, CounterModel counter, child) => FloatingActionButton( onPressed: () => counter.increment(), child: child, ), child: Icon(Icons.add), ), ], ); } Consumer2<CounterModel, int> buildCounterText() { return Consumer2<CounterModel, int>( builder: (context, CounterModel counter, int textSize, child) { return Center( child: Text( 'Value: ${counter.value}', style: TextStyle( fontSize: textSize.toDouble(), ), ), ); }, ); } AppBar buildAppBar() { return AppBar( title: Text('Second Page'), bottom: TabBar(tabs: [ Tab(text: 'show counter'), Tab(text: 'show color'), Tab(text: 'show color'), ]), ); } Container showIconWithColor() { return Container( alignment: Alignment.center, child: Consumer<ColorModel>( builder: (context, ColorModel colorModel, child) { return Icon( Icons.stars, color: colorModel.color, size: 100, ); }, ), ); } } class GoodsListScreen extends StatelessWidget { @override Widget build(BuildContext context) { return ChangeNotifierProvider( create: (_) => GoodsListProvider(), child: Scaffold( body: Selector<GoodsListProvider, GoodsListProvider>( shouldRebuild: (pre, next) => pre.shouldRebuild, selector: (context, provider) => provider, builder: (context, provider, child) { provider.rebuild(); return ListView.builder( itemCount: provider.total, itemBuilder: (context, index) { return Selector<GoodsListProvider, Goods>( selector: (context, provider) => provider.goodsList[index], builder: (context, data, child) { print(('No.${index + 1} rebuild')); return ListTile( title: Text(data.goodsName), trailing: GestureDetector( onTap: () => provider.collect(index), child: Icon(data.isCollection ? Icons.star : Icons.star_border), ), ); }, ); }, ); }, ), floatingActionButton: Consumer<GoodsListProvider>( builder: (context, GoodsListProvider model, child) { return FloatingActionButton( child: Icon(Icons.add), onPressed: () { model.addAll(); }, ); }, ), ), ); } } class OrderListScreen extends StatefulWidget { @override _OrderListScreenState createState() => _OrderListScreenState(); } class _OrderListScreenState extends State<OrderListScreen> { OrderProvider _provider = OrderProvider(); @override Widget build(BuildContext context) { return ChangeNotifierProvider.value( value: _provider, child: Scaffold( body: Selector<OrderProvider, List<Order>>( selector: (BuildContext _, OrderProvider provider) => provider.orderList, builder: (BuildContext _, List<Order> orderList, Widget __) { return ListView.builder( itemCount: _provider.listSize, itemBuilder: (context, index) { return Selector<OrderProvider, Order>( selector: (BuildContext _, OrderProvider provider) => provider.orderList[index], builder: (BuildContext _, Order data, Widget __) { print(('No.${index + 1} rebuild')); return ListTile( title: Text(data.goodsName), trailing: GestureDetector( onTap: () => _provider.collect(index), child: Icon(data.isCollection ? Icons.star : Icons.star_border), ), ); }, ); }, ); }, ), floatingActionButton: Consumer<OrderProvider>( builder: (BuildContext _, OrderProvider provider, Widget __) { return FloatingActionButton( child: Icon(Icons.add), onPressed: () { provider.addAll(); }, ); }, ), ), ); } }