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samples/platform_design/lib/songs_tab.dart

170 lines
4.7 KiB

import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'song_detail_tab.dart';
import 'utils.dart';
import 'widgets.dart';
class SongsTab extends StatefulWidget {
static const title = 'Songs';
static const androidIcon = Icon(Icons.music_note);
static const iosIcon = Icon(CupertinoIcons.music_note);
const SongsTab({Key key, this.androidDrawer}) : super(key: key);
final Widget androidDrawer;
@override
_SongsTabState createState() => _SongsTabState();
}
class _SongsTabState extends State<SongsTab> {
static const _itemsLength = 50;
final _androidRefreshKey = GlobalKey<RefreshIndicatorState>();
List<MaterialColor> colors;
List<String> songNames;
@override
void initState() {
_setData();
super.initState();
}
void _setData() {
colors = getRandomColors(_itemsLength);
songNames = getRandomNames(_itemsLength);
}
Future<void> _refreshData() {
return Future.delayed(
// This is just an arbitrary delay that simulates some network activity.
const Duration(seconds: 2),
() => setState(() => _setData()),
);
}
Widget _listBuilder(BuildContext context, int index) {
if (index >= _itemsLength) return null;
// Show a slightly different color palette. Show poppy-ier colors on iOS
// due to lighter contrasting bars and tone it down on Android.
final color = defaultTargetPlatform == TargetPlatform.iOS
? colors[index]
: colors[index].shade400;
return SafeArea(
top: false,
bottom: false,
child: Hero(
tag: index,
child: HeroAnimatingSongCard(
song: songNames[index],
color: color,
heroAnimation: AlwaysStoppedAnimation(0),
onPressed: () => Navigator.of(context).push<void>(
MaterialPageRoute(
builder: (context) => SongDetailTab(
id: index,
song: songNames[index],
color: color,
),
),
),
),
),
);
}
void _togglePlatform() {
TargetPlatform _getOppositePlatform() {
if (defaultTargetPlatform == TargetPlatform.iOS) {
return TargetPlatform.android;
} else {
return TargetPlatform.iOS;
}
}
debugDefaultTargetPlatformOverride = _getOppositePlatform();
// This rebuilds the application. This should obviously never be
// done in a real app but it's done here since this app
// unrealistically toggles the current platform for demonstration
// purposes.
WidgetsBinding.instance.reassembleApplication();
}
// ===========================================================================
// Non-shared code below because:
// - Android and iOS have different scaffolds
// - There are differenc items in the app bar / nav bar
// - Android has a hamburger drawer, iOS has bottom tabs
// - The iOS nav bar is scrollable, Android is not
// - Pull-to-refresh works differently, and Android has a button to trigger it too
//
// And these are all design time choices that doesn't have a single 'right'
// answer.
// ===========================================================================
Widget _buildAndroid(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(SongsTab.title),
actions: [
IconButton(
icon: Icon(Icons.refresh),
onPressed: () async => await _androidRefreshKey.currentState.show(),
),
IconButton(
icon: Icon(Icons.shuffle),
onPressed: _togglePlatform,
),
],
),
drawer: widget.androidDrawer,
body: RefreshIndicator(
key: _androidRefreshKey,
onRefresh: _refreshData,
child: ListView.builder(
padding: EdgeInsets.symmetric(vertical: 12),
itemBuilder: _listBuilder,
),
),
);
}
Widget _buildIos(BuildContext context) {
return CustomScrollView(
slivers: [
CupertinoSliverNavigationBar(
trailing: CupertinoButton(
padding: EdgeInsets.zero,
child: Icon(CupertinoIcons.shuffle),
onPressed: _togglePlatform,
),
),
CupertinoSliverRefreshControl(
onRefresh: _refreshData,
),
SliverSafeArea(
top: false,
sliver: SliverPadding(
padding: EdgeInsets.symmetric(vertical: 12),
sliver: SliverList(
delegate: SliverChildBuilderDelegate(_listBuilder),
),
),
),
],
);
}
@override
Widget build(context) {
return PlatformWidget(
androidBuilder: _buildAndroid,
iosBuilder: _buildIos,
);
}
}