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This extracts the sample code out from the API doc comments, and places them in separate files on disk, allowing running of the examples locally, testing them, and building of slightly larger examples.
81 lines
2.8 KiB
Dart
81 lines
2.8 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Template: dev/snippets/config/templates/freeform.tmpl
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//
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// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
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// of samples, and may be ignored if you are just exploring the sample.
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// Flutter code sample for ScrollMetricsNotification
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//
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//***************************************************************************
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//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
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// This sample shows how a [ScrollMetricsNotification] is dispatched when
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// the `windowSize` is changed. Press the floating action button to increase
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// the scrollable window's size.
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//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
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//***************************************************************************
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//*************************************************************************
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//* ▼▼▼▼▼▼▼▼ code-main ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
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import 'package:flutter/material.dart';
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void main() => runApp(const ScrollMetricsDemo());
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class ScrollMetricsDemo extends StatefulWidget {
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const ScrollMetricsDemo({Key? key}) : super(key: key);
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@override
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State<ScrollMetricsDemo> createState() => ScrollMetricsDemoState();
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}
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class ScrollMetricsDemoState extends State<ScrollMetricsDemo> {
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double windowSize = 200.0;
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@override
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Widget build(BuildContext context) {
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return MaterialApp(
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home: Scaffold(
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appBar: AppBar(
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title: const Text('ScrollMetrics Demo'),
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),
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floatingActionButton: FloatingActionButton(
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child: const Icon(Icons.add),
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onPressed: () => setState(() {
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windowSize += 10.0;
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}),
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),
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body: NotificationListener<ScrollMetricsNotification>(
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onNotification: (ScrollMetricsNotification notification) {
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ScaffoldMessenger.of(notification.context).showSnackBar(
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const SnackBar(
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content: Text('Scroll metrics changed!'),
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),
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);
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return false;
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},
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child: Scrollbar(
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isAlwaysShown: true,
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child: SizedBox(
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height: windowSize,
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width: double.infinity,
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child: const SingleChildScrollView(
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child: FlutterLogo(
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size: 300.0,
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),
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),
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),
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),
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),
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),
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);
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}
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}
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//* ▲▲▲▲▲▲▲▲ code-main ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
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//*************************************************************************
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