125 lines
3.7 KiB
Markdown
125 lines
3.7 KiB
Markdown
[](https://github.com/fluttercommunity/community)
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[](https://www.buymeacoffee.com/rodydavis)
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[](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=WSH3GVC49GNNJ)
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[](https://github.com/fluttercommunity/breakpoint)
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[](https://pub.dev/packages/breakpoint)
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# breakpoint
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View the online demo [here](https://fluttercommunity.github.io/breakpoint/#/)!
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## Overview
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Follows Material Design [Docs](https://material.io/design/layout/responsive-layout-grid.html#breakpoints).
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## Usage
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When you are wanting to calculate the breakpoint of a widget that may not take up the full screen. This needs `BoxConstraints` but can be provided by the layout builder.
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``` dart
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final _breakpoint = Breakpoint.fromConstraints(constraints);
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```
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When a widget always takes up thye full screen.
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``` dart
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final _breakpoint = Breakpoint.fromMediaQuery(context);
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```
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Use `BreakpointBuilder` if you want the layout builder wrapped for you.
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``` dart
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return BreakpointBuilder(
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builder: (context, breakpoint) {
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print('Breakpoint: $breakpoint');
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return Container();
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},
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);
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```
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## Example
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``` dart
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import 'dart:io';
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import 'package:flutter/foundation.dart';
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import 'package:flutter/material.dart';
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import 'package:breakpoint/breakpoint.dart';
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/// main is entry point of Flutter application
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void main() {
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// Desktop platforms aren't a valid platform.
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_setTargetPlatformForDesktop();
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return runApp(MyApp());
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}
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/// If the current platform is desktop, override the default platform to
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/// a supported platform (iOS for macOS, Android for Linux and Windows).
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/// Otherwise, do nothing.
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void _setTargetPlatformForDesktop() {
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TargetPlatform targetPlatform;
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if (Platform.isMacOS) {
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targetPlatform = TargetPlatform.iOS;
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} else if (Platform.isLinux || Platform.isWindows) {
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targetPlatform = TargetPlatform.android;
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}
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if (targetPlatform != null) {
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debugDefaultTargetPlatformOverride = targetPlatform;
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}
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}
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class MyApp extends StatelessWidget {
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@override
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Widget build(BuildContext context) {
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return MaterialApp(
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title: 'Flutter Demo',
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theme: ThemeData(
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primarySwatch: Colors.blue,
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),
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home: MyHomePage(),
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);
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}
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}
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class MyHomePage extends StatelessWidget {
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@override
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Widget build(BuildContext context) {
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return LayoutBuilder(builder: (_, constraints) {
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final _breakpoint = Breakpoint.fromConstraints(constraints);
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return Scaffold(
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appBar: AppBar(
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title: Text('Breakpoint Example: ${_breakpoint.toString()}'),
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),
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body: Container(
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padding: EdgeInsets.all(_breakpoint.gutters),
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child: GridView.builder(
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gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
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crossAxisCount: _breakpoint.columns,
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crossAxisSpacing: _breakpoint.gutters,
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mainAxisSpacing: _breakpoint.gutters,
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),
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itemCount: 200,
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itemBuilder: (_, index) {
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return Container(
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child: Card(
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child: Text(
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index.toString(),
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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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}
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```
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