snack_bar.2.dart 5.51 KB
Newer Older
1 2 3 4 5 6
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';

7
/// Flutter code sample for [SnackBar].
8 9

void main() => runApp(const SnackBarExampleApp());
10

11 12
/// A Material 3 [SnackBar] demonstrating an optional icon, in either floating
/// or fixed format.
13 14
class SnackBarExampleApp extends StatelessWidget {
  const SnackBarExampleApp({super.key});
15 16 17 18 19 20

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: Scaffold(
21
        appBar: AppBar(title: const Text('SnackBar Sample')),
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
        body: const Center(
          child: SnackBarExample(),
        ),
      ),
    );
  }
}

class SnackBarExample extends StatefulWidget {
  const SnackBarExample({super.key});

  @override
  State<SnackBarExample> createState() => _SnackBarExampleState();
}

class _SnackBarExampleState extends State<SnackBarExample> {
  SnackBarBehavior? _snackBarBehavior = SnackBarBehavior.floating;
  bool _withIcon = true;
  bool _withAction = true;
  bool _multiLine = false;
  bool _longActionLabel = false;
43
  double _sliderValue = 0.25;
44

45
  Padding _padRow(List<Widget> children) => Padding(
46 47 48
        padding: const EdgeInsets.all(8.0),
        child: Row(children: children),
      );
49 50 51

  @override
  Widget build(BuildContext context) {
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136
    return Padding(
      padding: const EdgeInsets.only(left: 50.0),
      child: Column(
        children: <Widget>[
          _padRow(<Widget>[
            Text('Snack Bar configuration', style: Theme.of(context).textTheme.bodyLarge),
          ]),
          _padRow(
            <Widget>[
              const Text('Fixed'),
              Radio<SnackBarBehavior>(
                value: SnackBarBehavior.fixed,
                groupValue: _snackBarBehavior,
                onChanged: (SnackBarBehavior? value) {
                  setState(() {
                    _snackBarBehavior = value;
                  });
                },
              ),
              const Text('Floating'),
              Radio<SnackBarBehavior>(
                value: SnackBarBehavior.floating,
                groupValue: _snackBarBehavior,
                onChanged: (SnackBarBehavior? value) {
                  setState(() {
                    _snackBarBehavior = value;
                  });
                },
              ),
            ],
          ),
          _padRow(
            <Widget>[
              const Text('Include Icon '),
              Switch(
                value: _withIcon,
                onChanged: (bool value) {
                  setState(() {
                    _withIcon = !_withIcon;
                  });
                },
              ),
            ],
          ),
          _padRow(
            <Widget>[
              const Text('Include Action '),
              Switch(
                value: _withAction,
                onChanged: (bool value) {
                  setState(() {
                    _withAction = !_withAction;
                  });
                },
              ),
              const SizedBox(width: 16.0),
              const Text('Long Action Label '),
              Switch(
                value: _longActionLabel,
                onChanged: !_withAction
                    ? null
                    : (bool value) {
                        setState(() {
                          _longActionLabel = !_longActionLabel;
                        });
                      },
              ),
            ],
          ),
          _padRow(
            <Widget>[
              const Text('Multi Line Text'),
              Switch(
                value: _multiLine,
                onChanged: _snackBarBehavior == SnackBarBehavior.fixed
                    ? null
                    : (bool value) {
                        setState(() {
                          _multiLine = !_multiLine;
                        });
                      },
              ),
            ],
          ),
          _padRow(<Widget>[
137 138 139 140 141
            const Text('Action new-line overflow threshold'),
            Slider(
              value: _sliderValue,
              divisions: 20,
              label: _sliderValue.toStringAsFixed(2),
142 143 144 145 146 147 148
              onChanged: _snackBarBehavior == SnackBarBehavior.fixed
                  ? null
                  : (double value) {
                      setState(() {
                        _sliderValue = value;
                      });
                    },
149
            ),
150 151 152 153 154 155 156 157 158 159 160 161
          ]),
          const SizedBox(height: 16.0),
          ElevatedButton(
            child: const Text('Show Snackbar'),
            onPressed: () {
              ScaffoldMessenger.of(context).showSnackBar(_snackBar());
            },
          ),
        ],
      ),
    );
  }
162 163 164 165 166 167 168 169 170 171

  SnackBar _snackBar() {
    final SnackBarAction? action = _withAction
        ? SnackBarAction(
            label: _longActionLabel ? 'Long Action Text' : 'Action',
            onPressed: () {
              // Code to execute.
            },
          )
        : null;
172 173 174
    final double? width = _snackBarBehavior == SnackBarBehavior.floating && _multiLine ? 400.0 : null;
    final String label =
        _multiLine ? 'A Snack Bar with quite a lot of text which spans across multiple lines' : 'Single Line Snack Bar';
175 176 177 178 179 180 181
    return SnackBar(
      content: Text(label),
      showCloseIcon: _withIcon,
      width: width,
      behavior: _snackBarBehavior,
      action: action,
      duration: const Duration(seconds: 3),
182
      actionOverflowThreshold: _sliderValue,
183 184 185
    );
  }
}