flutter/dev/integration_tests/flutter_gallery/lib/gallery/example_code.dart

// 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.

// This code is not runnable, it contains code snippets displayed in the Gallery.

import 'package:flutter/material.dart';

class ButtonsDemo {
  void setState(VoidCallback callback) {}
  late BuildContext context;

  void buttons() {
    // START buttons_elevated
    // Create an elevated button.
    ElevatedButton(
      child: const Text('BUTTON TITLE'),
      onPressed: () {
        // Perform some action
      },
    );

    // Create a disabled button.
    // Buttons are disabled when onPressed isn't
    // specified or is null.
    const ElevatedButton(onPressed: null, child: Text('BUTTON TITLE'));

    // Create a button with an icon and a
    // title.
    ElevatedButton.icon(
      icon: const Icon(Icons.add, size: 18.0),
      label: const Text('BUTTON TITLE'),
      onPressed: () {
        // Perform some action
      },
    );
    // END

    // START buttons_outlined
    // Create an outlined button.
    OutlinedButton(
      child: const Text('BUTTON TITLE'),
      onPressed: () {
        // Perform some action
      },
    );

    // Create a disabled button.
    // Buttons are disabled when onPressed isn't
    // specified or is null.
    const OutlinedButton(onPressed: null, child: Text('BUTTON TITLE'));

    // Create a button with an icon and a
    // title.
    OutlinedButton.icon(
      icon: const Icon(Icons.add, size: 18.0),
      label: const Text('BUTTON TITLE'),
      onPressed: () {
        // Perform some action
      },
    );
    // END

    // START buttons_text
    // Create a text button.
    TextButton(
      child: const Text('BUTTON TITLE'),
      onPressed: () {
        // Perform some action
      },
    );

    // Create a disabled button.
    // Buttons are disabled when onPressed isn't
    // specified or is null.
    const TextButton(onPressed: null, child: Text('BUTTON TITLE'));
    // END

    // START buttons_dropdown
    // Member variable holding value.
    String? dropdownValue;

    // Dropdown button with string values.
    DropdownButton<String>(
      value: dropdownValue,
      onChanged: (String? newValue) {
        // null indicates the user didn't select a
        // new value.
        setState(() {
          if (newValue != null) {
            dropdownValue = newValue;
          }
        });
      },
      items:
          <String>['One', 'Two', 'Free', 'Four'].map<DropdownMenuItem<String>>((String value) {
            return DropdownMenuItem<String>(value: value, child: Text(value));
          }).toList(),
    );
    // END

    // START buttons_icon
    // Member variable holding toggle value.
    late bool value = true;

    // Toggleable icon button.
    IconButton(
      icon: const Icon(Icons.thumb_up),
      onPressed: () {
        setState(() => value = !value);
      },
      color: value ? Theme.of(context).primaryColor : null,
    );
    // END

    // START buttons_action
    // Floating action button in Scaffold.
    Scaffold(
      appBar: AppBar(title: const Text('Demo')),
      floatingActionButton: const FloatingActionButton(onPressed: null, child: Icon(Icons.add)),
    );
    // END
  }
}

class SelectionControls {
  void setState(VoidCallback callback) {}

  void selectionControls() {
    // START selectioncontrols_checkbox
    // Member variable holding the checkbox's value.
    bool? checkboxValue = false;

    // Create a checkbox.
    Checkbox(
      value: checkboxValue,
      onChanged: (bool? value) {
        setState(() {
          checkboxValue = value;
        });
      },
    );

    // Create a tristate checkbox.
    Checkbox(
      tristate: true,
      value: checkboxValue,
      onChanged: (bool? value) {
        setState(() {
          checkboxValue = value;
        });
      },
    );

    // Create a disabled checkbox.
    // Checkboxes are disabled when onChanged isn't
    // specified or null.
    const Checkbox(value: false, onChanged: null);
    // END

    // START selectioncontrols_radio
    // Member variable holding value.
    int? radioValue = 0;

    // Method setting value.
    void handleRadioValueChanged(int? value) {
      setState(() {
        radioValue = value;
      });
    }

    // Creates a set of radio buttons.
    Row(
      children: <Widget>[
        Radio<int>(value: 0, groupValue: radioValue, onChanged: handleRadioValueChanged),
        Radio<int>(value: 1, groupValue: radioValue, onChanged: handleRadioValueChanged),
        Radio<int>(value: 2, groupValue: radioValue, onChanged: handleRadioValueChanged),
      ],
    );

    // Creates a disabled radio button.
    const Radio<int>(value: 0, groupValue: 0);
    // END

    // START selectioncontrols_switch
    // Member variable holding value.
    bool switchValue = false;

    // Create a switch.
    Switch(
      value: switchValue,
      onChanged: (bool value) {
        setState(() {
          switchValue = value;
        });
      },
    );

    // Create a disabled switch.
    // Switches are disabled when onChanged isn't
    // specified or null.
    const Switch(value: false, onChanged: null);
    // END
  }
}

class GridLists {
  void gridlists() {
    // START gridlists
    // Creates a scrollable grid list with images
    // loaded from the web.
    GridView.count(
      crossAxisCount: 3,
      padding: const EdgeInsets.all(4.0),
      mainAxisSpacing: 4.0,
      crossAxisSpacing: 4.0,
      children:
          <String>[
            'https://example.com/image-0.jpg',
            'https://example.com/image-1.jpg',
            'https://example.com/image-2.jpg',
            '...',
            'https://example.com/image-n.jpg',
          ].map<Widget>((String url) {
            return GridTile(
              footer: GridTileBar(title: Text(url)),
              child: Image.network(url, fit: BoxFit.cover),
            );
          }).toList(),
    );
    // END
  }
}

class AnimatedImage {
  void animatedImage() {
    // START animated_image
    Image.network('https://example.com/animated-image.gif');
    // END
  }
}