flutter-quill/doc/custom_toolbar.md

Custom Toolbar

If you want to use custom toolbar but still want the support of this libray You can use the QuillBaseToolbar which is the base for the QuillToolbar

If you are using the toolbar buttons like QuillToolbarHistoryButton, QuillToolbarToggleStyleButton in the somewhere like the the custom toolbar then you must provide them with QuillToolbarProvider inherited widget, you don't have to do this if you are using the QuillToolbar since it will be done for you

Example:

QuillProvider(
  configurations: QuillConfigurations(
    controller: _controller,
    sharedConfigurations: const QuillSharedConfigurations(),
  ),
  child: Column(
    children: [
      QuillToolbarProvider(
        toolbarConfigurations: const QuillToolbarConfigurations(),
        child: QuillBaseToolbar(
          configurations: QuillBaseToolbarConfigurations(
            toolbarSize: 15 * 2,
            multiRowsDisplay: false,
            childrenBuilder: (context) {
              final controller = context.requireQuillController;
              return [
                QuillToolbarHistoryButton(
                  controller: controller,
                  options: const QuillToolbarHistoryButtonOptions(
                      isUndo: true),
                ),
                QuillToolbarHistoryButton(
                  controller: controller,
                  options: const QuillToolbarHistoryButtonOptions(
                      isUndo: false),
                ),
                QuillToolbarToggleStyleButton(
                  attribute: Attribute.bold,
                  controller: controller,
                  options: const QuillToolbarToggleStyleButtonOptions(
                    iconData: Icons.format_bold,
                    iconSize: 20,
                  ),
                ),
                QuillToolbarToggleStyleButton(
                  attribute: Attribute.italic,
                  controller: controller,
                  options: const QuillToolbarToggleStyleButtonOptions(
                    iconData: Icons.format_italic,
                    iconSize: 20,
                  ),
                ),
                QuillToolbarToggleStyleButton(
                  attribute: Attribute.underline,
                  controller: controller,
                  options: const QuillToolbarToggleStyleButtonOptions(
                    iconData: Icons.format_underline,
                    iconSize: 20,
                  ),
                ),
                QuillToolbarClearFormatButton(
                  controller: controller,
                  options: const QuillToolbarClearFormatButtonOptions(
                    iconData: Icons.format_clear,
                    iconSize: 20,
                  ),
                ),
                VerticalDivider(
                  indent: 12,
                  endIndent: 12,
                  color: Colors.grey.shade400,
                ),
                QuillToolbarSelectHeaderStyleButtons(
                  controller: controller,
                  options:
                      const QuillToolbarSelectHeaderStyleButtonsOptions(
                    iconSize: 20,
                  ),
                ),
                QuillToolbarToggleStyleButton(
                  attribute: Attribute.ol,
                  controller: controller,
                  options: const QuillToolbarToggleStyleButtonOptions(
                    iconData: Icons.format_list_numbered,
                    iconSize: 20,
                  ),
                ),
                QuillToolbarToggleStyleButton(
                  attribute: Attribute.ul,
                  controller: controller,
                  options: const QuillToolbarToggleStyleButtonOptions(
                    iconData: Icons.format_list_bulleted,
                    iconSize: 20,
                  ),
                ),
                QuillToolbarToggleStyleButton(
                  attribute: Attribute.blockQuote,
                  controller: controller,
                  options: const QuillToolbarToggleStyleButtonOptions(
                    iconData: Icons.format_quote,
                    iconSize: 20,
                  ),
                ),
                VerticalDivider(
                  indent: 12,
                  endIndent: 12,
                  color: Colors.grey.shade400,
                ),
                QuillToolbarIndentButton(
                    controller: controller,
                    isIncrease: true,
                    options: const QuillToolbarIndentButtonOptions(
                      iconData: Icons.format_indent_increase,
                      iconSize: 20,
                    )),
                QuillToolbarIndentButton(
                  controller: controller,
                  isIncrease: false,
                  options: const QuillToolbarIndentButtonOptions(
                    iconData: Icons.format_indent_decrease,
                    iconSize: 20,
                  ),
                ),
              ];
            },
          ),
        ),
      ),
      Expanded(
        child: QuillEditor.basic(
          configurations: const QuillEditorConfigurations(
            readOnly: false,
            placeholder: 'Write your notes',
            padding: EdgeInsets.all(16),
          ),
        ),
      )
    ],
  ),
)

if you want more customized toolbar feel free to create your own and use the controller to interact with the editor. checkout the QuillToolbar and the buttons inside it to see an example of how that will works