Draggable Scrollbar

Pub

A scrollbar that can be dragged for quickly navigation through a vertical list. Additionaly it can show label next to scrollthumb with information about current item, for example date of picture created

Usage

You can use one of the three built-in scroll thumbs, or you can create a custom thumb for your own app!

You can play with all of these examples by running the app found in the example folder.

Example

Semicircle Thumb

DraggableScrollbar.semicircle(
  controller: myScrollController,
  child: GridView.builder(
    gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
      crossAxisCount: 5,
    ),
    controller: myScrollController,
    padding: EdgeInsets.zero,
    itemCount: 1000,
    itemBuilder: (context, index) {
      return Container(
        alignment: Alignment.center,
        margin: EdgeInsets.all(2.0),
        color: Colors.grey[300],
      );
    },
  ),
);

Arrows thumb + label

DraggableScrollbar.arrows(
  labelTextBuilder: (double offset) => Text("${offset ~/ 100}"),
  controller: myScrollController,
  child: ListView.builder(
    controller: myScrollController,
    itemCount: 1000,
    itemExtent: 100.0,
    itemBuilder: (context, index) {
      return Container(
        padding: EdgeInsets.all(8.0),
        child: Material(
          elevation: 4.0,
          borderRadius: BorderRadius.circular(4.0),
          color: Colors.purple[index % 9 * 100],
          child: Center(
            child: Text(index.toString()),
          ),
        ),
      );
    },
  ),
);

Rounded Rectangle Thumb

DraggableScrollbar.rrect(
  controller: myScrollController,
  child: ListView.builder(
    controller: myScrollController,
    itemCount: 1000,
    itemExtent: 100.0,
    itemBuilder: (context, index) {
      return Container(
        padding: EdgeInsets.all(8.0),
        child: Material(
          elevation: 4.0,
          borderRadius: BorderRadius.circular(4.0),
          color: Colors.green[index % 9 * 100],
          child: Center(
            child: Text(index.toString()),
          ),
        ),
      );
    },
  ),
);

Custom

DraggableScrollbar(
  controller: myScrollController,
  child: ListView.builder(
    controller: myScrollController,
    itemCount: 1000,
    itemExtent: 100.0,
    itemBuilder: (context, index) {
      return Container(
        padding: EdgeInsets.all(8.0),
        child: Material(
          elevation: 4.0,
          borderRadius: BorderRadius.circular(4.0),
          color: Colors.cyan[index % 9 * 100],
          child: Center(
            child: Text(index.toString()),
          ),
        ),
      );
    },
  ),
  heightScrollThumb: 48.0,
  backgroundColor: Colors.blue,
  scrollThumbBuilder: (
    Color backgroundColor,
    Animation<double> thumbAnimation,
    Animation<double> labelAnimation,
    double height, {
    Text labelText,
  }) {
    return FadeTransition(
      opacity: thumbAnimation,
      child: Container(
        height: height,
        width: 20.0,
        color: backgroundColor,
      ),
    );
  },
);

Libraries

draggable_scrollbar

Dart

dart:ui
Built-in types and core primitives for a Flutter application. [...]

Core

dart:async
Support for asynchronous programming, with classes such as Future and Stream. [...]
dart:collection
Classes and utilities that supplement the collection support in dart:core. [...]
dart:convert
Encoders and decoders for converting between different data representations, including JSON and UTF-8. [...]
dart:core
Built-in types, collections, and other core functionality for every Dart program. [...]
dart:developer
Interact with developer tools such as the debugger and inspector. [...]
dart:math
Mathematical constants and functions, plus a random number generator. [...]
dart:typed_data
Lists that efficiently handle fixed sized data (for example, unsigned 8 byte integers) and SIMD numeric types. [...]

VM

dart:io
File, socket, HTTP, and other I/O support for non-web applications. [...]
dart:isolate
Concurrent programming using isolates: independent workers that are similar to threads but don't share memory, communicating only via messages. [...]