draggable_scrollbar

A scrollbar that can be used to quickly navigate through a list. Please note: This isn't my work! It was created by Marica, and I've made a few small updates.

Usage

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

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

Google Photos Handle

DraggableScrollbar.googlePhotos(
  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 handle + 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 Handle

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()),
          ),
        ),
      );
    },
  ),
  heightScrollHandle: 48.0,
  backgroundColor: Colors.blue,
  scrollHandleBuilder: (
    Color backgroundColor,
    Animation<double> handleAnimation,
    Animation<double> labelAnimation,
    double height, {
    Text labelText,
  }) {
    return FadeTransition(
      opacity: handleAnimation,
      child: Container(
        height: height,
        width: 20.0,
        color: backgroundColor,
      ),
    );
  },
);