This Flutter package is a customizable slider widget that provides support for more than two thumbs. It provides an easy implementation of a slider with multiple thumbs that represent values in a range from 0 to 1. The slider can be customized with a custom background widget and a custom thumb builder. It is a powerful tool for creating intuitive and interactive user experiences, e.g. if a gradient creator needs to be implemented in a app.

IMPORTANT

The package only supports sliders with more than 2 thumbs. For 2 or less thumbs the native widgets Slider and RangeSlider should be used.

Features

Different use cases can be covered by using the package:

Linear Gradient creator	Overdrag moves other thumbs	Overdrag stops at next thumb

IMPORTANT

Using the Overdrag Move behaviour with a large amount of thumbs might impact the performace of your app. Please use this behaviour it with caution.

Usage

There are two constructors available: MultiThumbSlider which takes initialSliderValues as parameter to create the slider with thumbs at specific values. And MultiThumbSlider.distributed which takes an integer > 2 in the initialThumbAmount parameter.

Please read the API documentation for detailed information how the different parameters work together and how the MultiThumbSliderController can be used in detail.

Example:

 MultiThumbSlider(
    initalSliderValues: [0.0, 0.1, 0.2, 0.9, 1.0],
    valuesChanged: (List<double> values) {
        // Everytime any thumb is dragged a list of all thumb values
        // is passed via valuesChanged.
    },
    // Optional: Overdrag behaviour of the thumbs.
    // Defaults to ThumbOverdragBehaviour.stop
    overdragBehaviour: ThumbOverdragBehaviour.move,
    // Optional: Lock behaviour of the first an last thumb.
    // Defaults to ThumbLockBehaviour.stop
    lockBehaviour: ThumbLockBehaviour.none,
    // Optional: Custom builder function for the thumb
    thumbBuilder: (BuildContext context, int index) => Text("$index"),
    // Optional: Background widget of the slider.
    background: Container(
        height: 10,
        decoration: BoxDecoration(
            color: Colors.red,
        ),
    ),
    // Optional: Height of the Widget. Defaults to 48.
    height: 72,
    // Optional: MultiThumbSliderController can be used to control the slider after build. E.g adding/removing thumbs, get current values, move thumb, etc.
    controller: MultiThumbSliderController()
),

Bugs or Requests

If you encounter any problems feel free to open an issue. If you feel the library is missing a feature, please raise a ticket on GitHub and I hope I find some time to look into it. Pull requests are also welcome.