Flutter Range Slider Beautiful Customization With Example | Syncfusion

flutter range slider syncfusion

In this Flutter tutorial, we’ll learn the concept of the Flutter range slider in detail. We’ll understand the Flutter syncfusion single slider and range slider with the help of multiple detailed Flutter code examples. So without any more delay, let’s jump right into its implementation.

What is Flutter Range Slider?

Flutter Sliders is a very beautiful and user-friendly way of getting data from users. Users just have to slide the slider to specify the particular value.

If the slider is a range slider, then the user can specify the first and last slider. For example, if some specific range of age is required then the user can slide the first point and the second point of the slider to specify the starting and ending range. So, in this way, all the age group that lies within that range will be taken. You can use it according to your project requirements.

Import Syncfusion Flutter Sliders

syncfusion_flutter_sliders: ^19.4.55

Write this line in the dependencies section of your pubspec.yaml and run pub get to import the package in your app.
To get the latest version of this package, visit here.
flutter suncfusion sliders package

Flutter Syncfusion Sliders (Single Slider and Range Slider)

The two sliders are listed below:

  • Flutter Syncfusion Range Slider
  • Flutter Syncfusion Single Slider

We will explain the range slider in this article and would love to see you practice the single slider. Don’t worry, it will be implemented in the source code examples as well, so if you feel stuck then you can check it out in the source code that will be provided. Let’s now implement our syncfusion range slider in our app.

Syncfusion Range Slider


                  min: 0,

                  max: 100,

                  values: SfRangeValues(0, 100),

                  onChanged: (value) {},

simple range slider
We have used the sf range slider class, in which:
  • The min constructor defines the minimum amount that the user can select.
  • The max constructor defines the max amount that the user can select.
  • The values constructor defines the currently selected values in the slider using the thumbs(these two small circles in the slider).
  • On changed constructor is called when the user drags one of the thumbs to select a new value.

As you can see, by implementing this code, we now see a blue slider on our screen, having two thumbs that are not yet slidable, to make them slidable, we have to give dynamic values to our values constructor using the onChanged constructor.

Dynamic Values In Range Slider

                  min: 0,
                  max: 100,
                  values: SfRangeValues(rangeStart, rangeEnd),
                  onChanged: (value) {
                    setState(() {
                      rangeStart = value.start;
                      rangeEnd = value.end;
We have defined two double values of names range start and range end and have given the range start a value of 0 and range end a value of 100. We now have used them in our values constructor using the sf range values class which takes two arguments, the first one is the starting range and the second one is the ending range.

Now we want to specify the values dynamically in our two variables so we have used them within the onChanged constructor and by using the argument that the onChanged function has. We can take the value of the start and end from that argument and have given it to our range start and range end.

To see this value changes in real-time, we have used the set state which rebuilds or updates the state every time it is called.

Tool Tip Of Range Slider

enableTooltip: true
simple range slider tooltip
The enableTooltip constructor specifies whether the tooltip should be shown or not in the slider. By default, it is false, making it true will show the tooltip when the drag occurs.
Tool Tip Customization
                  data: SfRangeSliderThemeData(
                    tooltipBackgroundColor: Colors.white,
                    tooltipTextStyle: TextStyle(
                        color: Color(0xffF5B7B1),
                        fontSize: 12,
                        fontWeight: FontWeight.w600),
                 child: SfRangeSlider(
                         // the slider that we are currently working on

As you can see, we have wrapped our sf range slider with an sf range slider theme class. By using its data constructor, we can customize the theme data of our sf range slider.

  • The tooltip background color constructor is used to change the background color of our tooltip, we have specified it to white.
  • Tooltip text style constructor is used to style text that appears in the tooltip. By using it, we have customized the text color, size, and weight. You can specify different values depending on the design that you want to get.
  • import ‘package:syncfusion_flutter_core/theme.dart’; Import the theme in case you don’t see it in the suggestions.

Let’s see how our tooltip looks now when we drag our slider:

simple range slider customized tooltip


Tool Tip Text Formatter Callback
tooltipTextFormatterCallback: (actualValue, formattedText) {

                      double d = actualValue;

                      return '${d.toStringAsFixed(0)} years old';


The tooltip text formatter callback constructor is used to format or change the label text of the tooltip.

  • The value that is given without proper formatting is in the actual value parameter. It can be a double or a date time etc.
  • The formatted text parameter stores the proper format based on the value i.e. double of date time etc.

Now when you slide the thumbs of the slider, you will see an update in the values of both thumb tooltips. The reason is that we have returned a string having the actual value and have specified the toStringAsFixed function to zero means there will be no numbers after the period(.). For instance, 2.54 will become 2.

Drag Mode

dragMode: SliderDragMode.both
Using the drag mode constructor of the sf range slider class, we can specify whether we want to do the dragging action by dragging the thumb or the slider path, or both.
  • dragMode: SliderDragMode.onThumb                      Drag using thumb
  • dragMode: SliderDragMode.betweenThumbs          Drag using the slider path between the two thumbs
  • dragMode: SliderDragMode.both                                 Drag using both, either we can use thumb or the sliding path

Active Color

activeColor: Color(0xffF5B7B1)
colored range slider
Using the active color constructor of the sf range slider, we can change the color of the active region of the slider. We can see in the example that the active slider and color of both thumbs are now changed.

Start Thumb Icon

 startThumbIcon: Container(
                      decoration: BoxDecoration(
                          color: Colors.white, shape: BoxShape.circle),
                      child: Container(
                        decoration: BoxDecoration(
                            color: Color(0xffF5B7B1), shape: BoxShape.circle),
                        margin: EdgeInsets.all(3),
colored range slider start thumb customized
By using the start thumb icon constructor, we can customize our start thumb. For demonstration, we have used a container widget in it. We have customized our container and given it a margin so it will have some margin from the pre-defined thumb icon shape. You can see the customized start thumb in the above image.

End thumb Icon

 endThumbIcon: Container(
                      decoration: BoxDecoration(
                          color: Colors.white, shape: BoxShape.circle),
                      child: Container(
                        decoration: BoxDecoration(
                            color: Color(0xffF5B7B1), shape: BoxShape.circle),
                        margin: EdgeInsets.all(3),
colored range slider start and end thumb customized
The same customization is done for the end thumb as well. We use the end thumb icon constructor to customize the end thumb. You can use different customizations for them as well. We can see that our both thumbs are now customized.

Show Always Tool Tip

shouldAlwaysShowTooltip: true
Using the should always show tooltip constructor will make the tooltip visible even if you are not dragging the thumbs or slider.

Congrats, we now have achieved our mentioned design. Below is the complete source code in which implementation for both Flutter single and range sliders are specified.

Beautiful flutter range slider and simple slider


Hope you now have detailed practical knowledge of how to implement a Flutter range slider as well as a single slider. Do feel free to deliver your valuable feedback using the comment section.

We’d also be glad to see you visit our other tutorials on Flutter app development and Python programming. Thank you for reading this one.

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