Getting started with Flutter Slider (Slider)

27 Jan 202320 minutes to read

This section explains the steps required to add the slider widget and its elements such as numeric and date values, ticks, labels and tooltip. This section covers only basic features needed to know to get started with Syncfusion slider.

To get start quickly with our Flutter Slider widget, you can check on this video.

Add Flutter slider to an application

Create a simple project using the instructions given in the Getting Started with your first Flutter app documentation.

Add dependency

Add the Syncfusion Flutter slider dependency to your pubspec.yaml file.

DART

dependencies:

syncfusion_flutter_sliders: ^xx.x.xx

NOTE

Here xx.x.xx denotes the current version of Syncfusion Flutter Sliders package.

Get packages

Run the following command to get the required packages.

DART

$ flutter pub get

Import package

Import the following package in your Dart code.

DART

import 'package:syncfusion_flutter_sliders/sliders.dart';

Initialize slider

After importing the package, initialize the slider widget as a child of any widget. Here, the slider widget is added as a child of the Center widget. The default value of the min and max properties of the SfSlider is 0.0 and 1.0 respectively. So, the value property must be given within the range.

NOTE

The slider passes the new value to the onChanged callback but does not change its state until the parent widget rebuilds the slider with new value.

Horizontal

DART

double _value = 0.5;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider(
        value: _value,
        onChanged: (dynamic newValue){
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Vertical

DART

double _value = 0.5;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider.vertical(
        value: _value,
        onChanged: (dynamic newValue){
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Handle value change

The onChanged callback is used to get the current value of the slider when the user selects a value through interaction.

NOTE

The slider passes the new value to the callback but does not change its state until the parent widget rebuilds the slider with new value.

Horizontal

DART

double _value = 5.0;

@override
Widget build(BuildContext context) {
  return MaterialApp(
      home: Scaffold(
          body: Center(
              child: SfSlider(
                min: 0.0,
                max: 10.0,
                value: _value,
                onChanged: (dynamic newValue) {
                  setState(() {
                    _value = newValue;
                  });
                },
              )
          )
      )
  );
}

Vertical

DART

double _value = 5.0;

@override
Widget build(BuildContext context) {
  return MaterialApp(
      home: Scaffold(
          body: Center(
              child: SfSlider.vertical(
                min: 0.0,
                max: 10.0,
                value: _value,
                onChanged: (dynamic newValue) {
                  setState(() {
                    _value = newValue;
                  });
                },
              )
          )
      )
  );
}

Set numeric value

You can show numeric values in the slider by setting double values to the min, max and value properties.

Horizontal

DART

final double _min = 0;
final double _max = 100;
double _value = 40.0;

@override
Widget build(BuildContext context) {
  return MaterialApp(
      home: Scaffold(
          body: Center(
            child: SfSlider(
              min: _min,
              max: _max,
              value: _value,
              interval: 20,
              showLabels: true,
              onChanged: (dynamic newValue) {
                setState(() {
                  _value = newValue;
                });
              },
            ),
          )
      )
  );
}

Vertical

DART

final double _min = 0;
final double _max = 100;
double _value = 40.0;

@override
Widget build(BuildContext context) {
  return MaterialApp(
      home: Scaffold(
          body: Center(
            child: SfSlider.vertical(
              min: _min,
              max: _max,
              value: _value,
              interval: 20,
              showLabels: true,
              onChanged: (dynamic newValue) {
                setState(() {
                  _value = newValue;
                });
              },
            ),
          )
      )
  );
}

Set date value

You can show date values in the slider by setting DateTime values to the min, max and value properties.

NOTE

You must import intl package for formatting date slider using the DateFormat class.

Horizontal

DART

DateTime _min = DateTime(2008, 01, 01);
DateTime _max = DateTime(2018, 01, 01);
DateTime _value = DateTime(2012, 01, 01);

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider(
        min: _min,
        max: _max,
        value: _value,
        interval: 2,
        showLabels: true,
        dateIntervalType: DateIntervalType.years,
        dateFormat: DateFormat.y(),
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Vertical

DART

DateTime _min = DateTime(2008, 01, 01);
DateTime _max = DateTime(2018, 01, 01);
DateTime _value = DateTime(2012, 01, 01);

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider.vertical(
        min: _min,
        max: _max,
        value: _value,
        interval: 2,
        showLabels: true,
        dateIntervalType: DateIntervalType.years,
        dateFormat: DateFormat.y(),
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Enable ticks

You can enable ticks in the slider using the showTicks property.

Horizontal

DART

final double _min = 0;
final double _max = 100;
double _value = 40.0;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider(
        min: _min,
        max: _max,
        value: _value,
        interval: 20,
        showTicks: true,
        showLabels: true,
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Vertical

DART

final double _min = 0;
final double _max = 100;
double _value = 40.0;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider.vertical(
        min: _min,
        max: _max,
        value: _value,
        interval: 20,
        showTicks: true,
        showLabels: true,
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Inverse the horizontal slider

You can invert the horizontal slider by wrapping the slider to the Directionality widget by setting textDirection property to TextDirection.rtl.

DART

double _value = 40.0;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Directionality(
      textDirection: TextDirection.rtl,
      child: SfSlider(
        min: 0,
        max: 100,
        value: _value,
        interval: 20,
        showTicks: true,
        showLabels: true,
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Inverse the vertical slider

You can invert the vertical slider using the isInversed property. The default value of the isInversed property is false.

DART

double _value = 40.0;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: SfSlider.vertical(
      min: 0,
      max: 100,
      value: _value,
      interval: 20,
      isInversed: true,
      showTicks: true,
      showLabels: true,
      onChanged: (dynamic newValue) {
        setState(() {
          _value = newValue;
        });
      },
    ),
  );
}

Add prefix/suffix to labels

You can add prefix or suffix to the labels using the numberFormat or dateFormat properties.

NOTE

The format type (numeric or date) of the slider is determined based on the values specified in min, max and value properties.

IMPORTANT

You must import intl package for formatting date slider using the DateFormat class and for formatting numeric slider using the NumberFormat class.

Horizontal

DART

final double _min = 0;
final double _max = 100;
double _value = 40.0;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider(
        min: _min,
        max: _max,
        value: _value,
        interval: 20,
        showTicks: true,
        showLabels: true,
        numberFormat: NumberFormat("\$"),
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}

Vertical

DART

final double _min = 0;
final double _max = 100;
double _value = 40.0;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: SfSlider.vertical(
        min: _min,
        max: _max,
        value: _value,
        interval: 20,
        showTicks: true,
        showLabels: true,
        numberFormat: NumberFormat("\$"),
        onChanged: (dynamic newValue) {
          setState(() {
            _value = newValue;
          });
        },
      ),
    ),
  );
}