Tuesday, March 19, 2024

Material design slider and range slider in Flutter

Flutter Slider is a versatile widget that allows you to create both single-value and range sliders in a variety of styles and orientations, all designed to conform to Google’s Material Design guidelines.

With support for right-to-left languages and a wide range of customization options, this widget is perfect for building polished, responsive user interfaces in your Flutter app. Whether you need a simple horizontal slider or a complex range slider with custom labels and icons, Flutter Slider has you covered.

Get Started

Single Slider

A single slider

FlutterSlider(
  values: [300],
  max: 500,
  min: 0,
  onDragging: (handlerIndex, lowerValue, upperValue) {
    _lowerValue = lowerValue;
    _upperValue = upperValue;
    setState(() {});
  },
)

To make slider Right To Left use rtl: true

 FlutterSlider(
  ...
  rtl: true,
  ...
)

Range Slider

A simple example of range slider

FlutterSlider(
  values: [30, 420],
  rangeSlider: true,
  max: 500,
  min: 0,
  onDragging: (handlerIndex, lowerValue, upperValue) {
    _lowerValue = lowerValue;
    _upperValue = upperValue;
    setState(() {});
  },
)

Vertical Axis

You can change the axis of your slider by setting axis to Axis.vertical. Default is horizontal

FlutterSlider(
  ...
  axis: Axis.vertical,
  ...
)

Handlers

You can customize handlers using handler and rightHandler properties.
Both handler and rightHandler accept FlutterSliderHandler class which has following properties:

  1. child: is a widget
  2. disabled: to disable the handler
  3. decorationforegroundDecoration and transform are come from Container() widget
FlutterSlider(
  ...
  handler: FlutterSliderHandler(
    decoration: BoxDecoration(),
    child: Material(
      type: MaterialType.canvas,
      color: Colors.orange,
      elevation: 3,
      child: Container(
          padding: EdgeInsets.all(5),
          child: Icon(Icons.adjust, size: 25,)),
    ),
  ),
  rightHandler: FlutterSliderHandler(
    child: Icon(Icons.chevron_left, color: Colors.red, size: 24,),
  ),
  ...
)

Handler Scale Animation

You can control the scale animation type of your handlers, it’s duration and it’s scale size using handlerAnimation
handlerAnimation accepts a FlutterSliderHandlerAnimation class which has 4 properties as following

FlutterSlider(
  ...
    handlerAnimation: FlutterSliderHandlerAnimation(
      curve: Curves.elasticOut,
      reverseCurve: Curves.bounceIn,
      duration: Duration(milliseconds: 500),
      scale: 1.5
    ),
  ...
)

if you don’t want scale animation, then just pass 1 to scale property
if you don’t want reverseCurve, just ignore it. default is null

Trackbars

To customize track bars you can use FlutterSliderTrackBarYou can see the details here

FlutterSlider(
  ...
    trackBar: FlutterSliderTrackBar(
      activeTrackBarHeight: 5,
    ),
  ...
)

inactiveTrackBarColor and activeTrackBarColor properties are removed. use inactiveTrackBar and activeTrackBar instead.

FlutterSlider(
  ...
    trackBar: FlutterSliderTrackBar(
      inactiveTrackBar: BoxDecoration(
        borderRadius: BorderRadius.circular(20),
        color: Colors.black12,
        border: Border.all(width: 3, color: Colors.blue),
      ),
      activeTrackBar: BoxDecoration(
        borderRadius: BorderRadius.circular(4),
        color: Colors.blue.withOpacity(0.5)
      ),
    ),
  ...
)

Central Widget

If you want to have a widget in the middle of your slider, you can use centralWidget

FlutterSlider(
  ...
    trackBar: FlutterSliderTrackBar(
        centralWidget: Container(
          decoration: BoxDecoration(
              color: trackBarColor,
            borderRadius: BorderRadius.circular(50)
          ),
          width: 9,
          height: 9,
        ),
    ),
  ...
)

Tooltips

In order to customize your tooltips, you can use FlutterSliderTooltip class. You can see all properties here

FlutterSlider(
  ...
  tooltip: FlutterSliderTooltip(
    textStyle: TextStyle(fontSize: 17, color: Colors.white),
    boxStyle: FlutterSliderTooltipBox(
      decoration: BoxDecoration(
        color: Colors.redAccent.withOpacity(0.7)
      )
    )
  ),
  ...
)

Here there is a range slider with customized handlers, trackbars and tooltips

Tooltip Prefix

You can use leftPrefixleftSuffixrightPrefixrightSuffix to add your desired widget around tooltip content.

FlutterSlider(
  ...
    tooltip: FlutterSliderTooltip(
      leftPrefix: Icon(Icons.attach_money, size: 19, color: Colors.black45,),
      rightSuffix: Icon(Icons.attach_money, size: 19, color: Colors.black45,),
    ),
  ...
)

Tooltip Format

If you want to change the format of the value of tooltip you can use format method.

FlutterSlider(
  ...
    tooltip: FlutterSliderTooltip(
      format: (String value) {
        return value + ' ! ';
      }
    ),
  ...
)

Tooltip Callback

If you want to fully change tooltip widget and use your own customized widget, you can use custom function.

FlutterSlider(
  ...
    tooltip: FlutterSliderTooltip(
      custom: (value) {
        return Text(value.toString());
      }
    ),
  ...
)

Disable Tooltip

To disable tooltips, use disabled in FlutterSliderTooltip class

FlutterSlider(
  ...
    tooltip: FlutterSliderTooltip(
      disabled: true,
    ),
  ...
)

Tooltip Direction

To change the direction of the tooltip, you can use direction

FlutterSlider(
  ...
    tooltip: FlutterSliderTooltip(
      direction: FlutterSliderTooltipDirection.right,
    ),
  ...
)

Tooltip Position Offset

By default tooltip alignment is center, but you can modify it’s topleftright and bottom by using positionOffset

FlutterSlider(
  ...
    tooltip: FlutterSliderTooltip(
      positionOffset: FlutterSliderTooltipPositionOffset(
        top: -100
      ),
    ),
  ...
)

Always Show Tooltips

Tooltips always displayed if this property is set to true.

FlutterSlider(
  ...
  tooltip: FlutterSliderTooltip(
    alwaysShowTooltip: true,
  ),
  ...
)

Controls

Handlers width and height

By default both handlers size are 35 width and height, but you can change this by handlerWidth and handlerHeight

FlutterSlider(
  ...
  handlerWidth: 30,
  handlerHeight: 30,
  ...
)

Select By Tap

You can tap on the slider to select it’s value.
if slider is range-slider, then the closest handler to the selected point will move to that point

FlutterSlider(
  ...
  selectByTap: true, // default is true
  ...
)

if you want to move your handlers by touching and moving active TrackBar, you have to set this to false

Jump

By default slider handlers move fluently, if you set jump to true, handlers will jump between intervals

FlutterSlider(
  ...
  jump: true,
  ...
)

Step

The amount the slider changes on movement can be set using step option

FlutterSlider(
  ...
  step: FlutterSliderStep(step: 1),
  ...
)

Range Step

If you want to have a non-linear slider with different steps, simply use rangeStep feature.

FlutterSlider(
  min: 0,
  max: 1000000,
  ...
  step: FlutterSliderStep(
    step: 1, // default
    isPercentRange: true, // ranges are percents, 0% to 20% and so on... . default is true
    rangeList: [
      FlutterSliderRangeStep(from: 0, to: 20, step: 10000),
      FlutterSliderRangeStep(from: 20, to: 100, step: 200000),
    ]
  ),
  ...
)

Ignore Steps

If your configurations requires that some steps are not available, you can use ignoreSteps property.
this property accepts a simple class to define from and to ranges.

FlutterSlider(
  ...
    ignoreSteps: [
      FlutterSliderIgnoreSteps(from: 8000, to: 12000),
      FlutterSliderIgnoreSteps(from: 18000, to: 22000),
    ],
  ...
)

Fixed Values

If you want to have an array of fixed items and slide through it, you can use fixedValues property. use FlutterSliderFixedValue to add your fixed values.
FlutterSliderFixedValue has following properties:

  1. percent: (int) ( between 0..100 inclusive). the position of fixed item
  2. value: (dynamic) the value of fixed item
  • when using fixedValues, values of values property, must be within 0..100
FlutterSlider(
  ...
    values: [ 10, 50 ],
    fixedValues: [
      FlutterSliderFixedValue(percent: 0, value: "1000"),
      FlutterSliderFixedValue(percent: 10, value: "10K"),
      FlutterSliderFixedValue(percent: 50, value: 50000),
      FlutterSliderFixedValue(percent: 80, value: "80M"),
      FlutterSliderFixedValue(percent: 100, value: "100B"),
    ],
  ...
)

using above example, you get (string) 10K as upperValue or lowerValue (depends on handler), when you reach to 10 percent of the slider, you get (int) 50000 when you reach 50 percent of the slider and so on…

when using fixedValuesmin and max are ignored

Minimum Distance

When using range slider, the minimum distance between two handlers can be defined using minimumDistance option

FlutterSlider(
  ...
    minimumDistance: 300,
  ...
)

Maximum Distance

This is the opposite of minimum distance, when using range slider, the maximum distance between two handlers can be defined using maximumDistance option

FlutterSlider(
  ...
    maximumDistance: 300,
  ...
)

Locked Handlers

If you want to lock your handlers by a certain value, you can use lockHandlers and lockDistance properties

FlutterSlider(
  ...
    lockHandlers: true,
    lockDistance: 50,
  ...
)

Hatch Mark

You can display a Hatch Mark underneath or beside of your slider based on axis. In order to display hatch mark you must
use FlutterSliderHatchMark class which has following properties:

  1. linesDistanceFromTrackBar: The distance of lines from slider. can be negative
  2. bigLine: The widget of big lines in hatch mark
  3. smallLine: The widget of small lines in hatch mark
  4. linesAlignment: the direct of lines, right or left which works as top or bottom on horizontal slider
  5. density: The amount of lines per percent. 1 is default. any number less or more than 1 will decrease and increase lines respectively
  6. displayLines: to display lines. by default is false for the sake of optimization
  7. labels: If you want to display some label or text at certain percent in your hatch mark, you can use labels
  8. labelBox: The widget of label box, however, you can define a widget for each label and have it’s own style
  9. labelsDistanceFromTrackBar: The distance of labels from slider. can be negative
  10. disabled: to disabled the whole hatchmark ( hide )

labels alignment is center

Here is an example:

FlutterSlider(
  ...
    hatchMark: FlutterSliderHatchMark(
       density: 0.5, // means 50 lines, from 0 to 100 percent
       labels: [
         FlutterSliderHatchMarkLabel(percent: 0, label: Text('Start')),
         FlutterSliderHatchMarkLabel(percent: 10, label: Text('10,000')),
         FlutterSliderHatchMarkLabel(percent: 50, label: Text('50 %')),
         FlutterSliderHatchMarkLabel(percent: 80, label: Text('80,000')),
         FlutterSliderHatchMarkLabel(percent: 100, label: Text('Finish')),
       ],
     ),
  ...
)

Centered Origin

If you want the value of your slider originates from center of the slider, then you can use centeredOrigin property

FlutterSlider(
  ...
    centeredOrigin: true
  ...
  
  ...
    trackBar: FlutterSliderTrackBar(
      activeTrackBar: BoxDecoration(color: trackBarColor)
    ),
  ...
  
  ...
    onDragging: (handlerIndex, lowerValue, upperValue) {
        if (lowerValue > (max - min) / 2) {
          trackBarColor = Colors.blueAccent;
        } else {
          trackBarColor = Colors.redAccent;
        }
        setState(() {});
    })
  ...
)

Touch Size

You can control how big a handler’s touch area could be. by default touch size is 25 The range is between 5 to 50

FlutterSlider(
  ...
  touchSize: 25,
  ...
)

To see the touchable area for handlers, set visibleTouchArea to true and test your slider

FlutterSlider(
  ...
  visibleTouchArea: true,
  ...
)

Disabled

to disable your slider, you can use disabled.

FlutterSlider(
  ...
  disabled: true,
  ...
)

RTL

makes the slider Right To Left

FlutterSlider(
  ...
  rtl: true,
  ...
)

Events

There are 3 events

onDragStarted: fires when drag starts
onDragCompleted fires when drag ends
onDragging keeps firing when dragging

All three of above functions returns three values.

(int handlerIndex, dynamic lowerValue, dynamic upperValue)

First value is handlerIndex, which determines the handler. 0 is Left Handler and 1 refers to Right Handler

FlutterSlider(
  ...
  onDragging: (handlerIndex, lowerValue, upperValue) {
    _lowerValue = lowerValue;
    _upperValue = upperValue;
    
    if(handlerIndex == 0)
        print(" Left handler ");
    
    setState(() {});
  },
  ...
)

Working with Dates

Working with dates are simple and straightforward. just pass standard unix timestamp as values like so:

FlutterSlider(
  ...
  values: [
    new DateTime(2019,6,1,0,0,0).millisecondsSinceEpoch.toDouble(), // lower date : 2019-06-01
    new DateTime(2019,9,1,0,0,0).millisecondsSinceEpoch.toDouble(), // upper date : 2019-09-01
  ],
  min: new DateTime(2019,1,1,0,0,0).millisecondsSinceEpoch.toDouble(), // start date : 2019-01-01
  max: new DateTime(2020,1,1,0,0,0).millisecondsSinceEpoch.toDouble(), // finish date : 2020-01-01
  step: FlutterSliderStep(step: 86400), // 1 day
  ...

  ...
  tooltip: FlutterSliderTooltip(
    custom: (value) {
      DateTime dtValue = DateTime.fromMillisecondsSinceEpoch(value.toInt());
      String valueInTime = dtValue.year.toString() + '-' + dtValue.month.toString() + '-' + dtValue.day.toString();
      
      return Text( valueInTime );
    }
  )
  ...

)

Showcase

It’s exciting to see what you’ve build using this package.
Open wiki tab, create a page and share your code and image of your slider with us. Thank you

Here are some examples of what you can make using this package:

Alphabet Range
Waves
Dirty Dial
Alone in the Dark