flutter_range_slider_ns

Description:

flutter range slider ns

Features #
An extension of the Flutter Material Slider to allow selection of a range of values via 2 thumbs
Getting started #
You should ensure that you add the following dependency in your Flutter project.
dependencies:
flutter_range_slider: "^1.5.0"
You should then run flutter packages upgrade or update your packages in IntelliJ.
In your Dart code, to use it:
import 'package:flutter_range_slider/flutter_range_slider.dart' as frs;
Usage #
An example can be found in the example folder. Check it out.
import 'package:flutter/material.dart';
import 'package:flutter_range_slider_ns/flutter_range_slider_ns.dart' as frs;

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'RangeSlider Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: RangeSliderSample(),
);
}
}

class RangeSliderSample extends StatefulWidget {
@override
_RangeSliderSampleState createState() => _RangeSliderSampleState();
}

class _RangeSliderSampleState extends State<RangeSliderSample> {
// List of RangeSliders to use, together with their parameters
List<RangeSliderData> rangeSliders;

double _lowerValue = 20.0;
double _upperValue = 80.0;
double _lowerValueFormatter = 20.0;
double _upperValueFormatter = 20.0;

@override
void initState() {
super.initState();
rangeSliders = _rangeSliderDefinitions();
}

@override
Widget build(BuildContext context) {
return SafeArea(
top: false,
bottom: false,
child: Scaffold(
appBar: AppBar(title: Text('RangeSlider Demo')),
body: Container(
padding: const EdgeInsets.only(top: 50.0, left: 10.0, right: 10.0),
child: Column(
children: <Widget>[]
..add(
//
// Simple example
//
frs.RangeSlider(
min: 0.0,
max: 100.0,
lowerValue: _lowerValue,
upperValue: _upperValue,
divisions: 5,
showValueIndicator: true,
valueIndicatorMaxDecimals: 1,
onChanged: (double newLowerValue, double newUpperValue) {
setState(() {
_lowerValue = newLowerValue;
_upperValue = newUpperValue;
});
},
onChangeStart:
(double startLowerValue, double startUpperValue) {
print(
'Started with values: $startLowerValue and $startUpperValue');
},
onChangeEnd: (double newLowerValue, double newUpperValue) {
print(
'Ended with values: $newLowerValue and $newUpperValue');
},
),
)
// Add some space
..add(
SizedBox(height: 24.0),
)
//
// Add a series of RangeSliders, built as regular Widgets
// each one having some specific customizations
//
..addAll(_buildRangeSliders())

//
// Add a disabled version
//
..add(
frs.RangeSlider(
min: 0.0,
max: 100.0,
lowerValue: 25.0,
upperValue: 50.0,
divisions: 5,
showValueIndicator: true,
valueIndicatorMaxDecimals: 1,
onChanged: null,
),
)

//
// Add custom value formatter
//
..add(
frs.RangeSlider(
min: 0.0,
max: 100.0,
lowerValue: _lowerValueFormatter,
upperValue: _upperValueFormatter,
divisions: 10,
showValueIndicator: true,
valueIndicatorFormatter: (int index, double value) {
String twoDecimals = value.toStringAsFixed(2);
return '$twoDecimals mm';
},
onChanged: (double newLowerValue, double newUpperValue) {
setState(() {
_lowerValueFormatter = newLowerValue;
_upperValueFormatter = newUpperValue;
});
},
),
),
),
),
),
);
}

// -----------------------------------------------
// Creates a list of RangeSliders, based on their
// definition and SliderTheme customizations
// -----------------------------------------------
List<Widget> _buildRangeSliders() {
List<Widget> children = <Widget>[];
for (int index = 0; index < rangeSliders.length; index++) {
children
.add(rangeSliders[index].build(context, (double lower, double upper) {
// adapt the RangeSlider lowerValue and upperValue
setState(() {
rangeSliders[index].lowerValue = lower;
rangeSliders[index].upperValue = upper;
});
}));
// Add an extra padding at the bottom of each RangeSlider
children.add(SizedBox(height: 8.0));
}

return children;
}

// -------------------------------------------------
// Creates a list of RangeSlider definitions
// -------------------------------------------------
List<RangeSliderData> _rangeSliderDefinitions() {
return <RangeSliderData>[
RangeSliderData(
min: 0.0, max: 100.0, lowerValue: 10.0, upperValue: 100.0),
RangeSliderData(
min: 0.0,
max: 100.0,
lowerValue: 25.0,
upperValue: 75.0,
divisions: 20,
overlayColor: Colors.red[100]),
RangeSliderData(
min: 0.0,
max: 100.0,
lowerValue: 10.0,
upperValue: 30.0,
showValueIndicator: false,
valueIndicatorMaxDecimals: 0),
RangeSliderData(
min: 0.0,
max: 100.0,
lowerValue: 10.0,
upperValue: 30.0,
showValueIndicator: true,
valueIndicatorMaxDecimals: 0,
activeTrackColor: Colors.red,
inactiveTrackColor: Colors.red[50],
valueIndicatorColor: Colors.green),
RangeSliderData(
min: 0.0,
max: 100.0,
lowerValue: 25.0,
upperValue: 75.0,
divisions: 20,
thumbColor: Colors.grey,
valueIndicatorColor: Colors.grey),
];
}
}

// ---------------------------------------------------
// Helper class aimed at simplifying the way to
// automate the creation of a series of RangeSliders,
// based on various parameters
//
// This class is to be used to demonstrate the appearance
// customization of the RangeSliders
// ---------------------------------------------------
class RangeSliderData {
double min;
double max;
double lowerValue;
double upperValue;
int divisions;
bool showValueIndicator;
int valueIndicatorMaxDecimals;
bool forceValueIndicator;
Color overlayColor;
Color activeTrackColor;
Color inactiveTrackColor;
Color thumbColor;
Color valueIndicatorColor;
Color activeTickMarkColor;

static const Color defaultActiveTrackColor = const Color(0xFF0175c2);
static const Color defaultInactiveTrackColor = const Color(0x3d0175c2);
static const Color defaultActiveTickMarkColor = const Color(0x8a0175c2);
static const Color defaultThumbColor = const Color(0xFF0175c2);
static const Color defaultValueIndicatorColor = const Color(0xFF0175c2);
static const Color defaultOverlayColor = const Color(0x290175c2);

RangeSliderData({
this.min,
this.max,
this.lowerValue,
this.upperValue,
this.divisions,
this.showValueIndicator: true,
this.valueIndicatorMaxDecimals: 1,
this.forceValueIndicator: false,
this.overlayColor: defaultOverlayColor,
this.activeTrackColor: defaultActiveTrackColor,
this.inactiveTrackColor: defaultInactiveTrackColor,
this.thumbColor: defaultThumbColor,
this.valueIndicatorColor: defaultValueIndicatorColor,
this.activeTickMarkColor: defaultActiveTickMarkColor,
});

// Returns the values in text format, with the number
// of decimals, limited to the valueIndicatedMaxDecimals
//
String get lowerValueText =>
lowerValue.toStringAsFixed(valueIndicatorMaxDecimals);
String get upperValueText =>
upperValue.toStringAsFixed(valueIndicatorMaxDecimals);

// Builds a RangeSlider and customizes the theme
// based on parameters
//
Widget build(BuildContext context, frs.RangeSliderCallback callback) {
return Container(
width: double.infinity,
child: Row(
children: <Widget>[
Container(
constraints: BoxConstraints(
minWidth: 40.0,
maxWidth: 40.0,
),
child: Text(lowerValueText),
),
Expanded(
child: SliderTheme(
// Customization of the SliderTheme
// based on individual definitions
// (see rangeSliders in _RangeSliderSampleState)
data: SliderTheme.of(context).copyWith(
overlayColor: overlayColor,
activeTickMarkColor: activeTickMarkColor,
activeTrackColor: activeTrackColor,
inactiveTrackColor: inactiveTrackColor,
//trackHeight: 8.0,
thumbColor: thumbColor,
valueIndicatorColor: valueIndicatorColor,
showValueIndicator: showValueIndicator
? ShowValueIndicator.always
: ShowValueIndicator.onlyForDiscrete,
),
child: frs.RangeSlider(
min: min,
max: max,
lowerValue: lowerValue,
upperValue: upperValue,
divisions: divisions,
showValueIndicator: showValueIndicator,
valueIndicatorMaxDecimals: valueIndicatorMaxDecimals,
onChanged: (double lower, double upper) {
// call
callback(lower, upper);
},
),
),
),
Container(
constraints: BoxConstraints(
minWidth: 40.0,
maxWidth: 40.0,
),
child: Text(upperValueText),
),
],
),
);
}
}
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