Question

Nice to meet you. I am new to Dart and want to make good use of this library.

There is one thing I want to ask.

Although onSelectionEnd is commented that its definition takes a function with a parameter of (int init, int end) as an argument, it is actually a function that takes three parameters.

I would like you to teach me the role of each parameter. Thank you.

My usage

Center(
  child: SingleCircularSlider(
    12,
    3,
    handlerColor: Colors.black,
    onSelectionEnd: (a, b, c) {
         // I do not figure out what a, b, c parameters mean.
    },
    baseColor: Colors.grey.withOpacity(0.5),
    selectionColor: Colors.deepPurple,
  ),
),

DoubleCircularSlider(
  48,
  0,
  10,
  height: 230.0,
  width: 230.0,
  primarySectors: 4,
  secondarySectors: 12,
  baseColor: Color.fromRGBO(255, 255, 255, 0.1),
  selectionColor: Theme.of(context).primaryColor,
  handlerColor: Color(0xFFEEEEEE),
  onSelectionChange: (int initTime, int endTime, int laps) {
    setState(() {
      this.initTime = initTime;
      this.endTime = endTime;
    });
  },
  child: Padding(
    padding: const EdgeInsets.all(42.0),
    child: Center(
        child: Text('${_formatIntervalTime(initTime, endTime)}',
            style: TextStyle(fontSize: 36.0, color: Colors.white))),
  ),
),

Hot reloading properly updates the state (updates the time)

Is there a way to prevent the user from increasing the slider? Eg. only being able to decrease it until 0? If yes, any tips how someone would do it?

I want that the drag happens from one side so always the init is 0 and you can't change it and only one circle to drag ?

Are there any plans to convert this library to null safety?

It would be useful for some use cases to allow making the SingleCircularSlider selection direction be counter-clockwise.

Is there s way to customize sectors width, height and color?
Also - is there a way change appearance of handlers, like using your own widgets?

It's a must-have for any modern flutter library

Repro steps:

1. create a DoubleCircularSlider.
2. drag start point to end point -> crash
3. drag end point past start point -> crash

So essentially laps are completely broken too.

It would be nice to be able to specify using a dashed line for the base line.

The section lines can be more customizable and I wish for that right now

https://github.com/davidanaya/flutter-circular-slider/blob/master/lib/src/base_painter.dart#L37-L43

    if (primarySectors > 0) {
      _paintSectors(primarySectors, 8.0, selectionColor, canvas);
    }

    if (secondarySectors > 0) {
      _paintSectors(secondarySectors, 6.0, baseColor, canvas);
    }

the radiusPadding can be made customizable and the secondarySector should not use the baseColor, but rather allow a custom one and default to baseColor

Any tip on how would you implement constraints like:

• defining MIN and MAX allowed values (at the beginning and at the end of a circle)
• constraining the range so that 'init' value is always less than 'end' value
• constraining all range values not to exceed [MIN, MAX] range (meaning disabling 'laps')

For example, if a use case would be selecting time range in a single day, there is no obvious way how to achieve this.

Thanks!

I want to make a design like speedOmeter with the handle and same dragging event like yours. Can you please help me to build that? Or suggest the way to build half circle?

Hi,
Great work on the sliders. Just a quick query, lets say there is only one handler, then instead of dragging, is it possible to click somewhere on the circle and the handler to move there. This is similar to how linear slider in flutter would work. Thanks!

In our case, the CircularSlider is inside a SingleChildScrollView and it seems that it gets all the gestures 99% of the times we try to drag.

Hello,

I am trying to use circular slider with many instances. I am creating different objects but every time the position does not change even though I am setting it with a different value.

Is it possible to use your widget with multiple instances?

Thanks.

能更新一下代码吗，

Hi David, great package! Can you please add the ability to set an initial lap value? I am using your slider to create values, lets say in increments of 200, and saving both the total value and the laps. If the value is 500, I would have laps = 2, and the slider would be at 50%. When I initialize the slider at another time, I want the slider to know that the lap count is 2...not 0. So when I decrement the slider it allows me to reset the value from 500 back to 0. Without a lap initialized, I cannot decrement back to 0. Thank you!

When I decide to change the value of selectionColor and handlerColor through a changenotifierProvider, the color does not change until I slightly move the slider.

in the article you wrote here

https://itnext.io/how-to-build-a-circular-slider-in-flutter-cab3fc5312df

how did you get the line to split the circle ?

is it possible to have only one hadler ( the thing that you drag ) ?

Many thanks

Great work !

The section lines can be more customizable and I wish for that right now

https://github.com/davidanaya/flutter-circular-slider/blob/master/lib/src/base_painter.dart#L37-L43

    if (primarySectors > 0) {
      _paintSectors(primarySectors, 8.0, selectionColor, canvas);
    }

    if (secondarySectors > 0) {
      _paintSectors(secondarySectors, 6.0, baseColor, canvas);
    }```

the `radiusPadding` can be made customizable and the secondarySector should not use the baseColor, but rather allow a custom one and default to baseColor

Hi, would be great to be able to use onSelectionChange to control/validate the values (thus enabling user logic like max interval size or similar...).

I need to change slider position not only by user interaction, but from code as well. My build() function returns this widget:

FractionallySizedBox(
      widthFactor: 0.5,
      child: Container(
        color: Colors.redAccent,
        child: SingleCircularSlider(
            255,
            entity.brightness ?? 0
         ),
      ),
    )

Changing the value of entity.brightness and rebuilding the widget didn't change it's position.

So simply the bug happen when the start is at 0 and stays in 0 and you drag the end to 0 the slider disappear