adaptive_scrollbar

Language: English

Adaptive Scrollbar is a library that allows you to create one or more desktop-style scrollbars on a single screen, each of which is bound only to its own object and placed in its own place on the screen.

• How to use it
• Multiple scrollbars
• Customization
• Slider scroll-to-click speed
• Parameters

How to use it

Just wrap with AdaptiveScrollbar your widget that contains your ScrollView object and specify the controller that is attached to this ScrollView object.

AdaptiveScrollbar(
  controller: controller,
  child: Center(
    child: ListView.builder(
      controller: controller,
      itemBuilder: (context, index) { 
        return Text(
            "Line " + index.toString());
      },
      itemCount: 50,
    ))),

Multiple scrollbars

You can add multiple scrollbars to the screen at once. The controller is a required parameter in order to track changes to only one object if there are several ScrollView objects in your widget.

return AdaptiveScrollbar(
  controller: verticalScroll,
  width: verticalWidth,
  child: AdaptiveScrollbar(
    controller: horizontalScroll,
    width: horizontalWidth,
    position: ScrollbarPosition.bottom,
    underSpacing: EdgeInsets.only(bottom: verticalWidth),
    child: SingleChildScrollView(
      controller: horizontalScroll,
      scrollDirection: Axis.horizontal,
      child: Container(
        width: 2000,
        child: Container(
          color: Colors.lightBlueAccent,
          child: ListView.builder(
            controller: verticalScroll,
            itemCount: 30,
            itemBuilder: (context, index) {
              return Container(
                height: 30,
                child: Text("Line " + index.toString()));
            }))),
    )));

Customization

You can position your scrollbar on any of the 4 sides of the screen. There is only one thing - if you choose ScrollbarPosition.top or ScrollbarPosition.bottom, your scrollbar will actually be rotated 90 degrees, and the top will be on the left. Do not forget about this if you specify the spacings for slider and under the slider part. I'll think about how to simplify this.

AdaptiveScrollbar(
  controller: verticalScroll,
  width: verticalWidth,
  child: AdaptiveScrollbar(
    controller: horizontalScroll,
    position: ScrollbarPosition.bottom,
    
    //the horizontal scrollbar will have a padding
    // on the RIGHT by the width of the vertical scrollbar
    underSpacing: EdgeInsets.only(bottom: verticalWidth),
    
    width: horizontalWidth,
    child: ...
),

To set slider width, you can set the horizontal sliderSpacing. The vertical sliderSpacing will determine the padding of the slider from the start and the end of the bottom. The height of the slider is determined automatically based on the size of the ScrollView object. If ScrollView object has nowhere to scroll, the scrollbar will not be displayed on the screen.

You can set colors for slider and under the slider part, or completely set the decorations for them.

Slider scroll-to-click speed

You can set your own speed parameters for moving the slider in the direction of the click. scrollToClickDelta is the distance that the slider will move in one move. scrollToClickFirstDelay is the duration of the first delay between the slider moves in the direction of the click, in milliseconds. scrollToClickOtherDelay is the duration of the remaining delays between scrolls in the click direction, in milliseconds.

AdaptiveScrollbar(
  ...
  scrollToClickDelta: 75,
  scrollToClickFirstDelay: 200,
  scrollToClickOtherDelay: 50,
  ...
),

Parameters

Parameter	Description	Type	Default value
child	Widget that contains your ScrollView.	Widget	required
controller	Controller that attached to ScrollView object.	ScrollController	required
position	Position of scrollbar on the screen.	ScrollbarPosition (enum)	ScrollbarPosition.right
width	Width of all scrollBar.	double	16.0
sliderHeight	Height of slider. If you set this value, there will be this height. If not set, the height will be calculated based on the content, as usual.	double	Calculated based on content
sliderChild	Child widget for slider.	Widget?	-
underColor	Under the slider part of the scrollbar color.	Color	Colors.white
sliderDefaultColor	Default slider color.	Color	Colors.blueGrey
sliderActiveColor	Active slider color.	Color	sliderDefaultColor.withRed(10)
underDecoration	Under the slider part of the scrollbar decoration.	BoxDecoration	BoxDecoration(shape: BoxShape.rectangle, color: underColor)
sliderDecoration	Slider decoration.	BoxDecoration	BoxDecoration(shape: BoxShape.rectangle, color: sliderDefaultColor)
sliderActiveDecoration	Slider decoration during pressing.	BoxDecoration	BoxDecoration(shape: BoxShape.rectangle, color: sliderActiveColor)
scrollToClickDelta	Offset of the slider in the direction of the click.	double	100.0
scrollToClickFirstDelay	Duration of the first delay between scrolls in the click direction, in milliseconds.	int	400
scrollToClickOtherDelay	Duration of the others delays between scrolls in the click direction, in milliseconds.	int	100
underSpacing	Under the slider part of the scrollbar spacing. Don't forget about rotation that depends on position.	EdgeInsetsGeometry	const EdgeInsets.all(0.0)
sliderSpacing	Slider spacing from bottom. Don't forget about rotation that depends on position.	EdgeInsetsGeometry	const EdgeInsets.all(2.0)