How to give a “Dashed Border” in flutter?

Question

I try to give dashed border in flutter but there is no option for dashed border in flutter. so any another way to create dashed border in futter.

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Answer 1

Image

Use this component:

import 'dart:math';

import 'package:flutter/material.dart';

class CircularBorder extends StatelessWidget {

  final Color color;
  final double size;
  final double width;
  final Widget icon;

  const CircularBorder({Key key, this.color = Colors.blue, this.size = 70, this.width = 7.0, this.icon}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      height: size,
      width: size,
      alignment: Alignment.center,
      child: Stack(
        alignment: Alignment.center,
        children: <Widget>[
          icon == null ? Container() : icon,
          CustomPaint(
            size: Size(size, size),
            foregroundPainter: new MyPainter(
                completeColor: color,
                width: width),
          ),
        ],
      ),
    );
  }
}

class MyPainter extends CustomPainter {
  Color lineColor =  Colors.transparent;
  Color completeColor;
  double width;
  MyPainter(
      { this.completeColor, this.width});
  @override
  void paint(Canvas canvas, Size size) {
    Paint complete = new Paint()
      ..color = completeColor
      ..strokeCap = StrokeCap.round
      ..style = PaintingStyle.stroke
      ..strokeWidth = width;

    Offset center = new Offset(size.width / 2, size.height / 2);
    double radius = min(size.width / 2, size.height / 2);
    var percent = (size.width *0.001) / 2;

    double arcAngle = 2 * pi * percent;
    print("$radius - radius");
    print("$arcAngle - arcAngle");
    print("${radius / arcAngle} - divider");

    for (var i = 0; i < 8; i++) {
      var init = (-pi / 2)*(i/2);

      canvas.drawArc(new Rect.fromCircle(center: center, radius: radius),
          init, arcAngle, false, complete);
    }


  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }
}

Using:

CircularBorder(
          width: 6,
          size: 55,
          color: Colors.grey,
          icon: Icon(Icons.access_alarm, color: Colors.grey),
        ),

Answer 2

For rounded corners using this, you can use

    CornerRadius = 10.0;

    return DottedBorder(
      color: Colors.black,
      strokeWidth: 3,
      radius: Radius.circular(CardRadius),
      dashPattern: [10, 5],
      customPath: (size) {
        return Path()
          ..moveTo(CardRadius, 0)
          ..lineTo(size.width - CardRadius, 0)
          ..arcToPoint(Offset(size.width, CardRadius), radius: Radius.circular(CardRadius))
          ..lineTo(size.width, size.height - CardRadius)
          ..arcToPoint(Offset(size.width - CardRadius, size.height), radius: Radius.circular(CardRadius))
          ..lineTo(CardRadius, size.height)
          ..arcToPoint(Offset(0, size.height - CardRadius), radius: Radius.circular(CardRadius))
          ..lineTo(0, CardRadius)
          ..arcToPoint(Offset(CardRadius, 0), radius: Radius.circular(CardRadius));
      },
      child: Container(...)
    }

This is what it looks like

Answer 3

You can use dashPattern, an attribute which allows you to specify the Dash Sequence by passing in an Array of Doubles.

DottedBorder(
    dashPattern: [6, 3, 2, 3], 
    child: ...
);

This code gives a dashed sequence of width 6, space 3, width 2, space 3,.... and this continues.

To get a Dashed line across the screen, use

DottedBorder(
  color: Color(0xFFE9EBF5),
  strokeWidth: 1,
  radius: Radius.circular(10),
  dashPattern: [5, 5],
  customPath: (size) {
    return Path()
      ..moveTo(0, 10)
      ..lineTo(size.width, 10);
  },
  child: Container(),
),

Answer 4

I am using dotted_border plugin for this-

import 'package:flutter/material.dart';

import 'package:dotted_border/dotted_border.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
          appBar: AppBar(
            title: Text('Dotted Border'),
          ),
          body: SafeArea(
            child: Center(
              child: Padding(
                padding: const EdgeInsets.all(8.0),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.center,
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                    container1,
                    Spacer(),
                    container2,
                    Spacer(),
                    container3,
                    Spacer(),
                    container4,
                  ],
                ),
              ),
            ),
          )),
    );
  }

  Widget get container1 {
    return DottedBorder(
      padding: EdgeInsets.all(4),
      dashPattern: [9, 5],
      child: Container(
        height: 110,
        width: double.maxFinite,
        decoration: BoxDecoration(
          color: Color(0xff994444),
        ),
      ),
    );
  }

  Widget get container2 {
    return DottedBorder(
      padding: EdgeInsets.all(8),
      dashPattern: [6],
      borderType: BorderType.Circle,
      child: Container(
        height: 210,
        width: double.maxFinite,
        decoration: ShapeDecoration(
          shape: CircleBorder(),
          color: Color(0xff444499),
        ),
      ),
    );
  }

  Widget get container3 {
    return DottedBorder(
      padding: EdgeInsets.all(4),
      borderType: BorderType.RRect,
      radius: Radius.circular(20),
      child: Container(
        height: 120,
        width: double.maxFinite,
        decoration: ShapeDecoration(
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
          color: Color(0xff994444),
        ),
      ),
    );
  }

  Widget get container4 {
    return DottedBorder(
      borderType: BorderType.Oval,
      dashPattern: [8,4,2,4],
      child: Container(
        height: 180,
        width: double.maxFinite,
        decoration: ShapeDecoration(
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
          color: Color(0x22888888),
        ),
      ),
    );
  }
}

Answer 5

As long as it is a Rectangular dashed border you want, you can now use dotted_border package which I have uploaded to Pub.

Usage

DottedBorder(
  color: Colors.black,
  gap: 3,
  strokeWidth: 1,
  child: FlutterLogo(size: 148),
)