A borderRadius can only be given for uniform borders

Question

I am getting a warning when using following code but my app is running fine:

════════ Exception caught by rendering library ═════════════════════════════════════════════════════
The following assertion was thrown during paint():
A borderRadius can only be given for uniform borders.
'package:flutter/src/painting/box_border.dart':
Failed assertion: line 510 pos 12: 'borderRadius == null'

Here is my code:

           Container(
              height: screenSize.height*.13,
              width: AppSize.medium,
              decoration: BoxDecoration(
                color: Colors.red,
                border: Border(
                  right: BorderSide(
                    width: 1.0,
                    color: Colors.blue
                  ),
                ),
                borderRadius: BorderRadius.only(
                  topRight: Radius.circular(AppSize.small),
                  bottomRight: Radius.circular(AppSize.small),
                )
              ),
            )

do not pass border radius. It must be null. – Shahzaib Ahmed Jul 01 '22 at 14:46 — Shahzaib Ahmed, Jul 01 '22 at 14:46

ziqq · Answer 1 · 2023-08-15T07:54:58.867

36

Container(
  decoration: BoxDecoration(
    gradient: LinearGradient(
      stops:  [0.02, 0.02],
      colors: [Colors.red, Colors.white]
    ),
    borderRadius: BorderRadius.all(constRadius.circular(6.0))
  )
)

edited Aug 15 '23 at 07:54

answered May 14 '21 at 12:14

ziqq

523
5
11

Nice solution!! – Mehrdad Shokri Jun 11 '21 at 16:22
Will this solution give rounded inner corners of the border if it applied for 2 or more sides of the container? – Preckrasno Sep 27 '21 at 13:12
2

Explain something about problem and solution... – Divyesh mehta Aug 07 '22 at 21:18
what if you cant use Container widget? in a TabBar indicator for example, I can only use BoxDecoration – Texv Aug 14 '23 at 14:35
@Texv all decoration makes in `BoxDecoration` as you noticed, try it or give your minimal example. – ziqq Aug 15 '23 at 07:58
I've raised a new question for it. Please see https://stackoverflow.com/questions/76918645/using-borders-with-tabbar-indicator – Texv Aug 17 '23 at 05:15

score 33 · Answer 2 · answered May 05 '20 at 12:44

33

This is the easiest way that I could came up with... as you can see there's 2 container, the color of outer container is actually the color of the border and the margin of inner container is the strokeWidth of the border and the color of inner container is the background color.

Container(
  decoration: BoxDecoration(
    color: Colors.grey[400],

    borderRadius: BorderRadius.only(
      topLeft: const Radius.circular(15.0),
      topRight: const Radius.circular(15.0),
    ),// BorderRadius

  ),// BoxDecoration
  child: Container(
    margin: const EdgeInsetsDirectional.only(start: 2, end: 2, top: 2),
    decoration: BoxDecoration(
      color: Colors.grey[300],

      borderRadius: BorderRadius.only(
        topLeft: const Radius.circular(13.0),
        topRight: const Radius.circular(13.0),
      ),// BorderRadius

    ),// BoxDecoration
  ),// Container
),// Container

It's a bit silly answer but works! ;)

answered May 05 '20 at 12:44

ehsaneha

1,665
13
8

1

This is great! I extracted this logic into a reusable production-ready widget here: https://gist.github.com/rohan20/d12a709a27511304c853334dd636ba63 With screenshots and a DartPad demo – Rohan Taneja Dec 27 '21 at 09:57
This does not work if the background is not a single color. – Bobin Jan 20 '22 at 06:13
That's a smart approach! – Hitesh Kumar Saini Sep 14 '22 at 17:00
Good for a quick solution (and well packed, as a reusable extracted widget!) but it misses some points: for exemple if the child is a scrollable like a list view, when you hit the end or start of the school you will get a big portion of the color you used as border, which should be just on the border, not the background for that scrollable. – MarcoFerreira Aug 12 '23 at 09:43

score 13 · Answer 3 · answered Nov 12 '19 at 06:52

Flutter is complaining because you only apply a right border to your container, but want to have a border radius as well.

Flutter expects the border to be uniform, i.e. all the way around and in the same color, when applying border radius. If you jump to the sources where the assertion error was thrown you can have a look at the actual assertion.

Ben Villamayor · Answer 4 · 2022-08-26T01:31:40.500

I was struggling with this same error, and found out a simpler solution that's much simpler than the alternatives suggested, which is using a shadow instead of a border.

If you think about it a 1pt border on one side is exactly the same as a shadow without blur that's offset 1pt in that direction.

You can create your Container with the round borders and use decoration to add a shadow to act as your desired border. Here's an example simulating a bottom border:

Container(
  padding: EdgeInsets.symmetric(horizontal: 32.0, vertical: 16),
  decoration: BoxDecoration(
    color: Colors.white,
    borderRadius: BorderRadius.circular(46),
    boxShadow: [
      BoxShadow(
        color: Color(0xFFEEEEEE),
        blurRadius: 0,
        offset: Offset(0, 1),
      ),
    ],
  ),
  child: ...
),

All to this effect:

score 3 · Answer 5 · answered Jul 19 '23 at 03:26

3

Just provide all the other BorderSide (left, top and bottom since you have one for right), and set the width to zero.

answered Jul 19 '23 at 03:26

jovani

669
8
16

I wish i could give you multiple upVotes. You just saved my day.! – IKRAM UL HAQ Aug 21 '23 at 15:22

score 1 · Answer 6 · answered Oct 24 '21 at 00:25

Container(
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.only(
          topRight:
              widget.currentJobIndex == 0 ? Radius.circular(7) : Radius.zero,
          topLeft:
              widget.currentJobIndex == 0 ? Radius.circular(7) : Radius.zero,
        ),
      ),
      child: Container(
        padding: EdgeInsets.only(top: 17, bottom: 20, left: 12, right: 12),
        decoration: BoxDecoration(
            border: Border(bottom: BorderSide(color: AppColors.greyE5))),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text("This is the brief job description"),
            SizedBox(height: 10),
            Row(children: [
              Text(
                "Budget",
                style: TextStyle(fontWeight: FontWeight.bold),
              ),
              Text(":30,000"),
              Spacer(),
              Text(
                "Total Bids",
                style: TextStyle(fontWeight: FontWeight.bold),
              ),
              Text(":32",
                  style: TextStyle(
                      fontWeight: FontWeight.bold,
                      color: Theme.of(context).primaryColor))
            ]),
            SizedBox(height: 10),
            Row(children: [
              Text(
                "Status: Confirmed",
                style: TextStyle(color: Theme.of(context).primaryColor),
              ),
              Spacer(),
              Text(
                "Monday August 22, 2021",
                style: TextStyle(fontSize: responsiveSize(10, context)),
              ),
            ])
          ],
        ),
      ),
    )

I used two containers, the outer one has the border radius, while the inner one has only bottom border. This way Flutter will no longer complain

score 0 · Answer 7 · answered Jul 13 '22 at 13:30

Flutter expects the border to be uniform means all the way around and in the same color when applying border radius.

Check your border color are you applying the same on all sides?

Either you can apply the different color without a radius or you can use the same color with a different radius

score 0 · Answer 8 · answered Nov 10 '22 at 20:34

This is the only solution that is not a workaround. Wrap your widget inside a ClipRect with an border on all sides:

  ClipRect(
    clipper: Customshape(),
    child: Container(
      decoration: BoxDecoration(
        border: Border.all(),
        borderRadius: BorderRadius.all(Radius.circular(5)),
      ),
    ),
  ),

This CustomShape Clipper cuts the border on the left side, which is why the Offsets x value is 2. If you need to clip it on the right side, then set x to 0 and use "size.width - 2".

class CustomShape extends CustomClipper<Rect>{
  @override
  Rect getClip(Size size) => const Offset(2.0, 0) & Size(size.width, size.height);
  @override
  bool shouldReclip(covariant CustomClipper<Rect> oldClipper) => true;
}

A borderRadius can only be given for uniform borders

8 Answers8

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