BoxConstraints forces an infinite width

Question

I am getting an error when I add a row in a column. I am getting the following error:

I/flutter ( 6449): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter ( 6449): The following assertion was thrown during performLayout():
I/flutter ( 6449): BoxConstraints forces an infinite width.
I/flutter ( 6449): These invalid constraints were provided to RenderAnimatedOpacity's layout() function

Also for reference here is my code:

return new Scaffold(
      backgroundColor: whiteColor,
      body: new Column(
        children: <Widget>[
          imgHeader,
          lblSignUp,
          txtEmail,
          Row(
            mainAxisAlignment: MainAxisAlignment.start,
            children: <Widget>[
              txtFirstName,
              txtLastName
            ],
          ),
        ],
      ),
    );

score 97 · Accepted Answer · answered Sep 21 '18 at 11:42

97

If you are using TextField Inside a Row then you need to use Flexible or Expanded.

More details are given here in this answer.

https://stackoverflow.com/a/45990477/4652688

answered Sep 21 '18 at 11:42

vipin agrahari

2,691
3
21
31

Nice! `Flexible` produces exactly the sort of behavior that I was looking for. Thank you! =^,^= – Kira Resari Jan 17 '23 at 09:59

score 61 · Answer 2 · answered Feb 29 '20 at 08:45

61

Reason for the error:

TextField expands in horizontal direction and so does the Row, so we need to constrain the width of the TextField, there are many ways of doing it.

Use Expanded

 Row(
  children: <Widget>[
    Expanded(child: TextField()),
    // more widgets
  ],
)

Use Flexible

Row(
  children: <Widget>[
    Flexible(child: TextField()),
    // more widgets
  ],
)

Wrap it in Container or SizedBox and provide width

Row(
  children: <Widget>[
    SizedBox(width: 100, child: TextField()),
    // more widgets
  ],
)

answered Feb 29 '20 at 08:45

CopsOnRoad

237,138
77
654
440

1

I had a ListView that was throwing this exception and wrapping it in a SizedBox and setting the width worked for me! Thanks. – joshpetit Dec 02 '20 at 11:37
1

Flexible() widget saved my day!. Thanks for the answer. – Soorya Jul 13 '21 at 06:58
Giving the reason helped me in a different (ListView) problem. – Paul Sumpner May 31 '22 at 09:00

score 0 · Answer 3 · answered Sep 27 '22 at 07:24

I got this error when using a Positioned widget along the lines of:

Positioned(
  left: _left,
  child: MyWidget(...)
)

And solved by adding the bottom and top arguments, e.g.:

Positioned(
  left: _left,
  bottom: 0,
  top: 0,
  child: MyWidget(...)
)

BoxConstraints forces an infinite width

3 Answers3

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