"RenderBox was not laid out" text field error in flutter - flutter-layout

Question

I'm trying to put a textfield, the error does not appear, but I think I'm getting a logical error.
I guess sizing is required. But I couldn't understand where to specify.
And the screen is blank.
I don't know if I could explain it properly because my English is not good.
child: Row(
children: <Widget>[
Column(
children: <Widget>[
TextFormField(
decoration: const InputDecoration(
hintText: 'Enter your email',
),
validator: (String? value) {
if (value == null || value.isEmpty) {
return 'Please enter some text';
}
return null;
},
),
const Padding(
padding: EdgeInsets.symmetric(vertical: 16.0),
child: ElevatedButton(
onPressed: null,
child: Text('Submit'),
),
),
],
),
Column(
children: <Widget>[
TextButton(
style: TextButton.styleFrom(
textStyle: const TextStyle(fontSize: 20),
backgroundColor: Colors.blueAccent,
),
onPressed: null,
child: const Text('Button'),
),
Row(
children: <Widget>[
TextButton(
style: TextButton.styleFrom(
textStyle: const TextStyle(fontSize: 20),
backgroundColor: Colors.blueAccent,
),
onPressed: null,
child: const Text('Button2'),
),
],
)
],
)
],
),
),`

Answer 1

Somehow you have to tell Flutter how should it size the two columns in the row. One of the possible solutions is to wrap the first column in an Expanded widget. As a result the second column will be drawn, its size is determined by the text sizes of Button and Button2). And then the first column will occupy all the remaining space, that's what Expanded means. Code:
Row(
children: <Widget>[
Expanded( // <--- this is added, the rest is unchanged
child: Column(
children: <Widget>[
TextFormField(
decoration: const InputDecoration(
hintText: 'Enter your email',
),
validator: (String? value) {
if (value == null || value.isEmpty) {
return 'Please enter some text';
}
return null;
},
),
const Padding(
padding: EdgeInsets.symmetric(vertical: 16.0),
child: ElevatedButton(
onPressed: null,
child: Text('Submit'),
),
),
],
),
),
Column(
children: <Widget>[
TextButton(
style: TextButton.styleFrom(
textStyle: const TextStyle(fontSize: 20),
backgroundColor: Colors.blueAccent,
),
onPressed: null,
child: const Text('Button'),
),
Row(
children: <Widget>[
TextButton(
style: TextButton.styleFrom(
textStyle: const TextStyle(fontSize: 20),
backgroundColor: Colors.blueAccent,
),
onPressed: null,
child: const Text('Button2'),
),
],
)
],
)
],
),