Flutter TextButton is there but not displaying - flutter

Question

I've been updating a Flutter app and replaced a FlatButton with the new TextButton. But now the button doesn't display on the Card. I can click it and it works, and if I long press you can see the button and it's caption.
The card widget code is below.
Card otherSwapCard(
List<FSRows?> data, int index, context, Function circularprogress) {
String? shiftDate = formatJsonDate(data[index]!.shiftDate!, 'dd/MM/yyyy');
//calculate time value string
String shiftTimes =
'${formatJsonTime24To12(data[index]!.startTime!)} - ${formatJsonTime24To12(data[index]!.finishTime!)}';
return Card(
color: Colors.white,
elevation: 3,
margin: EdgeInsets.fromLTRB(16, 4, 16, 12),
child: Container(
decoration: BoxDecoration(
border: Border(
top: BorderSide(
width: 2.0,
color: kMainColor40,
),
),
),
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Row(
children: <Widget>[
Expanded(
flex: 72,
child: Column(
children: <Widget>[
DataKeyRow(dkLabel: 'Job:', dkValue: data[index]!.jobName!),
SizedBox(height: 2),
DataKeyRow(dkLabel: 'Date:', dkValue: shiftDate!),
SizedBox(height: 2),
DataKeyRow(
dkLabel: 'Time:', dkValue: shiftTimes.toLowerCase()),
],
),
),
Expanded(
flex: 28,
child: Center(
child: TextButton(
style: ButtonStyle(
foregroundColor: MaterialStateProperty.all<Color>(Colors.blue),
),
child: Text('Fill', style: TextStyle(color: Colors.white)),
onPressed: () { },
),
),
),
],
),
),
),
);
}

Answer 1

Card, TextButton, and Text three are in white color. So trying changing the color of the Button or Text.
To change the TextButton color
TextButton(
onPressed: () {},
style: TextButton.styleFrom(
primary: Colors.white,
backgroundColor: Colors.black, // Background Color
),
child: const Text(
'Text Button ',
style: TextStyle(fontSize: 24),
),
)
The backgroundColor will change the TextButton background color to black and the primary will change the font color to white, you can customize it accordingly.

Answer 2

Both your Card color and TextButton Text color are White, you just need to change one of them.
I copied your code and change the color and everything went fine.
Card(
color: Colors.white,
TextButton(
style: ButtonStyle(
foregroundColor: MaterialStateProperty.all<Color>(Colors.blue),
),
child: Text('Fill', style: TextStyle(color: Colors.**white**)),
onPressed: () { },
),

Answer 3

Card and TextButton both are in white color , so try changing your code.
Change
child: Text('Fill', style: TextStyle(color: Colors.white)),
to
child: Text('Fill', style: TextStyle(color: Colors.black)),