Dialog with flexible height and scrollable content

You can use Column and Flexible.

void showCustomDialog(BuildContext context, String message) async {    await showDialog(      context: context,      builder: (BuildContext context) {        return AlertDialog(          content: Container(            width: double.maxFinite,            child: Column(                mainAxisAlignment: MainAxisAlignment.center,                mainAxisSize: MainAxisSize.min,                children: [                                        Text("Description 1",                      style: TextStyle(fontWeight: FontWeight.bold)),                  SizedBox(height: 8),                  Flexible(                    child: SingleChildScrollView(                      child: Text(message),                    ),                  ),                  ElevatedButton(                    onPressed: () {                       Navigator.of(context).pop();                    },                    child: Text("OK"),                  )                ]),          ),        );      },    );  }

I suggest changing the position of SingleChildScrollView to on top of Column and I hope that should work fine.

Something similar as below:

              height: 200,              width: 300,              child: SingleChildScrollView(                child: Column(                  crossAxisAlignment: CrossAxisAlignment.stretch,                  children: <Widget>[//Your children's column code ]