Managing focus on custom textfield flutter - flutter

Question

I have a general textfield which I am using throughout the app for text inputs and forms. But textfield focus is making the whole form unnatural. To manage focus, I am doing these steps.
First, on MaterialApp:
GestureDetector(
behavior: HitTestBehavior.opaque,
onTap: () {
FocusScope.of(context).requestFocus(FocusNode());
},
child: GetMaterialApp()
),
Then custom textfield:
class CustomTextField extends StatefulWidget {
CustomTextField(
{this.title,
this.controller,
this.hint,
this.hide,
this.maxlines,
this.minLines,
this.validator,
this.onChanged});
final title, controller, hint, hide, maxlines, minLines, validator, onChanged;
#override
_CustomTextFieldState createState() => _CustomTextFieldState();
}
class _CustomTextFieldState extends State<CustomTextField> {
#override
Widget build(BuildContext context) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
alignment: Alignment.center,
decoration: BoxDecoration(
//color: Color(0xffE4E5EA),
borderRadius: BorderRadius.circular(4),
),
child: TextFormField(
onEditingComplete: () {
FocusScope.of(context).unfocus();
},
validator: widget.validator,
controller: widget.controller,
obscureText: widget.hide ?? false,
maxLines: widget.maxlines ?? 1,
minLines: widget.minLines ?? 1,
decoration: InputDecoration(
hintText: widget.hint,
labelText: widget.title,
hintStyle: Theme.of(context)
.textTheme
.bodyText2
.apply(color: Colors.grey),
labelStyle: Theme.of(context).textTheme.subtitle1.apply(
color: Colors.grey[600]),
contentPadding:
const EdgeInsets.symmetric(vertical: 10, horizontal: 15),
focusedBorder: OutlineInputBorder(
borderSide: BorderSide(width: 2, color: Colors.blueAccent)),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.circular(4),
borderSide: BorderSide(color: Colors.grey[400], width: 1.5)),
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(4),
borderSide: BorderSide(color: Colors.grey[200], width: 1.5)),
),
),
),
const SizedBox(height: 10),
],
);
}
}
It works for the most part but when I try to do some task like pick date or file or something, the last used textfield gains focus and keyboard opens. Is there any way to manage focus better way?