Flutter focus textfield without opening softkeyboard?

Question

I'm getting input to my textfield from barcode scanner so I dont need softkeyboard to open when textfield in focus.To achieve that I tried TextInputType.none it hides the keyboard but also can't receive input from scanner.

  TextField(
            keyboardType: TextInputType.none,
            controller: loginTextController,
            focusNode: _loginTextfieldFocus,
            decoration: decoration(context,loginTextController),
            onChanged: (s){
              if(s.contains('\n')||s.contains('\r')){
                Log.d("Enter event found");
              }
            },
          ),

I also tried SystemChannels.textInput.invokeMethod('TextInput.hide'); but it hides only first time. Whenever a character added in textfield softkeyboard becomes visible.