Change the keyboard type for a TextFormField in a Form

Question

I have a text form that accepts letters and numbers and the keyboard changes dynamically. It's working but when I delete the code, the numeric keyboard remains Here is the example

    final _controller = TextEditingController();
    var keyboardType = TextInputType.text;
    FocusNode _focusNode = FocusNode();
    
TextFormField(
    style: TextStyle(
    color: Colors.black,
    fontSize: 50,
    fontWeight: FontWeight.w700),
     decoration:
    InputDecoration(labelText: "code", hintText: 'ABC1234'),
    controller: _controller,
    focusNode: _focusNode,
    textCapitalization: TextCapitalization.characters,
    keyboardType: keyboardType,
    onChanged: (value) {
     if (value.length == 3) {
    FocusScope.of(context).unfocus();
     setState(() {
     keyboardType = TextInputType.number;
    });
    
     Future.delayed(Duration(milliseconds: 150)).then((value) {
     FocusScope.of(context).requestFocus();
    
    });
       } else {
        setState(() {
     keyboardType = TextInputType.text;
       });
       }
      }),

Answer 1

That's because it's already open. you will have to do the same steps you did to show it as a numeric keyboard

i.e

else {
FocusScope.of(context).unfocus();
 setState(() {
 keyboardType = TextInputType.text;
});

 Future.delayed(Duration(milliseconds: 150)).then((value) {
 FocusScope.of(context).requestFocus();

});

also, this way of handling the condition will result in closing and reopening of keyboard in many cases, you should make it as follows

if (value.length == 3 && keyboardType == TextInputType.text) {
//....
} else if (value.length < 3 && keyboardType != TextInput.text) {