flutter space between inputTextForm field and bottom border

Question

Everything works fine except the space between the elements/user input and bottom bar. I tried different methods to get rid of that space: content padding, box constraints, prefix icon constraints etc. None worked. Eventually I limited the height of this widget, but then my error message was placed on top of user input and I was getting this message Another exception was thrown: BoxConstraints has a negative minimum height.
Here is the code:

 Widget _emailField(FormBloc formBloc) {
    return StreamBuilder(
        stream: formBloc.email,
        builder: (context, AsyncSnapshot<String> snapshot) {
          return TextFormField(
            autofocus: false,
            keyboardType: TextInputType.emailAddress,
            autovalidateMode: AutovalidateMode.onUserInteraction,
            validator: (value) {
              if (value == null) {
                return "Email cannot be empty";
              } else {
                if (value.isEmpty) {
                  return "Email cannot be empty";
                }
              }
            },
            onChanged: formBloc.changeEmail,
            textInputAction: TextInputAction.next,
            decoration: InputDecoration(
              prefixIcon: const Icon(
                Icons.email,
                size: 15,
              ),
              contentPadding: const EdgeInsets.all(0),
              labelText: "Email",
              labelStyle: const TextStyle(fontSize: 14),
              errorText:
                  snapshot.error != null ? snapshot.error as String : null,
            ),
          );
        }
      );
  }

I need to make everything work as before, except this time I do need to have no space between bottom border and input elements, how can I do so?

Answer 1

First inside InputDecoration(), you can give zero padding to your prefix icon. Then set prefixIconConstraints to BoxConstraints(maxHeight:0) Still isn't enough you can give negative value to contentPadding: EdgeInsets.only(bottom:-5),.

InputDecoration(
          prefixIcon: Padding(
            padding: EdgeInsets.only(right:10),
            child:const Icon(
              Icons.email,
              size: 15,
            ),
          ),
          prefixIconConstraints: BoxConstraints(maxHeight:0),
          contentPadding: EdgeInsets.only(bottom:-5),
          labelText: "Email",
          labelStyle: const TextStyle(fontSize: 14),
          errorText:"error",
        )