Keyboard is not showing on clicking on TextFormField in flutter android

Question

I'm using TextFormField in flutter app. In my app everywhere It's working fine, But just in one screen it giving me an error. When I click on TextFormField then Keyboard opened and instantly hide automatically. Here is my code for TextFormField.

TextFormField(
                      controller: offerController,
                      maxLines: 1,
                      keyboardType: TextInputType.number,
                      textInputAction: TextInputAction.next,
                      style: GoogleFonts.arimo(
                        textStyle: const TextStyle(
                          color: Color(ColorConstants.TEXT_COLOR_GREY),
                          fontSize: 14.0,
                          fontWeight: FontWeight.w400,
                        ),
                      ),
                      decoration: InputDecoration(
                        border: InputBorder.none,
                        enabledBorder: InputBorder.none,
                        hintText: "Add the Offer Value",
                        hintStyle: GoogleFonts.arimo(
                          textStyle: const TextStyle(
                            color:
                            Color(ColorConstants.COLOR_BFBFBF),
                            fontSize: 14.0,
                            fontWeight: FontWeight.w400,
                          ),
                        ),
                      ),
                    )

Answer 1

Add this to your textFormField.

keyboardType: TextInputType.numberWithOptions(signed: true),
inputFormatters: [
  FilteringTextInputFormatter.digitsOnly,
],

Answer 2

onTap(){
   FocusNode.requestFocus();
}

Answer 3

In this case, if you use the ios emulator, you can see the this link Flutter - Keyboard not showing when TextFormField is selected