Hide form fields based on value of other form fields?

[joshuakoh1]

Using _fbKey.currentState.fields['dependent_field'].currentState.value does not work, throws the error that customState was called on null

[Dennis-Mwea]

@joshuakoh1 You could use Visibility() widget and set visible to either true or false depending on the value of the other field.

[joshuakoh1]

@Dennis-Mwea Do you mean I'll declare a separate bool value on init then set that with onChanged of the form field that is responsible for the visibility value? Because my current setup throws an error "NoSuchMethodError: The method '[]' was called on null" as the state has not been initialised unless the form has been submitted.

 Visibility(
                            visible: this._fbKey.currentState?.fields['dependent_field']?.currentState.value,
                            maintainState: true,
                            child: Text('Hello'),
                          ),

[Dennis-Mwea]

@joshuakoh1 Yeah you have to declare separate bool value on init then set that with onChanged of the form field that is responsible for the visibility value. This is what I did

                  bool enterAddressManually = false;



                   Container(
                      margin: EdgeInsets.only(
                        top: 10.0,
                        bottom: enterAddressManually ? 0.0 : 16.0,
                      ),
                      child: RichText(
                        text: TextSpan(
                          text: 'Enter address manually',
                          style: TextStyle(
                            color: Colors.white,
                            fontFamily: 'Gibson',
                            fontSize: 12.0,
                            fontWeight: FontWeight.w400,
                            height: 1.4,
                          ),
                          recognizer: TapGestureRecognizer()
                            ..onTap = () {
                              setState(() {
                                enterAddressManually = true;
                              });
                            },
                        ),
                      ),
                    ),
                    Visibility(
                      visible: enterAddressManually,
                      child: FormBuilderDropdown(
                        attribute: "address",
                        style: TextStyle(color: Colors.white),
                        initialValue: selectedAddress,
                        onChanged: (val) {
                          setState(() {
                            selectedAddress = val;
                            address = addresses
                                .where(
                                    (address) => address.id == selectedAddress)
                                .toList()
                                .first;
                          });
                        },
                        validators: [
                          FormBuilderValidators.required(
                            errorText: 'Please choose your address.',
                          ),
                        ],
                        items: List.generate(
                          addresses.length,
                          (index) => DropdownMenuItem(
                            value: index,
                            child: Text('${addresses[index].address_1}'),
                            onTap: () {
                              setState(() {
                                address1Controller.text =
                                    addresses[index].address_1;
                                address2Controller.text =
                                    addresses[index].address_2;
                                address3Controller.text =
                                    addresses[index].address_3;
                                cityController.text = addresses[index].city;
                                countyController.text = addresses[index].county;
                              });
                            },
                          ),
                        ),
                      ),
                    ),

[deandreamatias]

Hi @joshuakoh1!
This still an issue?

[deandreamatias]

Due to lack of response and an old error, I will close this issue.
If the bug still exists, feel free to open a new issue