I want to show a button only if the new value is different from the old one. But its not working, the button isn't showing

class ViewPatientPage extends StatefulWidget {
  final int status;
  final String name;
  const ViewPatientPage({required this.status, required this.name, super.key});

  @override
  State<ViewPatientPage> createState() => _ViewPatientPageState();
}

class _ViewPatientPageState extends State<ViewPatientPage> {
  String name = '';
  @override
  void initState() {
    super.initState();
    name = widget.name;
  }

  SizedBox space() {
    return const SizedBox(height: 15);
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        FocusManager.instance.primaryFocus?.unfocus();
      },
      child: Scaffold(
        appBar: AppBar(
          actions: [
           (name != widget.name) ? TextButton(
                onPressed: () {},
                child: const Text(
                  'Editar',
                  style: TextStyle(color: Colors.white),
                )): const SizedBox.shrink()
          ],
        ),
        body: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 10),
          child: Column(
            children: [
              space(),
              TextFormField(
                initialValue: widget.name,

                // keyboardType: keyboardType,
                validator: (val) {
                  if (val.toString().isEmpty || val == null || val == '') {
                    return 'Fill field';
                  }
                  return null;
                },
                decoration: InputDecoration(
                    label: const Text('Name'),
                    contentPadding: const EdgeInsets.symmetric(horizontal: 20),
                    border: OutlineInputBorder(
                        borderSide: const BorderSide(color: Colors.black),
                        borderRadius: BorderRadius.circular(20))),
                onChanged: (value) {
                  name = value.trim();
                  print(name);
                  print('widget ${widget.name}');
                },
                // inputFormatters: inputFormatters,
              ),
              space(),
            ],
          ),
        ),
      ),
    );
  }
}

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CodePudding user response：

You need to call setState() in onChanged.

Something like:

onChanged: (value) {
          setState(() {
            name = value.trim();
          });
          print(name);
          print('widget ${widget.name}');
        },

CodePudding user response：

Call setState inside onChanged function setState(() { name = value.trim(); });

CodePudding user response：

To update the UI, you have to a call a setState() in the onChanged: (value) {}

setState(()
{
...

});