Basically, I am looking for FormFieldState.isValid but for FormState.
So the challenge is that I want to enable/disable my form submit button on the fly depending on whether all the form fields are valid, without calling FormState.validate() until the submit button is actually clicked because that will report errors for the yet invalid fields.
im keeping an extra variable around for isValid and storing it in a stream so everytime a field changes we ask if its valid and notify our isValid variable, its possible this might become out of sync with the form at some point so isnt ideal but it kind of works
From docs:
bool validate() - Calls FormField.validator to set the errorText. Returns true if there were no errors.
So if we want to validate without setting the errorText we should use FormField.validator directly.
This is exactly what isValid property does!
bool isValid - True if the current value is valid. This will not set errorText or hasError and it will not update error display.
Looping button logic to one-time check of isValid inside a build() method will not update the button. The way I can think of is a setState() on every text change. The easiest way to detect all changes is probably subscribe to all TextEditingControllers.
bool allFormsAreValid = false;
void revalidate() {
final allValid = [formStateA, formStateB, ...].all((f) => f.isValid);
if (allValid != allFormsAreValid) {
setState(() => allFormsAreValid = allValid);
}
}
void initState() {
myControllerA.listen(revalidate);
myControllerB.listen(revalidate);
...
}
// use allFormsAreValid inside `build`
IMHO not showing error messages and not showing the button is a strange user experience. It was never intended this way and code will look ugly.
Try using FormState.save()
In this way, all your items in the form will be saved and the validation will not be triggered ( as it is triggered using FormState.validate() or FormState.saveAndvalidate() )
This will update the form validity. Checking with FormState.isValid, if all the fields are not empty, will return true ( false otherwise ).
// permitConfigFormKey is the key of the FormBuilder
void funcWithoutFormValidation(){
final form = permitConfigFormKey.currentState;
if (form != null) {
form.save(); // in this way validation will not be triggered
if(form.isValid){
//do something...
}
}
Can you try reseach about AutovalidateMode on FormField ? I think They will some option for this case.
/// Used to configure the auto validation of [FormField] and [Form] widgets.
enum AutovalidateMode {
/// No auto validation will occur.
disabled,
/// Used to auto-validate [Form] and [FormField] even without user interaction.
always,
/// Used to auto-validate [Form] and [FormField] only after each user
/// interaction.
onUserInteraction,
}
Please refer to below code
Solution 1: AutovalidateMode is enabled always
class HomeScreen extends StatelessWidget {
HomeScreen({Key key}) : super(key: key);
final TextEditingController addressController = TextEditingController();
final FocusNode addressFocus = FocusNode();
final TextEditingController stateController = TextEditingController();
final FocusNode stateFocus = FocusNode();
final _validationKey = GlobalKey<FormState>();
int validateAddress(String address) {
String patttern = r'(^[a-zA-Z0-9 ,.-]*$)';
RegExp regExp = new RegExp(patttern);
if (address.isEmpty || address.length == 0) {
return 1;
} else if (address.length < 10) {
return 3;
} else {
return 0;
}
}
int validateState(String state) {
String patttern = r'(^[a-zA-Z0-9 ,.-]*$)';
RegExp regExp = new RegExp(patttern);
if (state.isEmpty || state.length == 0) {
return 1;
} else {
return 0;
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.lightBlue,
automaticallyImplyLeading: true,
leading: Icon(
Icons.arrow_back,
),
title: Text("Example"),
centerTitle: true,
),
body: Container(
padding: EdgeInsets.all(15.0),
child: Column(
children: [
Form(
key: _validationKey,
child: Column(
children: [
/* State */
TextFormField(
autovalidateMode: AutovalidateMode.always,
/* autovalidate is set to true */
controller: stateController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.text,
maxLength: 160,
onChanged: (val) {},
maxLines: 1,
validator: (value) {
int res = validateAddress(value);
if (res == 1) {
return "Please enter state";
} else {
return null;
}
},
focusNode: stateFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Enter state" ?? "",
),
),
SizedBox(
height: 15.0,
),
/* Address */
TextFormField(
autovalidateMode: AutovalidateMode.always,
/* autovalidate is enabled */
controller: addressController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.text,
maxLength: 60,
onChanged: (val) {},
maxLines: 1,
validator: (value) {
int res = validateAddress(value);
if (res == 1) {
return "Please enter address";
} else if (res == 3) {
return "Please enter minimum 10 characters";
} else {
return null;
}
},
focusNode: addressFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Enter address" ?? "",
),
),
],
),
),
SizedBox(
height: 15.0,
),
],
),
),
);
}
Solution 2: Validation is enabled only after user interaction
class MainScreen extends StatelessWidget {
MainScreen({Key key}) : super(key: key);
final TextEditingController addressController = TextEditingController();
final FocusNode addressFocus = FocusNode();
final TextEditingController stateController = TextEditingController();
final FocusNode stateFocus = FocusNode();
final _validationKey = GlobalKey<FormState>();
int validateAddress(String address) {
String patttern = r'(^[a-zA-Z0-9 ,.-]*$)';
RegExp regExp = new RegExp(patttern);
if (address.isEmpty || address.length == 0) {
return 1;
} else if (address.length < 10) {
return 3;
} else {
return 0;
}
}
int validateState(String state) {
String patttern = r'(^[a-zA-Z0-9 ,.-]*$)';
RegExp regExp = new RegExp(patttern);
if (state.isEmpty || state.length == 0) {
return 1;
} else {
return 0;
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.lightBlue,
automaticallyImplyLeading: true,
leading: Icon(
Icons.arrow_back,
),
title: Text("Example"),
centerTitle: true,
),
body: Container(
padding: EdgeInsets.all(15.0),
child: Column(
children: [
Form(
key: _validationKey,
child: Column(
children: [
/* State */
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
/* autovalidate is disabled */
controller: stateController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.text,
maxLength: 160,
onChanged: (val) {},
maxLines: 1,
validator: (value) {
int res = validateAddress(value);
if (res == 1) {
return "Please enter state";
} else {
return null;
}
},
focusNode: stateFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Enter state" ?? "",
),
),
SizedBox(
height: 15.0,
),
/* Address */
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
/* autovalidate is disabled */
controller: addressController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.text,
maxLength: 60,
onChanged: (val) {},
maxLines: 1,
validator: (value) {
int res = validateAddress(value);
if (res == 1) {
return "Please enter address";
} else if (res == 3) {
return "Please enter minimum 10 characters";
} else {
return null;
}
},
focusNode: addressFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Enter address" ?? "",
),
),
],
),
),
SizedBox(
height: 15.0,
),
OutlinedButton(
onPressed: () {
_validationKey.currentState.validate();
if (stateController.text.isEmpty) {
stateFocus.requestFocus();
} else if (addressController.text.isEmpty ||
addressController.text.length < 10) {
addressFocus.requestFocus();
}
},
child: Text("Validate"),
)
],
),
),
);
}
}
Solution 3: Autovalidate can also be used but currently its deprecated
class MainScreen extends StatelessWidget {
MainScreen({Key key}) : super(key: key);
final TextEditingController addressController = TextEditingController();
final FocusNode addressFocus = FocusNode();
int validateAddress(String address) {
String patttern = r'(^[a-zA-Z0-9 ,.-]*$)';
RegExp regExp = new RegExp(patttern);
if (address.isEmpty || address.length == 0) {
return 1;
} else if (address.length < 10) {
return 3;
} else {
return 0;
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.lightBlue,
automaticallyImplyLeading: true,
leading: Icon(
Icons.arrow_back,
),
title: Text("Example"),
centerTitle: true,
),
body: Container(
padding: EdgeInsets.all(15.0),
child: Center(
child: TextFormField(
autovalidate: true,
controller: addressController,
inputFormatters: [
FilteringTextInputFormatter.deny(RegExp(r"\s\s")),
FilteringTextInputFormatter.deny(RegExp(
r'(\u00a9|\u00ae|[\u2000-\u3300]|\ud83c[\ud000-\udfff]|\ud83d[\ud000-\udfff]|\ud83e[\ud000-\udfff])')),
],
keyboardType: TextInputType.text,
maxLength: 60,
onChanged: (val) {},
maxLines: 1,
validator: (value) {
int res = validateAddress(value);
if (res == 1) {
return "Please enter address";
} else if (res == 3) {
return "Please enter minimum 10 characters";
} else {
return null;
}
},
focusNode: addressFocus,
autofocus: false,
decoration: InputDecoration(
errorMaxLines: 3,
counterText: "",
filled: true,
fillColor: Colors.white,
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
disabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Color(0xffE5E5E5),
),
),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
),
),
errorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
)),
focusedErrorBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(4)),
borderSide: BorderSide(
width: 1,
color: Colors.red,
),
),
hintText: "Hint Text" ?? "",
),
),
)),
);
}
}
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