Flutter Text Form Field - flutter

Question

i want to hide the second text form field if the first starts with a
if i write any word in the first text form field that starts with a the second disappear
TextFormField(
controller: firstColorController,
decoration:const InputDecoration(
border: OutlineInputBorder(),
hintText: "first color"
),
validator: (query){
if(query!.isEmpty){
return "color can't be empty";
}else if(query.trim().length<5||query.trim().length>9){
return "colors can't be less than 5 chars or greater than 9 chars";
}
else if(checkFirstColor(query.trim())){
return cubit.errorMessage;
}
},
),
const SizedBox(height: 15,),
if(firstColorController.text.startsWith("a"))
TextFormField(
controller: secondColorController,
decoration:const InputDecoration(
border: OutlineInputBorder(),
hintText: "second color"
),
validator: (value){
if(value!.isEmpty){
return "value can't be empty";
}
return null;
},
),

Answer 1

Here's an example.
bool secondVisible = true;
TextEditingController firstCtl = TextEditingController();
TextEditingController secondCtl = TextEditingController();
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
children: [
TextFormField(controller: firstCtl, onChanged: (){
setState(() {
secondVisible = firstCtl.text.startsWith('a');
});
},),
Visibility(
visible: secondVisible,
child: TextFormField(controller: secondCtl)
),
],
),
),
);
}