How to put multiple validation on a textfeild - validation

Question

i have textFeilds i put empty feild validation but i don't know how to put another validation(Multiple validation) like "Email is invalid" or whatever i want. This is just important code, all code is a lill lengthy
final TextEditingController _emailControl = new TextEditingController();
bool _validateEmail = false;
child: TextField(
style: TextStyle(
fontSize: 15.0,
color: Colors.black,
),
decoration: InputDecoration(
contentPadding: EdgeInsets.all(10.0),
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(5.0),
borderSide: BorderSide(color: Colors.white,),
),
enabledBorder: OutlineInputBorder(
borderSide: BorderSide(color: Colors.white,),
borderRadius: BorderRadius.circular(5.0),
),
hintText: "Email",
prefixIcon: Icon(
Icons.mail_outline,
color: Colors.black,
),
hintStyle: TextStyle(
fontSize: 15.0,
color: Colors.black,
),
labelText: 'Email',
errorText: _validateEmail ? 'Email Can\'t Be Empty' : null,
),
maxLines: 1,
controller: _emailControl,
),
My registration button press is below
onPressed: () {
setState(() {
_emailControl.text.isEmpty ? _validateEmail = true : _validateEmail = false;
if ( _validateEmail == false ){
_isLoading = true;
khan();
}
});

Answer 1

Use TextFormField.
TextFormField(
validator(val):{
if(val.isEmpty){
return "This field cannot be empty",
}
else if(next conditon){
return ....
}
}
style: TextStyle(
fontSize: 15.0,
color: Colors.black,
),
decoration: InputDecoration(
contentPadding: EdgeInsets.all(10.0),
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(5.0),
borderSide: BorderSide(color: Colors.white,),
),
enabledBorder: OutlineInputBorder(
borderSide: BorderSide(color: Colors.white,),
borderRadius: BorderRadius.circular(5.0),
),
hintText: "Email",
prefixIcon: Icon(
Icons.mail_outline,
color: Colors.black,
),
hintStyle: TextStyle(
fontSize: 15.0,
color: Colors.black,
),
labelText: 'Email',
errorText: _validateEmail ? 'Email Can\'t Be Empty' : null,
),
maxLines: 1,
controller: _emailControl,
),
And finally use form to validate the textfield.