isComplete method
Implementation
bool isComplete() {
// It is important to not directly return false in the for boucle because
// in the case a subform is present in the fields, it needs this call
// to display error.
bool isComplete = true;
for (final Field field in fields) {
if (field.validator(field.value) != null) {
isComplete = false;
}
}
return isComplete;
}