Errors with registration form Validation using setError() in Android

Question

Actually I am trying to validate a registration form before submitting it.So after clicking the submit Button,Each field has to be validated and based on the validation results

Answer 1

    private EditText edt_firstName,edt_email;
     private String firstName,email;

    edt_firstName = findViewById(R.id.edt_firstName);
    edt_email = findViewById(R.id.edt_email);

     private void validateData(){
     firstName = edt_firstName.getText().toString().trim();
     email = edt_email.getText().toString().trim();
    if (!firstName.isEmpty() && !email.isEmpty() && isValidEmail(email) {
    //here api call of the register user.
    }else{
    if (firstName.isEmpty()) {
                    edt_firstName.setError("Please Enter First Name");
                    edt_firstName.requestFocus();
                }
     else if (email.isEmpty()) {
                    edt_email.setError("Please Valid Email Id");
                    edt_email.requestFocus();
                } else if (!isValidEmail(email)) {
                    edt_email.setError("Please Enter Valid Email");
                    edt_email.requestFocus();
                }
    }
    }

private static boolean isValidEmail(String email) {
        return !TextUtils.isEmpty(email) && Patterns.EMAIL_ADDRESS.matcher(email).matches();
    }