signup.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (TextUtils.isEmpty(username.getText().toString()) ||
                        TextUtils.isEmpty(editTextPhone.getText().toString()) ||
                        TextUtils.isEmpty(password.getText().toString())) {
                    errorText.setText("Please enter valid information");
                    return;
                }

                if (!PASSWORD_PATTERN.matcher(password.getText().toString()).matches()) {
                    errorText.setText("Password must contain at least one digit, one uppercase letter, one lowercase letter, one special character, and be 8-16 characters long.");
                    return;
                }

                if (username.getText().toString().contains(" ")) {
                    errorText.setText("No spaces should be in the username");
                    return;
                }

                checkUsernameAvailability(username.getText().toString(), new UsernameAvailabilityListener() {
                    @Override
                    public void onUsernameAvailable() {
                        if (!phoneCode.isValidFullNumber()) {
                            Toast.makeText(phoneLogin.this, "Phone number not valid", Toast.LENGTH_SHORT).show();
                            return;
                        }
                        Intent intent = new Intent(phoneLogin.this, otpVerification.class);
                        intent.putExtra("phone", phoneCode.getFullNumberWithPlus());
                        startActivity(intent);
                    }

                    @Override
                    public void onUsernameUnavailable() {
                        Toast.makeText(phoneLogin.this, "Username not available", Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onError() {
                        Toast.makeText(phoneLogin.this, "Error checking username availability, please try again later.", Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });