회원 가입 시 EditText 입력한 텍스트를 받아올 때,
Toast Message가 출력되지 않고, 앱이 종료되며, NullPointerException이 발생합니다.
java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable com.rengwuxian.materialedittext.MaterialEditText.getText()' on a null object reference
getText()에서 오류가 발생합니다.
```
public class RegisterActivity extends AppCompatActivity {
MaterialEditText username, email, password;
Button btn_register;
FirebaseAuth auth;
DatabaseReference reference;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Register");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
username = findViewById(R.id.username);
email = findViewById(R.id.email);
password = findViewById(R.id.password);
btn_register = findViewById(R.id.btn_register);
auth = FirebaseAuth.getInstance();
btn_register.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String txt_username = username.getText().toString();
String txt_email = email.getText().toString();
String txt_password = password.getText().toString();
if (TextUtils.isEmpty(txt_username) || TextUtils.isEmpty(txt_email) || TextUtils.isEmpty(txt_password)){
Toast.makeText(RegisterActivity.this, "All fields are required", Toast.LENGTH_SHORT).show();
} else if (txt_password.length() < 6){
Toast.makeText(RegisterActivity.this, "password must be at least 6 character", Toast.LENGTH_SHORT).show();
} else {
register(txt_username, txt_email, txt_password);
}
}
});
}
private void register(final String username, String email, String password) {
auth.createUserWithEmailAndPassword(email, password)
.addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()){
FirebaseUser firebaseUser = auth.getCurrentUser();
assert firebaseUser != null;
String userid = firebaseUser.getUid();
reference = FirebaseDatabase.getInstance().getReference("Users" ).child(userid);
HashMap<String, String> hashMap = new HashMap<>();
hashMap.put("id", userid);
hashMap.put("username", username);
hashMap.put("imageURL", "default");
reference.setValue(hashMap).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if (task.isSuccessful()){
Intent intent = new Intent(RegisterActivity.this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
finish();
}
}
});
} else {
Toast.makeText(RegisterActivity.this, "You can't register with this email or password", Toast.LENGTH_SHORT).show();
}
}
});
}
}
```
