Attempt to invoke virtual method 'android.text.Editable com.rengwuxian.materialedittext.MaterialEditText.getText()' - nullpointerexception

Question

please help me
Pressing the register button does not return a toast message, the app stops, and the following code:
java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable com.rengwuxian.materialedittext.MaterialEditText.getText()' on a null object reference
I also used String.ofValue instead of toString.
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();
}
}
});
}
}

Answer 1

Copy my codes and compare your codes with mine
Java Code
Look carefully at the Java code
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 fileds are required", Toast.LENGTH_SHORT).show();
}else if (txt_password.length() < 6){
Toast.makeText(RegisterActivity.this, "password must be at least 6 characters", Toast.LENGTH_SHORT).show();
} else {
register(txt_username, txt_email, txt_password);
}
}
});
}
private void register(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 woth this email or password", Toast.LENGTH_SHORT).show();
}
}
});
}
}
XML Code
Look carefully at the xml code
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".RegisterActivity">
<include
android:id="#+id/toolbar"
layout="#layout/bar_layout"/>
<LinearLayout
android:layout_width="match_parent"
android:orientation="vertical"
android:gravity="center_horizontal"
android:layout_below="#+id/toolbar"
android:padding="16dp"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Create a new account"
android:textSize="20sp"
android:textStyle="bold"/>
<com.rengwuxian.materialedittext.MaterialEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/username"
android:layout_marginTop="10dp"
app:met_floatingLabel="normal"
android:hint="Username"/>
<com.rengwuxian.materialedittext.MaterialEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/email"
android:inputType="textEmailAddress"
android:layout_marginTop="10dp"
app:met_floatingLabel="normal"
android:hint="Email"/>
<com.rengwuxian.materialedittext.MaterialEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/password"
android:inputType="textPassword"
android:layout_marginTop="10dp"
app:met_floatingLabel="normal"
android:hint="Password"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="register"
android:id="#+id/btn_register"
android:background="#color/colorPrimaryDark"
android:layout_marginTop="10dp"
android:textColor="#fff"/>
</LinearLayout>
</RelativeLayout>