I have a form that takes email and password. So after entering the data first I checked the email is already available in document (in Firebase firestore database) or not. If not available then I will insert those data. But my code always inserts first before executing the check for what already exists. Is any way I can solve it without using my insert code inside the checking code.
For example, my database already has "[email protected]" document. When I input the same email and submit then it will show Account available. Can not sign up! But my code inserts again then check for the email availability in DB.
Thank you for sharing your valuable time.
XML Code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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=".MainActivity"
android:orientation="vertical"
android:paddingTop="30dp">
<View
android:layout_width="400dp"
android:layout_height="1dp"
android:background="#678049"
android:layout_gravity="center"
android:layout_marginTop="10dp"
android:layout_marginBottom="30dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_marginTop="5dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Email"
android:textSize="20dp"
android:textColor="@color/black"
android:layout_marginLeft="5dp"
android:layout_gravity="center|top"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_marginTop="5dp">
<EditText
android:id="@ id/UserEmail"
android:layout_width="345dp"
android:layout_height="40dp"
android:textSize="20dp"
android:background="#5676"
android:hint="Enter Email Adress.."
android:inputType="text"
android:layout_marginLeft="3dp"/>
</LinearLayout>
<Space
android:layout_width="match_parent"
android:layout_height="5dp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_marginTop="5dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Password"
android:textColor="@color/black"
android:textSize="20dp"
android:layout_marginLeft="5dp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center"
android:layout_marginTop="5dp">
<EditText
android:id="@ id/UserPassword"
android:layout_width="345dp"
android:layout_height="40dp"
android:textSize="20dp"
android:background="#5676"
android:hint="Enter Password.."
android:layout_marginVertical="13dp"
android:inputType="textPassword" />
</LinearLayout>
<Button
android:id="@ id/btnSubmit"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="15dp"
android:padding="10dp"
android:layout_marginHorizontal="80dp"
android:backgroundTint="#4C4B4B"
android:text="Sign up"
android:textColor="#F5FBF6" />
</LinearLayout>
Java Code
public class MainActivity extends AppCompatActivity {
public static final String COLLECTION_USER = "collection_user";
EditText userEmail, userPassword;
Button btnSignUp;
boolean accountAlreadyAvailable = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
userEmail = findViewById(R.id.UserEmail);
userPassword = findViewById(R.id.UserPassword);
btnSignUp = findViewById(R.id.btnSubmit);
btnSignUp.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String email = userEmail.getText().toString();
String password = userPassword.getText().toString();
Map<String, Object> data = new HashMap<>();
data.put("email", email);
data.put("password", password);
FirebaseFirestore db = FirebaseFirestore.getInstance();
db.collection(COLLECTION_USER).document(email)
.get()
.addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if(task.getResult().exists()) {
accountAlreadyAvailable = true;
Log.d(TAG, "Account available changed to: " accountAlreadyAvailable);
}
}
});
//As no email document found,
//new data will insert to firebase firestore database
Log.d(TAG, "Account available: " accountAlreadyAvailable);
if(accountAlreadyAvailable == false) {
db.collection(COLLECTION_USER).document(email).set(data).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if(task.isSuccessful()) {
Log.d(TAG, "Data inserted as no account found");
}
}
});
} else {
Log.d(TAG, "Account available. Can not sign up!");
}
}
});
}
}
CodePudding user response：
Data is loaded from Firestore (and most modern cloud APIs) asynchronously, which changes the order in which the code executed from what you may be used to. It's easiest to see this by setting breakpoints and running in the debugger, or by adding some logging:
Log.i("Firestore", "Before calling get()");
FirebaseFirestore db = FirebaseFirestore.getInstance();
db.collection(COLLECTION_USER).document(email)
.get()
.addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
Log.i("Firestore", "Got data");
}
});
Log.i("Firestore", "After calling get()");
When you run this code, it logs:
Before calling get()
After calling get()
Got data
This may not be the order in which you expected the code to execute, but it is working as designed and perfectly explains why your second read from the database doesn't work: by the time that runs accountAlreadyAvailable = true hasn't executed yet.
The solution for this type of problem is always the same: any code that needs the data from the database, has to be inside the onComplete, be called from there, or be otherwise sychronized.
The simplest fix is to move the second read operation into the onComplete of the first:
FirebaseFirestore db = FirebaseFirestore.getInstance();
db.collection(COLLECTION_USER).document(email)
.get()
.addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if(task.getResult().exists()) {
accountAlreadyAvailable = true;
Log.d(TAG, "Account available changed to: " accountAlreadyAvailable);
}
//