I need to press a button twice to execute onClickListener - Android

Question

I can't figure out why i need to tap twice on a "submit" button. I have a simple form with 2 TextInputLayouts and a button that calls some logic to be executed, but it gets executed only when i press that button to times.

Follows the code:

XML

<Button
  android:id="@+id/accedibtn"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@+id/pwDimenticataTextViewAccedi"
  android:layout_centerInParent="true"
  android:layout_marginTop="35dp"
  android:text="@string/access"
  android:textColor="@color/black"
  android:textSize="14sp"
  tools:ignore="TextSizeCheck" />

Listener in onCreate method

accedi.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                checkUser(view);
                if (account != null){
                    Routing.dashboardActivity(Login.this, account);
                }
            }
        });

CheckUser Function

private void checkUser(View v){
        String emailString = String.valueOf(email.getText());
        String passwordString = String.valueOf(password.getText());
        
        db.getCOLLECTION_ACCOUNT().whereEqualTo(DatabaseConstants.KEY_ACCOUNT_EMAIL, emailString)
            .get().addOnSuccessListener(queryDocumentSnapshots -> {
                List<DocumentSnapshot> document = queryDocumentSnapshots.getDocuments();
                if(document.size()==1) {
                    String pwCheck = (String) document.get(0).get(DatabaseConstants.KEY_ACCOUNT_PASSWORD);
                    if (passwordString.equals(pwCheck))
                        account = document.get(0).toObject(Account.class);
                }
            }).addOnFailureListener(e -> {
                Toast.makeText(Login.this, Testi.toastError, Toast.LENGTH_SHORT).show();
                    Log.e(TAG, e.toString());
            });
    }

Probably the checkUser function needs to be in another class, I don't know. in any case, I expect that when i tap on button this code will be executed, but it doesn't.

Probably is a simple question, but I have been programming on android for only 2 months

Answer 1

I don't know exactly what kind of a database you are using (maybe Firestore, not important), but .get() seems to be an asynchronous operation as you have the OnSuccessListener and OnFailureListener to handle the outcome.

So, the flow in your app is now:

• Button is clicked
• The operation to read the user account data from the DB is started
• The DB operation is being processed...
• Meanwhile your code proceeds to if (account != null){...}
• The account is still null at that point
• The DB operation is completed at some point and account is no longer null
• The next time the button is clicked account != null is true

Maybe the OnSuccessListener should do the Routing.dashboardActivity()?

Anyway, you'll need to slightly re-think your application logic.