CODEWITHSUNDEEP
androidfirebasefirebase-realtime-database
DIRR Red
DIRR Red

Reputation: 11

Firebase onDataChange returns null value after internet reconnection

I have this code to read data and write the value into an object

if(SpecialFunction.isNetworkAvailable()) {
    databaseContent.loadAccountFromDatabase(account -> {
        this.account = account;
        binding.textView3.setText(account.toString());
    });
} else {
    startActivity(new Intent(this, InternetTroubleActivity.class));
}

Where databaseContent is a class which contains Firebase logic which I need. In loadAccountFromDatabase I have next code which works with one problem.

  public void loadAccountFromDatabase(FirebaseCallbackAccount accountFirebaseCallback) {
     ValueEventListener valueEventListener = new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
            if (snapshot.exists()) {
                account = snapshot.getValue(Account.class);
            } else {
                account = new Account();
                setDefaultAccount();
            }
            accountFirebaseCallback.onCallback(account);
        }
        @Override
        public void onCancelled(@NonNull DatabaseError error) {
            Log.e("loadAccountFromDatabase", "Error:  " + error.toString());
        }
    };
    database.addValueEventListener(valueEventListener);
}

When I try to read data after internet reconnection or when I turn on internet after onStart() and run loadAccountFromDatabase I get null value of my snapshot. I have a method (isNetworkAvailable()) which works well and when I don't have internet connection it returns false. The next part of code doesn't work properly. The snapshot.exists returns true and snapshot.getValue returns null although the value is other.

if (snapshot.exists()) {
    account = snapshot.getValue(Account.class);
}

If I run an application with internet connection everything works well while I don't turn off internet and try to read again. I also tried to use database.get().addOnCompleteListener(onCompleteListener)... but I got the same result. Everything works well while I don't try to read data after internet reconnection.

database.keepSynced(true) also doesn't help.

UPDATE##

Database init:

private final String USER_KEY = "Account", PURCHASES = "purchases";

    public void init() {
        mAuth = FirebaseAuth.getInstance();
        firebaseDatabase = FirebaseDatabase.getInstance();
        database = firebaseDatabase.getReference(String.format("%s/%s", USER_KEY, mAuth.getUid()));
    }

Structure: console

UPDATE 2##

To help you understand the problem I add screenshot of log. GREEN box: I run my app with internet connection. The data was read and wrote correct. RED box: I closed my app, destroyed activity, turned off internet. Then I run my app, but method isNetworkAvailable didn't let me run MainActivity. Then I turned on internet and clicked on button. The data was being tried to read but I got object with null variables althrough they are not null. If you think that something is wrong with isNetworkAvailable I tell you that this problem was before I have added it. I was hoping that it would help me to read correct but it didn't help. logcat

UPDATE 3##

JSON:

{
  "Account" : {
    "wBOZsnGGywYIpap3cLZodPOWcpt2" : {
      "budget" : 100,
      "budgetLastMonth" : 0,
      "budgetLeft" : 100,
      "currencyType" : "USD",
      "email" : "[email protected]",
      "id" : "wBOZsnGGywYIpap3cLZodPOWcpt2",
      "personName" : "новый пользователь"
    }
  }
}

Upvotes: 0

Views: 57

Answers (1)

DIRR Red
DIRR Red

Reputation: 11

I found a problem. 4 hours of reading my code and stackoverflow. I don't know how, but in onPause () I had code that writes null object to a database. So when I tested and turned on / off the Internet, I run it. So I wrote a null object that was not instantly updated on the console, and when I turned on the Internet, the object was updated to zero in the database and then read in my app. :]

Upvotes: 1

Related Questions