Firebase实时数据库不会更新值

Question

I have been writing an app using firebase database and for the last two days, it doesn't work. What I mean by this is that I have a connection to the database, but when I try to read information by setting addListenerForSingleValueEvent it doesn't run the ValueEventListener even though I updateChildren .

        DatabaseReference mBlaze = FirebaseUtil.getDatabase(PLACES);
        mBlaze.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for (DataSnapshot snapShot : dataSnapshot.getChildren()) {
                    System.out.println("Hello");
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                System.out.println("Error");
            }
        });
        long sTime = System.currentTimeMillis();
        while (!triggers[0])
            if (System.currentTimeMillis() - sTime > 5000)

I have a trigger value in the database used just to run the addListenerForSingleValueEvent .

If I try to run this on my device\\emulator, it won't print out the message "Hello", nor will it print out the message "Error".
The reason this is a problem is that I am trying to verify a code against the firebase database. I give it a 5 second time window for the the value to change, meaning the code was found, and if after 5 second the value of triggers[0] doesn't change, it means the code isn't valid.

During my attempts to reduce the code I have stumble upon the setLogLevel which after I used it with Level.DEBUG , I have found that this line appears over and over again:

Error fetching token: The user's credential is no longer valid. The user must sign in again.

Answer 1

As I stated later on, when I was trying to reduce the code, I found the setLogLevel method, which is used with Level.DEBUG , which I then used to discover the error:

Error fetching token: The user's credential is no longer valid. The user must sign in again.

Which after some snooping around I discovered, that due to the Firebase-Auth mechanism, which grants a user a token for 24 hours, and then de-auth's it, causes the failure to reach the sever.
So the solution would be to implement either a perma-login [permanent login] feature, or every time the user destroys the application or starts it from scratch, check if there is a user logged in using the getCurrentUser() method in FirebaseAuth , and if there is one, log out.

TL;DR:
Make sure you don't have a user signed in for more than 24 hours, and if you do, disconnect them and then reconnect them.