Firebase Implementation freezes app while downloading data

Question

This is my Service class which is calling to all listener

public class DBService extends Service {

private static final String TAG = DBService.class.getName();
private DatabaseReference reference;

private static final String FIREBASE_EMAIL = "xxxxxxx@workindia.in";
private static final String FIREBASE_PASSWORD = "xxxxxx";

@Override
public void onCreate() {
    super.onCreate();

    FirebaseDatabase database = FirebaseDatabase.getInstance();
    reference = database.getReference();
}


@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    FirebaseAuth auth = ((StartApplication) getApplication()).getAuth();
    FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

    if (user == null) {

        String email = ObjectGraph.getEmployeeProfile().getEmail();
        String password = ObjectGraph.getEmployeeProfile().getMobile_no();
        if (password != null && !password.trim().isEmpty()) {
            if (email == null || email.trim().isEmpty()) {
                email = password + FIREBASE_EMAIL;
            }
            signIn(auth, email, FIREBASE_PASSWORD);
        }
    } else {
        addListeners();
    }
    return START_STICKY;

}

@Override
public IBinder onBind(Intent intent) {
    addListeners();
    return null;
}

private void signIn(final FirebaseAuth auth, final String email, final String password) {

    Log.i(TAG, "Login");
    auth.signInWithEmailAndPassword(email, password)
            .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {

                    if (task.isSuccessful()) {
                        boolean isResetTimeStamp = true;
                        setTimeStamp(isResetTimeStamp);
                        addListeners();
                    } else {
                        register(auth, email, password);
                    }
                }
            });

    FirebaseAuth.AuthStateListener authListener = new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
            FirebaseUser user = firebaseAuth.getCurrentUser();
            if (user != null) {
                Log.e(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
            } else {
                Log.e(TAG, "onAuthStateChanged:signed_out");
            }
        }
    };

    auth.addAuthStateListener(authListener);
}

private void addListeners() {
    EmployeeProfile profile = ObjectGraph.getEmployeeProfile();
    if (profile != null && profile.getMobile_no() != null && !profile.getMobile_no().trim().isEmpty()) {
        reference.child(AppConstants.WORKINDIA_USERS_LAST_TIME).child(profile.getMobile_no().trim()).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                Map<String, Object> child = (Map<String, Object>) dataSnapshot.getValue();
                Log.e(TAG, "DATA " + child);
                if (child == null) {

                /*Query Listener Other listener*/
                    Query recentPostsQuery = reference.child(AppConstants.WORKINDIA_JOB_NODE).limitToFirst(1000);//.orderByChild("timestamp");
                    recentPostsQuery.addValueEventListener(jobBulKDownloadListener);

                } else {

                    long lastSyncTime = (Long) child.get(AppConstants.TIMESTAMP);
                    Log.e(TAG, "DATA " + lastSyncTime);

                /*Query Listener Other listener*/
                    Query recentPostsQuery = reference.child(AppConstants.WORKINDIA_JOB_NODE)
                            .orderByChild(AppConstants.TIMESTAMP)
                            .startAt(lastSyncTime)
                            .limitToFirst(1000);//.orderByChild("timestamp");
                    recentPostsQuery.addValueEventListener(jobBulKDownloadListener);
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                Log.e(TAG, databaseError.getMessage(), databaseError.toException());
            }
        });
    }
}



private void register(final FirebaseAuth auth, final String email, final String password) {
    Log.e(TAG, "register");
    auth.createUserWithEmailAndPassword(email, password)
            .addOnCompleteListener(new OnCompleteListener<AuthResult>() {

                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if (task.isSuccessful()) {
                        Log.e(TAG, "register true");
                        signIn(auth, email, password);
                    } else {
                        Log.e(TAG, "register fail");
                    }
                }

            });
}


ValueEventListener jobBulKDownloadListener = new ValueEventListener() {
    @Override
    public void onDataChange(final DataSnapshot dataSnapshot) {

        Toast.makeText(getApplicationContext(), "jobBulKDownloadListener+ onDataChange", Toast.LENGTH_SHORT).show();
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    if (dataSnapshot != null) {
                        long time = System.currentTimeMillis();
                        Log.d(TAG, "Start Process : " + (System.currentTimeMillis() - time) / 1000 + " Seconds");
                        List<Job> jobs = new ArrayList<Job>();
                        for (DataSnapshot snapshot : dataSnapshot.getChildren()) {

                            WrapperJob job1 = snapshot.getValue(WrapperJob.class);
                            Job job = job1.getData();
                            jobs.add(job);
                        }


                        if (jobs.size() > 0) {
                            parseJobs(jobs);
                        }
                        Log.d(TAG, "After Process : " + (System.currentTimeMillis() - time) / 1000 + " Seconds");
                    }
                } catch (Exception e) {
                    Log.e(TAG, e.getMessage(), e);
                    Crashlytics.logException(e);
                }
            }
        }).start();
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        Log.e(TAG, databaseError.getMessage(), databaseError.toException());
    }
};


private void parseJobs(List<Job> jobs) {

    /* Job Operations*/
}

 }

Why it is getting hanged ?? I have kept almost everything on background thread

Answer 1

This may not be the problem, but in your jobBulKDownloadListener it's probably safer to operate on the DataSnapshot on the main thread instead of your worker thread. You could refactor it like this:

ValueEventListener jobBulKDownloadListener = new ValueEventListener() {
    @Override
    public void onDataChange(final DataSnapshot dataSnapshot) {
        Toast.makeText(getApplicationContext(), "jobBulKDownloadListener+ onDataChange", Toast.LENGTH_SHORT).show();

        if (dataSnapshot != null) {
            final List<Job> jobs = new ArrayList<Job>();
            for (DataSnapshot snapshot : dataSnapshot.getChildren()) {

                WrapperJob job1 = snapshot.getValue(WrapperJob.class);
                Job job = job1.getData();
                jobs.add(job);
            }

            if (jobs.size() > 0) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            long time = System.currentTimeMillis();
                            Log.d(TAG, "Start Process : " + (System.currentTimeMillis() - time) / 1000 + " Seconds");
                            parseJobs(jobs);
                            Log.d(TAG, "After Process : " + (System.currentTimeMillis() - time) / 1000 + " Seconds");
                        } catch (Exception e) {
                            Log.e(TAG, e.getMessage(), e);
                            Crashlytics.logException(e);
                        }
                    }
                }).start();
            }
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        Log.e(TAG, databaseError.getMessage(), databaseError.toException());
    }
};