setPersistenceEnabled(true) crashes app - firebase

Question

I’m creating my first Firebase App. One of its requirements is that it run when the network is not available. The Firebase guide states:
Enabling disk persistence allows our app to also keep all of its state even after an app restart. We can enable disk persistence with just one line of code.
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
With disk persistence enabled, our synced data and writes will be persisted to disk across app restarts and our app should work seamlessly in offline situations.
Another requirement is to use Google Sign In. So in my MainActivity I check if the User is signed in, if not, I launch the SignInActivity. (The SignInActivity is from the Firebase examples.) The SignInActivity works, the user gets logged in, and MainActivity is launched for a second time. Now my app crashes on the code line FirebaseDatabase.getInstance().setPersistenceEnabled(true); with the following message:
Calls to setPersistenceEnabled() must be made before any other usage of FirebaseDatabase instance.
Now if I restart my app, the User is signed in, the SignInActivity is not launched, my app runs fine.
Any suggestions of how I avoid this crash after the User signs in?
As I was posting this question, I received a suggestion to relocate FirebaseDatabase.getInstance().setPersistenceEnabled(true);
to my “Application class”. I get exactly the same result … SignInActivity starts, completes, and I get a crash on the setPersistenceEnabled.
Below is my MainActivity onCreate:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Calls to setPersistenceEnabled() must be made before any other usage of FirebaseDatabase instance.
// Crash here upon returning from SignInActivity.
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
mFirebaseDbReference = FirebaseDatabase.getInstance().getReference();
// Initialize Firebase Auth
mFirebaseAuth = FirebaseAuth.getInstance();
mFirebaseUser = mFirebaseAuth.getCurrentUser();
if (mFirebaseUser == null) {
// Not signed in, launch the Sign In activity
Timber.tag("MainActivity").i("onCreate(): User not signed in, launching SignInActivity");
startActivity(new Intent(this, SignInActivity.class));
finish();
} else {
mUsername = mFirebaseUser.getDisplayName();
Timber.tag("MainActivity").i("onCreate(): User \"%s\" signed in.", mUsername);
if (mFirebaseUser.getPhotoUrl() != null) {
mPhotoUrl = mFirebaseUser.getPhotoUrl().toString();
}
}

Answer 1

A FirebaseApp is initialized by a ContentProvider so it is not initialized at the time onCreate() is called.
Get your FirebaseDatabase like this:
public class Utils {
private static FirebaseDatabase mDatabase;
public static FirebaseDatabase getDatabase() {
if (mDatabase == null) {
mDatabase = FirebaseDatabase.getInstance();
mDatabase.setPersistenceEnabled(true);
}
return mDatabase;
}
}
Then call Utils.getDatabase() from any activity you want.
Read more in this article

Answer 2

I fixed this exception by using setPersistenceEnabled(true) in my Application class.
public class MApplication extends Application {
#Override
public void onCreate() {
super.onCreate();
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
}
}
In AndroidManifest.xml, set the application name as MApplication:
<application
android:name=".MApplication"
... />

Answer 3

I was facing a similar problem and using a static variable seemed to resolve the issue for me. So at first my code looked something like this
#Override
protected void onCreate(Bundle savedInstanceState) {
//..code
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
FirebaseDatabase database = FirebaseDatabase.getInstance();
//..code
}
and now it looks more like
static boolean calledAlready = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
//..code
if (!calledAlready)
{
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
calledAlready = true;
}
FirebaseDatabase database = FirebaseDatabase.getInstance();
//..code
}
Hope it helps!

Answer 4

I bit late but today i got this issue, I solved by adding
static {
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
}
to my Activity

Answer 5

To me, it is easier to be handled by creating a separate class for Firebase. This is because Firebase has its own instance and if you are using it in more than one activity, there's the possibility for it to crash if you call setPersistenceEnabled again in another activity.
Another good thing is that you can pass your context or parameters into the FirebaseHandler constructor if required. Or if you have fixed location in the database, they can be called easy without the .child("location") boilerplate.
Example:
public class FirebaseHandler {
// parameters
private Context context;
private String userKey;
private DatabaseReference databaseReference;
private static boolean isPersistenceEnabled = false;
private static String fixedLocationA = "locationA";
private static String fixedLocationB = "locationB";
public FirebaseHandler(Context context, String userKey) {
this.context = context; // context can be used to call PreferenceManager etc.
this.userKey = userKey;
if (!isPersistenceEnabled) {
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
isPersistenceEnabled = true;
}
databaseReference = FirebaseDatabase.getInstance().getReference().child(userKey);
}
public DatabaseReference getRefA() {
return databaseReference.child(fixedLocationA);
}
public DatabaseReference getRefB() {
return databaseReference.child(fixedLocationB);
}
}
This can then be called in any Activity as below.
public class MyActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// get instance
FirebaseHandler firebaseHandler = new FirebaseHander(this, "userKey");
// to set value
firebaseHandler.getRefA().setValue("value");
// to set listener
firebaseHandler.getRefB().addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
// TODO here....
// also, can remove listener if required
if (certain condition) {
firebaseHandler.getRefB().removeEventListener(this);
}
}
}
}
}

Answer 6

I'm facing some problem too, but this is my temporary solution for my app.
Create BaseActivity extends AppcompatActivity and override onCreate, put setPersistenceEnabled there.
public class BaseActivity extends AppCompatActivity {
private static String TAG = "BaseActivity";
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try{
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
Log.d(TAG,FirebaseDatabase.getInstance().toString());
}catch (Exception e){
Log.w(TAG,"SetPresistenceEnabled:Fail"+FirebaseDatabase.getInstance().toString());
e.printStackTrace();
}
}
}
And change MainActivity to extend BaseActivity
public class MainActivity extends BaseActivity
EDIT: Follow #imakeApps answer
public class BaseActivity extends AppCompatActivity {
private static String TAG = "BaseActivity";
static boolean isInitialized = false;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try{
if(!isInitialized){
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
isInitialized = true;
}else {
Log.d(TAG,"Already Initialized");
}
}catch (Exception e){
e.printStackTrace();
}
}
}

Answer 7

Solved it by making the Firebase reference a static class field like this:
public class MainActivity extends AppCompatActivity
private static FirebaseDatabase fbDatabase;
#Override
protected void onCreate(Bundle savedInstanceState) {
if(fbDatabase == null) {
fbDatabase = FirebaseDatabase.getInstance();
fbDatabase.setPersistenceEnabled(true);
}
It's no problem to create new Firebase references (without setPersistenceEnabled(true)) in other activities too.

Answer 8

If you don't like the static fields, this did the trick for me:
if (FirebaseApp.getApps(context).isEmpty()) {
FirebaseApp.initializeApp(context);
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
}
This can be caused be more that one process initializing twice firebase or Multidex apps. For more info see this: https://github.com/firebase/quickstart-android/issues/15

Answer 9

I wouldn't recommend using Application to store the data because like its written in CodePath
There is always data and information that is needed in many places within your app. This might be a session token, the result of an expensive computation, etc. It might be tempting to use the application instance in order to avoid the overhead of passing objects between activities or keeping those in persistent storage.
However, you should never store mutable instance data inside the Application object because if you assume that your data will stay there, your application will inevitably crash at some point with a NullPointerException. The application object is not guaranteed to stay in memory forever, it will get killed. Contrary to popular belief, the app won’t be restarted from scratch. Android will create a new Application object and start the activity where the user was before to give the illusion that the application was never killed in the first place.
Thats the reason I would recommend using a Singleton like this:
public class DataBaseUtil {
private static FirebaseDatabase mDatabase;
public static FirebaseDatabase getDatabase() {
if (mDatabase == null) {
mDatabase = FirebaseDatabase.getInstance();
mDatabase.setPersistenceEnabled(true);
}
return mDatabase;
}}
just use it in your code then like
private FirebaseDatabase fdb = DataBaseUtil.getDatabase();

Answer 10

Create a class called Util.java
and add following code
public class Util {
private static FirebaseDatabase mData;
public static FirebaseDatabase getDatabase() {
if (mData == null) {
mData = FirebaseDatabase.getInstance();
mData.setPersistenceEnabled(true);
}
return mData;
}
}
Now replace FirebaseDatabase.getIntance() with Util.getDatabase() every time in each activity. Calling just once will get the error!

Answer 11

I was facing same issue. i changed code as below.
BEFORE(Causing Crash)
var rootRef = FIRDatabase.database().reference()
override func viewDidLoad() {
super.viewDidLoad()
FIRDatabase.database().persistenceEnabled = true
}
AFTER (Resolved Crash)
var rootRef:FIRDatabaseReference!
override func viewDidLoad() {
super.viewDidLoad()
FIRDatabase.database().persistenceEnabled = true
rootRef = FIRDatabase.database().reference()
}

Answer 12

In Menifest
android:name=".AppName
Create java Class that extends Application
public class AppName extends Application {
#Override
public void onCreate() {
super.onCreate();
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
}

Answer 13

Make sure that .setpersistenceenabled(true) is not happening twice, while sign in by Google in your case, second care setPersistenceEnabled(true) is must be called before any instance of firebase called this resolve my issue.

Answer 14

For Kotlin Try this:
class DatabaseUtil {
companion object {
private val firebaseDatabase: FirebaseDatabase = FirebaseDatabase.getInstance()
init {
firebaseDatabase.setPersistenceEnabled(true)
}
fun getDatabase() : FirebaseDatabase {
return firebaseDatabase
}
}
}

Answer 15

Simply move you code in ExampleFragment.class from onCreateView method to onCreate method:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
}
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
....
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_home, container, false);

Answer 16

The error message describes the problem:
Calls to setPersistenceEnabled() must be made before any other usage
of FirebaseDatabase instance.
The fix to this problem is described into the documentation: As in SDK 2.x, persistence of the disk must be enabled before other calls to the database are made.
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
https://firebase.google.com/support/guides/firebase-android

Answer 17

You can use:
FirebaseDatabase.getInstance().setPersistenceEnabled(true);
before using FirebaseDatabase.getInstance().getReference();