com.google.firebase.database.DatabaseException: Serializing Arrays is not supported, please use Lists instead

Question

I am trying to persist a custom object using the following code:

DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference();
DatabaseReference curWorkoutExercisesRef = databaseReference.child("workouts")
            .child(mCurrentWorkout.getId())
            .child("workoutExercises");

WorkoutExercise we = new WorkoutExercise(exercise);
curWorkoutExercisesRef.push().setValue(we);

Here's my object:

public class WorkoutExercise {

    private String id;
    private Exercise exercise;

    public WorkoutExercise() {}

    // getters, setters, other methods 
    // ...
}

public class Exercise {

    private String id;
    private String title;

    private List<BodyPart> bodyParts;

    public Exercise() {}

    // getters, setters, other methods 
    // ...
}

public class BodyPart {

    private String id;
    private String name;

    public BodyPart() {}

    // getters, setters, other methods 
    // ...
}

And every time I am getting this error - com.google.firebase.database.DatabaseException: Serializing Arrays is not supported, please use Lists instead. My objects don't contain any arrays so this error looks quite confusing. I found a way to fix this error - everything works fine if I add the @Exclude annotation to the bodyParts list from my Exercise class but it is obviously not what I am trying to achieve.

So seems that Firebase is unable to persist objects containing inner lists? Are there any straightforward workarounds or best practices here? Thanks!

P.S. I am using firebase-database:9.2.1

I can't reproduce the exception when running with firebase-database:9.2.1. Are you using a different version? — Bob Snyder
– Bob Snyder, Commented Jul 30, 2016 at 14:35
@qbix out of curiosity: when you serialize a List<BodyPart> to the database, what JSON do you end up with? — Frank van Puffelen
– Frank van Puffelen, Commented Jul 30, 2016 at 15:30
@FrankvanPuffelen: The list is serialized as an array. JSON is here — Bob Snyder
– Bob Snyder, Commented Jul 30, 2016 at 15:40

Rbar · Accepted Answer · 2017-10-05 16:23:55Z

21

In case this helps others that are receiving the same error, I was getting the same error and the solution ended up being the following for me:

Changing:

databaseReference.child("somechild").setValue(etName.getText());

To:

databaseReference.child("somechild").setValue(etName.getText().toString());

As @fraggjkee points out, Firebase attempts to serialize getters, and this was the similar issue here with firebase attempting to serialize the result of the .getText().

Hope this helps others!

answered Oct 5, 2017 at 16:23

Rbar

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Comments

fraggjkee · Accepted Answer · 2016-08-02 13:01:43Z

16

I've managed to find the reason causing this crash. I installed the app on another device running Android 5.x and Firebase threw a much less confusing exception there:

com.google.firebase.database.DatabaseException: No properties to serialize found on class android.graphics.Paint$Align

It appeared that Firebase (unlike Gson) tries to serialize all possible getters even though they don't have direct connection with global variables (class members / fields), in my particular case one of my objects contained a method returning Drawable - getDrawable(). Obviously, Firebase doesn't know how to convert drawable into json.

Interesting moment (probably a bug in Firebase SDK): on my older device running Android 4.4.1 I still get my original exception in the same project and configuration:

Caused by: com.google.firebase.database.DatabaseException: Serializing Arrays is not supported, please use Lists instead

edited Aug 2, 2016 at 13:01

answered Aug 2, 2016 at 11:45

fraggjkee

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1 Comment

Anirudh Ganesh Over a year ago

In my case, I was getting data from an Editable field and was trying to push it directly. converting it toString() worked

Drew Holtzapfel · Accepted Answer · 2017-07-05 02:59:13Z

4

Add @Exclude to the functions that FB tries to interpret, like those that return a Drawable.

@Exclude
public Drawable getUnitColorImage(){
    return TextDrawable.builder().buildRound("", prefColor);
}

answered Jul 5, 2017 at 2:59

Drew Holtzapfel

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Comments

Entreco · Accepted Answer · 2017-05-11 06:29:33Z

2

Add @IgnoreExtraProperties to your class

@IgnoreExtraProperties
public class YourPojo {
    public String name;

    // Default constructor for Firebase
    public YourPojo(){} 

    // Normal constructor
    public YourPojo(String name) {
        this.name = name;   
    }
}

answered May 11, 2017 at 6:29

Entreco

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Comments

Rene Enriquez · Accepted Answer · 2016-09-15 17:35:03Z

1

I had a similar problem, I was trying to use groovy instead of Java, I guess that groovy is generating other get methods for me. I converted my domain class from Pogo (src/main/groovy) to Pojo (src/main/java) and now all is working well

answered Sep 15, 2016 at 17:35

Rene Enriquez

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Tamir Abutbul · Accepted Answer · 2019-03-11 12:53:53Z

//this will recreate your Object list by the constructor


private void handleData(){ 

    orderList = Db.getCarts();
    orders = new ArrayList<>();
    Double totalPrice = 0.0;

    for (Order order : orderList){
        // totalPrice = totalPrice + ( price * quantity )
        totalPrice += (Double.valueOf(order.getPrice())* Integer.valueOf(order.getQuantity()));
        orders.add(new Order(order.getProductId(),order.getProductName(),order.getQuantity(),order.getPrice(),order.getDiscount(),order.getImage()));
    }
}

 private void alertDialog() {

    AlertDialog.Builder alert = new AlertDialog.Builder(getContext());
    alert.setTitle("One more step!");
    alert.setMessage("Enter your address");

    final EditText edtaddress = new EditText(getContext());
    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
            LinearLayout.LayoutParams.MATCH_PARENT,
            LinearLayout.LayoutParams.MATCH_PARENT
    );

    edtaddress.setLayoutParams(layoutParams);
    alert.setView(edtaddress);
    alert.setIcon(R.drawable.ic_shopping_cart_black_24dp);

    alert.setPositiveButton("YES", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            Request request = new Request(
                    Common.currentUser.getPhone(),
                    Common.currentUser.getName(),
                    edtaddress.getText().toString(),
                    textTotal.getText().toString(),
                    orders
            );

            // Submit to firebase
            // We will using system.currentMillis to key
            requestReference.child(String.valueOf(System.currentTimeMillis()))
                    .setValue(request);
            //Delete cart
            Db.deleteCart();
            Toast.makeText(getContext(), "Thank you , Order Place", Toast.LENGTH_SHORT).show();
            getActivity().finish();
        }
    });

    alert.setNegativeButton("No", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });

    alert.show();

}

Vijay · Accepted Answer · 2017-09-04 02:59:52Z

0

Here's how this was resolved for me. The issue occurred when I was trying to update an int field in database. I was getting text from edit text field and forgot to convert that into an int. This caused the failure. So try checking the data type you're sending to the database if this issue occurs.

answered Sep 4, 2017 at 2:59

Vijay

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Comments

Aman Thakur · Accepted Answer · 2021-04-25 20:33:48Z

0

When you use hashmap to set values use this to get url of image you're uploading.

task.getResult().getDownloadUrl().toString()

answered Apr 25, 2021 at 20:33

Aman Thakur

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