What Does ' Com.google.firebase.database.databaseexception: Serializing Arrays Is Not Supported, Please Use Lists Instead' Mean?

the main public class SignupCarrier extends AppCompatActivity { Button upProfile, upIDPhoto, upCriminalRecord, buttonSigningUp; private Uri mProfilePic, mIdPhoto,mCriminalRecord

Solution 1:

This is an array:

String[] pictureUrls = newString[picturesUrls.size()];

This is a list:

List<String> picturesUrls = newArrayList<String>();

The error message says you can't serialize arrays - so try changing the array to a list in the object you want to serialize (the CarrierUser).