Can't convert object of type java.lang.Long to type

Question

I'm trying to connect my app to a Firebase Database, but whenever I launch the code that problem show up

that's my main activity

public class MainActivity extends AppCompatActivity {






    private static final String TAG = "ViewDatabase";

    private FirebaseDatabase mFirebaseDatabase;
    private DatabaseReference myRef;
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mFirebaseDatabase = FirebaseDatabase.getInstance();
    myRef = mFirebaseDatabase.getReference("Discount/Business");



    myRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for(DataSnapshot ds : dataSnapshot.getChildren()){
                UserInformation uInfo = new UserInformation();
                uInfo.setAltro(ds.child("Altro").getValue(UserInformation.class).getAltro());
                uInfo.setCognome(ds.child("Cognome").getValue(UserInformation.class).getCognome());
                uInfo.setInformazioni(ds.child("Informazioni").getValue(UserInformation.class).getInformazioni());
                uInfo.setNome(ds.child("Nome").getValue(UserInformation.class).getNome());


                Log.d(TAG, "showData: Altro: " + uInfo.getAltro());
                Log.d(TAG, "showData: Cognome: " + uInfo.getCognome());
                Log.d(TAG, "showData: Informazioni: " + uInfo.getInformazioni());
                Log.d(TAG, "showData: Nome: " + uInfo.getNome());





            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

}

that's my User class

public class UserInformation {
private String Altro;
private String Cognome;
private String Informazioni;
private String Nome;



public UserInformation(){

}

public String getAltro() {
    return Altro;
}

public void setAltro(String altro) {
    Altro = altro;
}

public String getCognome() {
    return Cognome;
}

public void setCognome(String cognome) {
    Cognome = cognome;
}

public String getInformazioni() {
    return Informazioni;
}

public void setInformazioni(String informazioni) {
    Informazioni = informazioni;
}


public String getNome() {
    return Nome;
}

public void setNome(String nome) {
    Nome = nome;
}

My firebase database

and my log error

11-14 10:59:55.016 2909-2909/com.app8 E/AndroidRuntime: FATAL EXCEPTION: main
                                                        Process: com.app8, PID: 2909
                                                        com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.Long to type com.app8.UserInformation
                                                            at com.google.android.gms.internal.zzbqi.zze(Unknown Source)
                                                            at com.google.android.gms.internal.zzbqi.zzb(Unknown Source)
                                                            at com.google.android.gms.internal.zzbqi.zza(Unknown Source)
                                                            at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
                                                            at com.app8.MainActivity$1.onDataChange(MainActivity.java:41)
                                                            at com.google.android.gms.internal.zzbmz.zza(Unknown Source)
                                                            at com.google.android.gms.internal.zzbnz.zzYj(Unknown Source)
                                                            at com.google.android.gms.internal.zzboc$1.run(Unknown Source)
                                                            at android.os.Handler.handleCallback(Handler.java:751)
                                                            at android.os.Handler.dispatchMessage(Handler.java:95)
                                                            at android.os.Looper.loop(Looper.java:154)
                                                            at android.app.ActivityThread.main(ActivityThread.java:6119)
                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

It's my first time using Firebase, I've seen other questions related to the topic but I can't figure out how to make it works, I hope you can help me.

thanks for your help, any suggestion is highly appreciated

Answer 1

I figured out the actual reason of this error. This issue occurred to me also just now. What I came to know was there was some sort of garbage data collection occurred in the firebase database.

Solution : Open Firebase console -> Go to Database -> Delete all the database data -> Uninstall app from phone -> Reinstall -> Error Solved !!

Happy Coding!

Answer 2

To get those values out from the database, please use the following code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference businessRef = rootRef.child("Discount").child("Business");
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String altro = ds.child("Altro").getValue(String.class);
            String cognome = ds.child("Cognome").getValue(String.class);
            String informazioni = ds.child("Informazioni").getValue(String.class);
            String nome = ds.child("Nome").getValue(String.class);
            Log.d("TAG", altro + " / " + cognome + " / " + informazioni + " / " + nome);
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
businessRef.addListenerForSingleValueEvent(eventListener);

As an advice, use in the future all fields according cu Java Naming Conventions.

Answer 3

Can you try below.

UserInformation uiFromSnapShot = ds.getValue(UserInformation.class); uInfo.setXXX(uiFromSnapShot.getXXX);