Android Firebase

Question

I'm trying to fetch firebase database data into a list, i get "com.google.firebase.database.DatabaseException: Failed to convert value of type java.lang.Long to String" or nullpointerexception at Products product = ds.getValue(Products.class);

public class Products {

private String id;
private String reccomended;

public Products(){}

public Products(String id, String reccomended){
    this.id = id;
    this.reccomended = reccomended;
}

public String getId() {return id;}

public void setId(String id) {this.id = id;}

public String getReccomended() {return reccomended;}

public void setReccomended(String reccomended) {this.reccomended = reccomended;}
}

Listener (locationSelected is location (currently "1" or "2") passed from another activity loaded from spinner)

dbRef.child(locationSelected).child("products").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot ds : dataSnapshot.getChildren()){
                Products product = ds.getValue(Products.class);
                list.add(product);
            }
            for (int i=0; i<list.size(); i++){
                Log.d("LIST: ", list.get(i).toString());
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

for example:

Log.d("LOG: ", ds.getValue().toString());

gives this output:

D/LOG:: {reccomended=7, id=502100}
D/LOG:: {reccomended=10, id=502267}
D/LOG:: {reccomended=15, id=502291}

Answer 1

You can Override toString method as per your requirement in your model class.

public String toString(){
return "{reccomended = "+this.reccomended+ ", id =" + this.id +"}"; 
}

Answer 2

Try using numeric data types for numeric data:

public class Products {

    private Long id;
    private Integer reccomended;
    //...

Seems like Firebase wants to convert your ID to long based on the content rather than String.