database.DatabaseException: Can't convert object of type java.lang.String to type

Question

My Problem

      08-10 04:23:28.820 21501-21501/my.org.medicare.medicareapp E/AndroidRuntime: FATAL EXCEPTION: main                                                   


        

Answer 1

Most likely this is your problem, in your fetchData method:

private void fetchData(DataSnapshot dataSnapshot)
{
    spacecrafts.clear();
    //dataSnapshot.getChildren()
    for (DataSnapshot ds : dataSnapshot.getChildren()) //--> At this point, ds is an iterator of dataSnapshot; it will iterate the dataSnapshot's children. In this case, the first child's type is String, thus the first iteration of ds will have a type of String. 
    {
        System.out.println(ds.getValue());
        protest spacecraft=ds.getValue(protest.class); //--> at this point, you tried to assign a String to an Object with type "protest" by conversion. This is illegal, so it will throw an exception instead.
        spacecrafts.add(spacecraft);
    }
}

I hope this helps.

Answer 2

Your fetchData function already receives DataSnapshot as a child-node, but even here you still loop through the children which will effectively be looping through individual keys (name, contact, centre). You should simply call getValue on DataSnaphot without looping:

private void fetchData(DataSnapshot dataSnapshot)
    {
        spacecrafts.clear();        
        protest spacecraft=dataSnapshot.getValue(protest.class);
        spacecrafts.add(spacecraft);        
    }

I hope this helps.