arraylist - How to Retrieve a List object from the firebase in android

Question

I am having trouble retrieving a List from the Firebase. I have no trouble storing it, but as soon as I try to cast dataSnapshot.getValue() to ArrayList my app crashes, giving an exception:

HashMap cannot be casted to ArrayList

But when I tried to cast it to a HashMap, it also crashes, giving exception:

ArrayList can't be casted to hashmap

Need help please! Here is the code that is creating the problem:

Fire.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        List<TaskDes> td = (ArrayList<TaskDes>) dataSnapshot.getValue()
        notifyDataSetChanged();
    }

    @Override
    public void onCancelled(FirebaseError firebaseError) {

    }
});

I want to retrieve all the data in the Firebase as one List. The class TaskDes contains three fields:

class TaskDes { // definition
    boolean done
    String taskDescription
    String taskTitle
}

Answer 1

Waitting for answers