How can order adapter by datetime in Firebase

Question

I want order Firebase by datetime(userOrderDateTime) and appear that in adapter with this order.
Check my Firebase image

My code is (I try below but it isn't work):

ref.orderByChild("userOrderDateTime").addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {

                for (DataSnapshot dataSnapshot : snapshot.getChildren()) {
                    UserOrder userOrder = dataSnapshot.getValue(UserOrder.class);
                    list.add(userOrder);
                }

                adapter.notifyDataSetChanged();

                if (list.size() == 0) {
                    gifImageView.setVisibility(GifImageView.VISIBLE);
                    userOrderBlankText.setVisibility(View.VISIBLE);
                    btnDeleteUserOrderItems.setVisibility(Button.INVISIBLE);
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });

score 0 · Answer 1 · answered Feb 28 '21 at 10:53

As I see in your screenshot, your userOrderDateTime property is o type String, meaning that the order will always be lexicographically. To have a correct order, you should store in that field a timestamp value, rather than a String. To achieve that, please see my answer from the following post:

How to save the current date/time when I add new value to Firebase Realtime Database

Once you change the type of the field, your elements will be ordered correctly.

How can order adapter by datetime in Firebase

1 Answers1