Get The Array Elements Of The Last Node In Firebase Realtime Database With Android

As shown in the image below, I have a database 'table' called fridge that has a child called food. food is an array that can contain one or more elements. I want to access the last

Solution 1:

You could follow the docs and use the limitToLast() method. Keys in firebase are ordered alphabetically.

Solution 2:

You can try this to get the data:

mDatabase.child("fridge").child(fridgeId).child("food").addListenerForSingleValueEvent(
    newValueEventListener() {
        @OverridepublicvoidonDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshotpostSnapshot: dataSnapshot.getChildren()) {
                 String foodItem = postSnapshot.getValue();
                 foodList.add(foodItem);
            }
        }
    });

Solution 3:

First, create a list to store those values.

List<String> food  = newArrayList<>();

Retrieve the last stored food inside each fridge key

mDatabase.child("fridge").child(yourPushID).child("food").limitToLast(1).addValueEventListener(newValueEventListener() {
  @OverridepublicvoidonDataChange(DataSnapshot dataSnapshot) {

    for(DataSnapshot snapshot : dataSnapshot.getChildren()){
    String lastFood = snapshot.getValue(String.class);
    //Add your food to the list
      food.add(lastFood);
      Log.e("Foods found:",""+lastFood);

       }
  }

  @OverridepublicvoidonCancelled(DatabaseError databaseError) {
    System.out.println("The read failed: " + databaseError.getCode());
  }
});

Where yourPushID should be how you are generating those random keys to store your food

Where mDatabase is

DatabaseReference mDatabase;

mDatabase = FirebaseDatabase.getInstance().getReference();