如何每秒使用 RecyclerView 刷新 Firebase 数据库数据

Question

I create an Android app and I store data in the Firebase database and I get it, but when the user adds something new the data it does not display in the app until the user out and enter again into the app

I try this

  @Override
protected void onRestart() {
    super.onRestart();
   adapter.notifyDataSetChanged();

}

*the user add the data by goes to another activity. I wanna refresh the data in any moment the data add without out the app and enter again. this is how I set the data to the adapter

DatabaseReference myRef = FirebaseDatabase.getInstance().getReference();
myRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

            if (dataSnapshot.exists()) {
                for (DataSnapshot ds : dataSnapshot.getChildren()) {

                    for (DataSnapshot d : ds.getChildren()) {
                        data.add(d.getValue(game.class));

                    }
                    adapter = new allAdapter(data);
                    rv.setAdapter(adapter);
                
                    allGamesAdapter.notifyDataSetChanged();

                }
            }
           
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
           
            Toast.makeText(MainActivity.this, "error", Toast.LENGTH_SHORT).show();

        }

Answer 1

I wanna refresh the data at any moment the data add without out the app and enter again.

You are looking for the real-time feature of the Firebase Realtime Database. To get updates in real-time, you should change the call to addListenerForSingleValueEvent() with addValueEventListener() . What you are doing now, you are getting the data only once, hence that behavior. For more info, please check the official documentation:

• https://firebase.google.com/docs/database/android/read-and-write#listen_for_value_events