Call multiple JsonHttpResponseHandler but only one onFinish

Question

I created a layout in my app where I have multiple checkboxes and once the user checked some and clicks ok, I search it via a jsonHttpResponse (each iteration is an item that was checked):

for (int i = 0; i < items.size(); i++) {
    String itemID = items.get( i ).getitemID();

    MyitemClient client = new MyitemClient();
    client.getitems( itemID, new JsonHttpResponseHandler() {
        @Override
        public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
            if (response != null) {
                final Myitem items = Myitem.fromJson( response );
                itemNames = itemNames + items.getTitle() + "\n";
            }
        }

        @Override
        public void onFinish() {
            String TimeFormat = "dd.MM.yyyy";
            SimpleDateFormat df2 = new SimpleDateFormat( TimeFormat );
            String dateText = df2.format( dateInMillis );

            db = FirebaseFirestore.getInstance();
            CollectionReference usernamedb = db.collection( "Users" ).document( auth.getUid() ).collection( "UserData" );
            usernamedb.get().addOnCompleteListener( task -> {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        String NewMessage = document.getString( "username" ) + " wants these items: \n\n" + itemNames + "\nUntil " + dateText + "\n\nDo you confirm?";
                        chatOrganizer.addMessageToChat( chatID, auth.getUid(), receiverID, NewMessage, true );

                    }
                }

            } );
        }
    } );

}

and the client is:

public class MyitemClient {

    private static final String API_BASE_URL = "https://www.somesiteinhere..../";
    private AsyncHttpClient client;

    public MyitemClient() {
        this.client = new AsyncHttpClient();
    }

    public void getitems(final String query, JsonHttpResponseHandler handler) {
        try {
            client.get(API_BASE_URL + URLEncoder.encode(query, "utf-8"), handler);
        } catch (UnsupportedEncodingException ignored) {

        }
    }

}

My goal is to get from that client the itemTitle and once all of the titles were obtained, to launch a message as shown in chatOrganizer.

My problem is that in this implementation it enters to onFinish as many times as the iteration and therefore it prints this message for every item.

How can I make sure that it will enter onFinish only once all of the iterations are finished?

Thank you

Answer 1

I think one solution can be that:

• You write two handlers, one with dummy onFinish (the method does nothing) and one with your current implementation onFinish.
• Check the index of i. If i is not the last item, pass the dummy handler to client.getitems as the second parameter. If i is the last item, pass the other to client.getItems(...).

i hope that this idea is helpful =)

if (i != items.size() -1) {
  client.getItems (itemID, new JsonHttpResponseHandler(){
        @Override
        public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
            if (response != null) {
                final Myitem items = Myitem.fromJson( response );
                itemNames = itemNames + items.getTitle() + "\n";
                //TODO save item names
            }
        }
        @Override
        public void onFinish(int statusCode, Header[] headers, JSONObject response) {
            //DO nothing
        }
  })
} else {
  client.getItems (itemID, new JsonHttpResponseHandler(){
        @Override
        public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
            if (response != null) {
                final Myitem items = Myitem.fromJson( response );
                itemNames = itemNames + items.getTitle() + "\n";
                //TODO save item names
            }
        }
        @Override
        public void onFinish(int statusCode, Header[] headers, JSONObject response) {
            String TimeFormat = "dd.MM.yyyy";
            SimpleDateFormat df2 = new SimpleDateFormat( TimeFormat );
            String dateText = df2.format( dateInMillis );

            db = FirebaseFirestore.getInstance();
            CollectionReference usernamedb = db.collection( "Users" ).document( auth.getUid() ).collection( "UserData" );
            ...
        }
  })
}