Trouble when searching multiple data from mysql database in android

Question

I am building an app in which I have a view with multiple tabs. Each tab contains a RecyclerView which gets populated from data in MySQL. So there is the Activity with the ViewPager and then each tab has its own Fragment. So I use the Interface to pass data from Fragment to Activity in order to be able to search for. The thing is that if I do not scroll over the tabs the recycler List is null so I cannot search. My question is would it be better if I search directly in the database or is there any other way to do this?

My App looks like this:

The code for passing data is:

Interface:

public interface CoffeeCommunicator {
    void sendCoffeeListData(String name, String image, String price);
}

Fragment:

@Override
        protected List<ProductList> doInBackground(String... params) {
            try {
                url = new URL(params[0]);
                urlConnection =(HttpURLConnection) url.openConnection();
                urlConnection.connect();
                urlConnection.setConnectTimeout(5000);
                InputStream in = new BufferedInputStream(urlConnection.getInputStream());
                jsonResult = StringGenerator.inputStreamToString(in, getActivity());
                customList = new ArrayList<>();

                jsonResponse = new JSONObject(jsonResult.toString());
                jsonMainNode = jsonResponse.optJSONArray(AppConstant.COFFEE_JSON_ARRAY);
                for (int i = 0; i < jsonMainNode.length(); i++) {
                    jsonChildNode = jsonMainNode.getJSONObject(i);
                    name = jsonChildNode.optString("name");
                    price = jsonChildNode.optString("price");
                    image = jsonChildNode.optString("image");
                    customList.add(new ProductList(image, name, price));
                    coffeeCommunicator.sendCoffeeListData(name, image, price);

                }
            } catch (IOException | JSONException e) {
                e.printStackTrace();
            }
            return customList;
        }

@Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        coffeeCommunicator = (CoffeeCommunicator)activity;
    }

Activity:

@Override
    public void sendCoffeeListData(String name, String image, String price) {
        coffeesList.add(new ProductList(image, name, price));
    }

So then i have coffeeList available to search for.

Any ideas would be helpfull.

Answer 1

I can give code sample but you know your code better. Here's a sample:

In Activity:

populateList();

coffeeFragment = CoffeeFragment.newInstance();
coffeeFragment.setList(coffeesList);

void populateList() {
    jsonResponse = new JSONObject(jsonResult.toString());
    jsonMainNode = jsonResponse.optJSONArray(AppConstant.COFFEE_JSON_ARRAY);
    for (int i = 0; i < jsonMainNode.length(); i++) {
        jsonChildNode = jsonMainNode.getJSONObject(i);
        name = jsonChildNode.optString("name");
        price = jsonChildNode.optString("price");
        image = jsonChildNode.optString("image");
        coffeesList.add(new ProductList(image, name, price));
    }
}

Fragment:

public void setList(final List<ProductList> arrayList) {
{
    customList = arrayList;
}

Note: Basically you fill data onto coffeesList in Activity. And then pass the List onto the Fragment. I pass a List object by calling a method setList in the Fragment because it is easier.

I hope that is clear enough. Is there a problem with this approach?