What to do if AS asks to change the type of a variable from an integer to an array?

Question

Java

I am writing code for a fragment, creating a messageCount variable and assigning a value to it (I do this through FirebaseDatabase, because I took the value from there, but an error was thrown and I decided to try just assigning 1), and suddenly an error occurs that you need to turn an integer into array. I tried to move the variable outside the onCreateView() event, but the application just crashed there.

Here's the whole code:
PS - don't pay attention to the unused bits of code in the form of the Message class and something else.

package com.neura.neuramessanger;

import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ScrollView;
import android.widget.TextView;
import android.widget.Toast;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link GeneralChat#newInstance} factory method to
 * create an instance of this fragment.
 */
public class GeneralChat extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    public GeneralChat() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment GeneralChat.
     */
    // TODO: Rename and change types and number of parameters
    public static GeneralChat newInstance(String param1, String param2) {
        GeneralChat fragment = new GeneralChat();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            // TODO: Rename and change types of parameters
            String mParam1 = getArguments().getString(ARG_PARAM1);
            String mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_general_chat, container, false);
        Button send = view.findViewById(R.id.send_message_to_general_chat);
        EditText inputArea = view.findViewById(R.id.message_input_area);
        ScrollView chatView = view.findViewById(R.id.chatView);
        send.setOnClickListener(v -> {
            final int messageCount;
            FirebaseDatabase.getInstance().getReference().addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot snapshot) {
                    messageCount = 1;
                }

               @Override
                public void onCancelled(@NonNull DatabaseError error) {
                    Toast.makeText(getActivity(), "Error:" + error.getMessage(), Toast.LENGTH_SHORT).show();
                }
            });
//            Toast.makeText(getActivity(), messageCount, Toast.LENGTH_SHORT).show();
            TextView message = new TextView(getActivity());
            message.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
            String messageText = inputArea.getText().toString().trim();
            message.setText(messageCount);
            chatView.addView(message);
            inputArea.setText(null);
        });
        return view;
    }

    public static class Message {
        public final Integer messageCount;

        public Message(Integer messageCount) { this.messageCount = messageCount; }
    }
}

Answer 1

This is because in Java lambdas can capture read-only variables, you cannot change local variables from a lambda. Therefore, the studio offers you a "hack". Turn the variable into an array with one element, and modify that element. This is a well-known trick.