I'm having some trouble with sending integer data with an intent. (android)

public class MainActivity extends AppCompatActivity {
    Button decrementButton;
    TextView intervalCountTextView;
    Button incrementButton;
    int intervalCount = 0;
    Button intervalButtonSetter;
    private int numberOfIntervals;
    private static final String TAG = "MainActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        decrementButton = findViewById(R.id.decrementButton);
        intervalCountTextView = findViewById(R.id.intervallCount);
        incrementButton = findViewById(R.id.incrementButton);
        intervalButtonSetter = findViewById(R.id.intervalButtonSetter);

        decrementButton.setVisibility(View.INVISIBLE);

        decrementButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                intervalCount--;
                intervalCountSetter();

            }
        });

        // make sure you can't decrement past zero

        incrementButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                intervalCount++;
                intervalCountSetter();
            }
        });

        intervalButtonSetter.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                sendDataToAdapter();
            }
        });
    }



    private void intervalCountSetter() {
        String intervalCountString = Integer.toString(intervalCount);
        intervalCountTextView.setText(intervalCountString);

        if (intervalCount > 0) {
            decrementButton.setVisibility(View.VISIBLE);
        } else {
            decrementButton.setVisibility(View.INVISIBLE);
        }
    }

    private void sendDataToAdapter() {
        String numberOfIntervalsString = intervalCountTextView.getText().toString();
        numberOfIntervals= Integer.parseInt(numberOfIntervalsString);
        Intent intent = new Intent(this, CustomAdapter.class);
        if (numberOfIntervals > 0) { intent.putExtra("Interval Count", numberOfIntervals);
            Log.d(TAG, "sendDataToAdapter: We have the numbers");
            Log.d(TAG, "sendDataToAdapter: " + numberOfIntervals);
        startTimeActivity();

        } else {
            Toast.makeText(this, "You have to have at least 1 interval.", Toast.LENGTH_LONG).show();
        }

    }

    private void startTimeActivity() {
        Intent intent = new Intent(this, TimeActivity.class);
        startActivity(intent);
            Log.d(TAG, "startTimeActivity: TimeActivity has been started" + numberOfIntervals);


    }
}

public class TimeActivity extends AppCompatActivity {

    public static final String TAG = TimeActivity.class.getSimpleName();
    private int numberOfIntervals;
    private ArrayList<Integer> WTV = new ArrayList<>();
    private ArrayList<Integer> WET = new ArrayList<>();
    private ArrayList<Integer> RTV = new ArrayList<>();
    private ArrayList<Integer> RET = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_time);
        Log.d(TAG, "onCreate: Started");

        //Intent intent = getIntent();
        //numberOfIntervals = intent.getIntExtra("Interval Count", 0);
        //Log.d(TAG, "" + numberOfIntervals);

        initializeViews();




    }

    private void initializeViews() {
        Log.d(TAG, "initializeViews: Preparing views");
        //Make sure they can change through the R.strings


        WTV.add(R.string.work_text_view);
        WET.add(R.string.default_time_value);
        RTV.add(R.string.rest_text_view);
        RET.add(R.string.default_time_value);

        initializeRecyclerView();
    }

    private void initializeRecyclerView() {
        Log.d(TAG, "initializeRecyclerView: Initialize RecyclerView");
        RecyclerView intervalRecyclerView = findViewById(R.id.intervalRecyclerView);
        CustomAdapter adapter = new CustomAdapter(this, WTV, WET, RTV, RET);
        intervalRecyclerView.setAdapter(adapter);
        intervalRecyclerView.setLayoutManager(new LinearLayoutManager(this));

    }
}

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder>  {






    private static final String TAG = "CustomAdapter";

    private ArrayList<Integer> mWorkTW = new ArrayList<>();
    private ArrayList<Integer> mWorkET = new ArrayList<>();
    private ArrayList<Integer> mRestTW = new ArrayList<>();
    private ArrayList<Integer> mRestET = new ArrayList<>();
    private Context mContext;
    private int numberOfIntervals;






    public CustomAdapter( Context context , ArrayList<Integer> mWorkTW, ArrayList<Integer> mWorkET, ArrayList<Integer> mRestTW, ArrayList<Integer> mRestET) {

        this.mWorkTW = mWorkTW;
        this.mWorkET = mWorkET;
        this.mRestTW = mRestTW;
        this.mRestET = mRestET;
        this.mContext = context;
    }





    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View customView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.time_row, viewGroup,false);
        ViewHolder holder = new ViewHolder(customView);
        return holder;

    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {
        Log.d(TAG, "onBindViewHolder: called");
        viewHolder.workTextView.setText(R.string.work_text_view);
        viewHolder.restTextView.setText(R.string.rest_text_view);
        viewHolder.workEditText.setHint(R.string.default_time_value);
        viewHolder.restEditText.setHint(R.string.default_time_value);
    }

    @Override
    public int getItemCount() {
        Intent intent = new Intent();
        numberOfIntervals = intent.getIntExtra("Interval Count", numberOfIntervals);
        Log.d(TAG, "" + numberOfIntervals);
        return numberOfIntervals;




    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        TextView workTextView;
        EditText workEditText;
        TextView restTextView;
        EditText restEditText;
        ConstraintLayout parentLayout;


        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            workTextView = itemView.findViewById(R.id.workTextView);
            workEditText = itemView.findViewById(R.id.workEditText);
            restTextView = itemView.findViewById(R.id.restTextView);
            restEditText = itemView.findViewById(R.id.restEditText);
            parentLayout = itemView.findViewById(R.id.parentLayout);



        }
    }







}