Recyclerview from parcelable arraylist

Question

I have an arraylist of custom objects nested inside another arraylist like this:

public class Person implements Parcelable {
private String Name;
private float Age;
private String Email;
ArrayList<Hobbies> Hobbies;


public Person(String name, float age, String email, ArrayList<Hobbies> hobbies) {
    this.Name = name;
    Age = age;
    this.Email = email;
    this.Hobbies = hobbies;
}

I pass this arraylist from MainActivity to another activity using 'putParcelableArrayListExtra()'

intent.putParcelableArrayListExtra(HOBBIES_ARRAY, Person.get(position).getHobbies());

I use this to retrieve it

hobbiesArray = new Arraylist<>();
hobbiesArray = getIntent().getParcelableArrayListExtra(MainActivity.HOBBIES_ARRAY);

I then add this list to recyclerview

hobbiesRecycler = findViewById(R.id.HobbyRecycler);
mLayoutManager = new LinearLayoutManager(this);
adapter = new HobbiesAdapter(hobbiesArray);
hobbiesRecycler.setLayoutManager(mLayoutManager);
hobbiesRecycler.setAdapter(adapter);
adapter.notifyDataSetChanged();

This is the error i'm getting: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.util.ArrayList.size()' on a null object reference at com.example.ReminderApp.hobbiesAdapter.getItemCount(hobbiesAdapter.java:55)

Edit: I'm also adding items to the arraylist from the second activity

Answer 1

Are Hobbies Parcelable too? From the code you have shown, The class Person is parcelable So that can be sent.

You can use http://www.parcelabler.com/ to ensure all the methods required are set.

Try sending Person and then retrieving the Hobbies from the Person class.

Answer 2

Add null check to your getItemsCount function in Adapter.

 .... getItemsCount(){
     returm yourList != null ? yourList.size() : 0;
}