Generic RecyclerView adapter

Generic RecyclerView Adapter.

Lightweight library which simplifies creating RecyclerView adapters and illuminates writing boilerplate code.

Creating adapters is as easy as never before, just follow the steps below:

1. Add dependency to your build.gradle (app-level).

dependencies {
    implementation "com.leodroidcoder:generic-adapter:1.0.1"
}

2. Create a ViewHolder:

public class UserViewHolder extends BaseViewHolder<User, OnRecyclerItemClickListener> {

    private TextView nameTv;

    public UserViewHolder(View itemView, OnRecyclerItemClickListener listener) {
        super(itemView, listener);
        // initialize view and set click listener
        nameTv = itemView.findViewById(R.id.tv_name);
        if (listener != null) {
                    itemView.setOnClickListener(v -> listener.onItemClick(getAdapterPosition()));
                }
    }

    @Override
    public void onBind(User item) {
        // bind data to the views
        nameTv.setText(item.getName());
    }
}

Or in Kotlin:

class UserViewHolder(itemView: View, listener: OnRecyclerItemClickListener?) : BaseViewHolder<User, OnRecyclerItemClickListener>(itemView, listener) {

    private val nameTv: TextView? = itemView.tv_name

    init {
        listener?.run {
            itemView.setOnClickListener { onItemClick(adapterPosition) }
        }
    }

    override fun onBind(item: User) {
        nameTv?.text = item.name
    }
}

3. Create an Adapter:

public class SimpleAdapter extends GenericRecyclerViewAdapter<User, OnRecyclerItemClickListener, UserViewHolder> {

    public SimpleAdapter(Context context, OnRecyclerItemClickListener listener) {
        super(context, listener);
    }

    @Override
    public UserViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new UserViewHolder(inflate(R.layout.item_user, parent), getListener());
    }
}

Or in Kotlin:

class SimpleAdapter(context: Context, listener: OnRecyclerItemClickListener) : GenericRecyclerViewAdapter<User, OnRecyclerItemClickListener, UserViewHolder>(context, listener) {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): UserViewHolder {
        return UserViewHolder(inflate(R.layout.item_user, parent), listener)
    }
}

That's it!!

Just use it as a regular adapter in your Fragment or Activity:

public class YourFragment extends Fragment implements OnRecyclerItemClickListener {

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        // ...
        // instantiate the adapter and set it onto a RecyclerView
        SimpleAdapter adapter = new SimpleAdapter(getActivity(), this);
        recyclerView.setAdapter(adapter);

        // populate adapter with data when it is ready
        List<User> users = getYourUsers();
        adapter.setItems(users);
    }

    /**
     * This is a callback of the recycler listener.
     * {@link OnRecyclerItemClickListener}.
     * Is being triggered when an item has been clicked.
     *
     * @param position clicked position
     */
    @Override
    public void onItemClick(int position) {
        // get the User entity, associated with the clicked item.
        final User clickedUser = adapter.getItem(position);
        // do whatever you want with it
    }
}

Simplifies creating:

• Regular adapters
• Adapters with multiple ViewTypes
• with multiple listeners per item
• with DiffUtil

Checkout complete samples, including all these use cases.

Or read an article with the detailed explanation:

https://medium.com/@leo.droidcoder/recyclerview-adapter-a-piece-of-cake-with-the-generic-adapter-766cedffd81

Enjoy!