Generic 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!