How to create RecyclerView with multiple view types

java

data-binding

view-holder-pattern

recyclerview

byNikita Barsukov·Nov 4, 2024

To construct a multi-view RecyclerView, first identify unique view types in getItemViewType(). Then, inflate custom layouts in onCreateViewHolder() tailored to each view's content. Lastly, use onBindViewHolder() to populate every layout, switching on the view types.

class MultiViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    // Define your crowd favorite view types
    private static final int TEXT_ITEM_VIEW_TYPE = 0; // Plain text: The Shakespeare of view types
    private static final int IMAGE_ITEM_VIEW_TYPE = 1; // A picture speaks a thousand words, they said. 

    // Time to party, but check the guest list
    @Override
    public int getItemViewType(int position) {
        return isPositionForTextItem(position) ? TEXT_ITEM_VIEW_TYPE : IMAGE_ITEM_VIEW_TYPE;
    }

    // Inflate the party venue
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view;
        if (viewType == TEXT_ITEM_VIEW_TYPE) {
            view = LayoutInflater.from(parent.getContext()).inflate(R.layout.text_item, parent, false);
            return new TextViewHolder(view);
        } else {
            view = LayoutInflater.from(parent.getContext()).inflate(R.layout.image_item, parent, false);
            return new ImageViewHolder(view);
        }
    }

    // "Check, check. Microphone check." - Your friendly onBindViewHolder
    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (getItemViewType(position) == TEXT_ITEM_VIEW_TYPE) {
            ((TextViewHolder)holder).bindTextItem(/* Shakespeare texts for this position */);
        } else {
            ((ImageViewHolder)holder).bindImageItem(/* A thousand words for this position */);
        }
    }

    // To be text, or not to be text, that is the question
    private boolean isPositionForTextItem(int position) {
        // Your logic: Wisdom from centuries of boolean evaluation
    }

    // Descendant of the mighty ViewHolder, Knight of Texts
    static class TextViewHolder extends RecyclerView.ViewHolder {
        // Get your swords...err...text views ready
        TextViewHolder(View itemView) {
            super(itemView);
            // Your text view holders bravely marching to war
        }
        
        // Battle tactics for text
        void bindTextItem(/* Your text data type */ textData) {
            // Bridle the words, my Lord
        }
    }

    // Descendant of the mighty ViewHolder, Knight of Images
    static class ImageViewHolder extends RecyclerView.ViewHolder {
        // Get your shields...err...image views ready
        ImageViewHolder(View itemView) {
            super(itemView);
            // Your image view holders locking their shields
        }

        // Battle tactics for images
        void bindImageItem(/* Your image data type */ imageData) {
            // Unleash the artistry, my Lord
        }
    }
}

Make your list wielding multi-layouts efficient by isolating view within its own fortress (view holder), ensuring modularity and readability.

Building an impressive adapter

Inflating dynamic views

Your RecyclerView may need to dynamically inflate layouts based on changes in data or user interaction. Naïvely calling notifyDataSetChanged() or the more granular methods like notifyItemChanged(), notifyItemInserted(), may lead to issues. Address this by maintaining a list of items within your adapter, ensuring stability and smooth UI behavior.

Harnessing a legion of items

By subclassing BaseItem for different view types, you can maintain a versatile and clear management of your data. When coupled with DataBindAdapter, managing your views becomes a cakewalk, even for complex lists and data binding.

Interactive fights with your items

When you have interactive elements like buttons in your RecyclerView, implement click listeners in your ViewHolder classes. This strategy keeps the corresponding actions within the view holder's premises, without cluttering the adapter's logic. Cleanliness is armor, after all.

Decoding your view types

Assigning constant identifiers to each view type enhances code clarity and maintainability. Ladies and Gentlemen, presenting to you the best-dressed code in town! Easy to understand and even easier to revisit!

Allies in third-party libraries

Why trouble when we can delegate? Useful third-party libraries are your powerful allies that offer more sophisticated solutions. Drop your anchor at the "RecyclerView-MultipleViewTypesAdapter" repository in GitHub. It has ready examples specifically for handling multiple view types with headers, footers, and sections.

Visualization

Visualize a RecyclerView with multiple view types as a tray. A tray with different compartments, much like the one in school cafeterias:

🍽️ = RecyclerView
| Type 1 | Type 2 | Type 3 |
|:------:|:------:|:------:|
| 🍌 Fruits | 🍚 Rice | 🍖 Meat |

Each compartment is a view type:

🍽️ ------> [🍌] ------> [🍚] ------> [🍖]
# The RecyclerView "tray" serving different "dishes" in respective "compartments".

A Custom Adapter is the efficient lunch lady:

🍛🧍‍♀️
"Serving you, your choice of meal. 🥘 Decide which 'dish' goes into which 'compartment'."

Isn't that palatable?

Fine tuning your RecyclerView

Embrace data changes

Ever heard of the constant change? It applies to your data sets as well. With multiple view types, handling data changes is a top priority. Bear in mind that a good adapter not only manages the quantity of data but also the types of views required to represent them accurately.

Unleash the power of ViewHolder Pattern

The ViewHolder pattern is more than a fashion statement. It's the very backbone of smooth scrolling and performance of your RecyclerView. Each ViewHolder class dresses its layout elements perfectly without new object lookups or object creations, offering you an efficient and flexible list.

Bind Data Respectfully

If you use Android's Data Binding library, you're in a treat! Your views can be bound directly in XML, reducing your adapter's and view holders' weight. Just ensure the extension from RecyclerView.ViewHolder and correct initialisation in your binding class.

Error Handling Mastery

Like any master swordsmen, be vigilant and proactive about possible errors — view type mismatches or data inconsistency. Good logging and handling these within the adapter prevent anomalies and aid debugging. Remember, "debugging is like being the detective in a crime movie where you are also the murderer." (- Filipe Fortes)

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