hgultae / sectioned-recyclerview

Implement a multi-sectioned RecyclerView using a custom adapter interface.

Sectioned RecyclerView

Sectioned RecyclerView allows you to easily split a RecyclerView into sections with headers.

---

Gradle Dependency

The Gradle dependency is available via jCenter. jCenter is the default Maven repository used by Android Studio.

Dependency

Add this to your module's build.gradle file:

dependencies {
    // ... other dependencies
    compile 'com.afollestad:sectioned-recyclerview:0.2.3'
}

Adapter

Here's a basic example:

public class MainAdapter extends SectionedRecyclerViewAdapter<MainAdapter.MainVH> {

    @Override
    public int getSectionCount() {
        return 20; // number of sections.
    }

    @Override
    public int getItemCount(int section) {
        return 8; // number of items in section (section index is parameter).
    }

    @Override
    public void onBindHeaderViewHolder(MainVH holder, int section) {
        // Setup header view.
    }

    @Override
    public void onBindViewHolder(MainVH holder, int section, int relativePosition, int absolutePosition) {
        // Setup non-header view.
        // 'section' is section index.
        // 'relativePosition' is index in this section.
        // 'absolutePosition' is index out of all non-header items.
        // See sample project for a visual of how these indices work.
    }

    @Override
    public MainVH onCreateViewHolder(ViewGroup parent, int viewType) {
        // Change inflated layout based on 'header'. 
        View v = LayoutInflater.from(parent.getContext())
                .inflate(viewType == VIEW_TYPE_HEADER ? R.layout.header : R.layout.normal, parent, false);
        return new MainVH(v);
    }

    public static class MainVH extends RecyclerView.ViewHolder {

        public MainVH(View itemView) {
            super(itemView);
            // Setup view holder.
            // You'd want some views to be optional, e.g. for header vs. normal.
        }
    }
}

Layout Manager

If you're using a LinearLayoutManager, you're all set. If you're using a GridLayoutManager, you need to tell the adapter:

GridLayoutManager manager = // ...
adapter.setLayoutManager(manager);

This is vital to getting headers to span all columns.