Flexbox inside the RecyclerView as a LayoutManager (FlexboxLayoutManager).

Currently google has release the Flexbox which can be used for building flexible layouts using FlexboxLayout, it can be interpreted as an advanced LinearLayout because both layouts align their child views sequentially.
For more detail on this flexbox-layout

But here we are gonna work on Flexbox with RecyclerView. Flexbox with a large number of items in a scrollable container!

Let's first see what are the Supported attributes / features comparison

Due to some characteristics of the RecyclerView, some Flexbox attributes are not available/not implemented to the FlexboxLayoutManager. Here is a quick overview of the attributes/features comparison between the two containers.

Attribute / Feature

	FlexboxLayout	FlexboxLayoutManager (RecyclerView)
flexDirection
flexWrap		(except wrap_reverse)
justifyContent
alignItems
alignContent		-
layout_order		-
layout_flexGrow
layout_flexShrink
layout_alignSelf
layout_flexBasisPercent
layout_(min/max)Width
layout_(min/max)Height
layout_wrapBefore
Divider
View recycling	-
Scrolling	*1

*1 Partially possible by wrapping it with ScrollView. But it isn't likely to work with large set of views inside the layout. Because it doesn't consider view recycling.

Setting Flexbox attributes through Java code instead of settings those from XML for the FlexboxLayoutManager For example:

Add the following dependency to your build.gradle file:
dependencies {
       compile 'com.google.android:flexbox:0.3.0-alpha3'
}

layout.xml is gonna be same as we do for normal recyclerview. only through java code we will use flexbox.

In Activity:

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
FlexboxLayoutManager layoutManager = new FlexboxLayoutManager();
layoutManager.setFlexWrap(FlexWrap.WRAP);
layoutManager.setFlexDirection(FlexDirection.ROW);
layoutManager.setAlignItems(AlignItems.STRETCH);
recyclerView.setLayoutManager(layoutManager);
RecyclerView.Adapter adapter = new CatAdapter(this);
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();

Create a CatAdapter:

public class CatAdapter extends RecyclerView.Adapter<CatViewHolder>{
    private static final int[] CAT_IMAGE_IDS = new int[]{
            R.drawable.cat_1,R.drawable.cat_2,R.drawable.cat_3};
    private Context mContext;
    CatAdapter(Context context){
        mContext = context;    
    }

    @Override    
    public CatViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.main_activity, parent, false);        
        return new CatViewHolder(view);    
    }

    @Override    
    public void onBindViewHolder(CatViewHolder holder, int position) {
        int pos = position % CAT_IMAGE_IDS.length;        
        Drawable drawable = ResourcesCompat.getDrawable(mContext.getResources(),                
        CAT_IMAGE_IDS[pos], null);        
        holder.bindTo(drawable);    
    }

    @Override    
    public int getItemCount() {
        return CAT_IMAGE_IDS.length * 4;    
    }

}

Create a CatViewHolder:

public class CatViewHolder extends RecyclerView.ViewHolder {

    private ImageView mImageView;
    CatViewHolder(View itemView) {
        super(itemView);        
        mImageView = (ImageView) itemView.findViewById(R.id.icon_view);    
    }

    void bindTo(Drawable drawable) {
        mImageView.setImageDrawable(drawable);        
        ViewGroup.LayoutParams lp = mImageView.getLayoutParams();        
        if (lp instanceof FlexboxLayoutManager.LayoutParams) {
            FlexboxLayoutManager.LayoutParams flexboxLp = (FlexboxLayoutManager.LayoutParams)lp;            
            flexboxLp.setFlexGrow(1.0f);        }
    }
}

For more details on this demo-cat-gallery