AbsolutefitLayoutManager.java

import android.content.Context;

import android.util.AttributeSet;
import android.view.ViewGroup;

import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

public class AbsolutefitLayourManager extends GridLayoutManager {

    // column count for orientation = HORIZONTAL
    private static final int spanColumnCount = 2;
    public AbsolutefitLayourManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public AbsolutefitLayourManager(Context context, int spanCount) {
        super(context, spanCount);
    }

    public AbsolutefitLayourManager(Context context, int spanCount, int orientation, boolean reverseLayout) {
        super(context, spanCount, orientation, reverseLayout);
    }


    /* Setting LayoutParams for the child views of the recycler view.*/
    @Override
    public RecyclerView.LayoutParams generateDefaultLayoutParams() {
        return spanLayoutSize(super.generateDefaultLayoutParams());
    }

    @Override
    public RecyclerView.LayoutParams generateLayoutParams(Context c, AttributeSet attrs) {
        return spanLayoutSize(super.generateLayoutParams(c, attrs));
    }

    @Override
    public RecyclerView.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
        return spanLayoutSize(super.generateLayoutParams(lp));
    }

    /* The function has been made for Horizontal Recycler View.
     *  1. It checks for the orientation to be HORIZONTAL.
     *  2. Its spancount has already been set to 2 in this case throught the constuctor at the initialisation time.
     *    i.e,  layoutManager = new AbsolutefitLayourManager(this,2,GridLayoutManager.HORIZONTAL,false);
     *    the spancount = 2 , specifies the no. of rows for HORIZONTAL orientation
     * 3. The rest of the function divides the horizontal screen width by 2 (spanColumnCount = 2 HERE) hence specyfing the column
          width of each view and hence specifying  2 columns (can be made 3, by dividing by three.)
     */
    private RecyclerView.LayoutParams spanLayoutSize(RecyclerView.LayoutParams layoutParams){
        if(getOrientation() == HORIZONTAL){
            layoutParams.width = (int) Math.round( getHorizontalSpace() / spanColumnCount);
            // its the margin between the items
            layoutParams.setMargins(2,2,2,2);
        }
//        else if(getOrientation() == VERTICAL){
//            layoutParams.height = (int) Math.round(getVerticalSpace() /  spanCount);
//        }
        return layoutParams;
    }

    @Override
    public boolean checkLayoutParams(RecyclerView.LayoutParams lp) {
        return super.checkLayoutParams(lp);
    }

    private int getHorizontalSpace() {
        return getWidth() - (getPaddingRight()) - (getPaddingLeft()) ;
    }

    private int getVerticalSpace() {
        return getHeight() - getPaddingBottom() - getPaddingTop();
    }