BarInsta/app/src/main/java/awais/instagrabber/customviews/helpers/GridSpacingItemDecoration.java

package awais.instagrabber.customviews.helpers;

import android.graphics.Rect;
import android.view.View;

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

public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {
    private final int spacing;

    public GridSpacingItemDecoration(int spacing) {
        this.spacing = spacing;
    }

    @Override
    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        final RecyclerView.LayoutManager manager = parent.getLayoutManager();
        if (manager instanceof GridLayoutManager) {
            final int spanCount = ((GridLayoutManager) manager).getSpanCount();
            final int position = parent.getChildAdapterPosition(view);
            final int column = position % spanCount;

            outRect.left = column * spacing / spanCount;
            outRect.right = spacing - (column + 1) * spacing / spanCount;
            if (position < spanCount) outRect.top = spacing;
            outRect.bottom = spacing;
        }
    }
}