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import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
 * Created by Android Studio
 * User: Ailurus(ailurus@foxmail.com)
 * Date: 2015-10-28
 * Time: 15:20
 */
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {

    private int spanCount;
    private int spacing;
    private boolean includeEdge;
    private int headerNum;

    public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge, int headerNum) {
        this.spanCount = spanCount;
        this.spacing = spacing;
        this.includeEdge = includeEdge;
        this.headerNum = headerNum;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int position = parent.getChildAdapterPosition(view) - headerNum; // item position

        if (position >= 0) {
            int column = position % spanCount; // item column

            if (includeEdge) {
                outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
                outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)

                if (position < spanCount) { // top edge
                    outRect.top = spacing;
                }
                outRect.bottom = spacing; // item bottom
            } else {
                outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
                outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f /    spanCount) * spacing)
                if (position >= spanCount) {
                    outRect.top = spacing; // item top
                }
            }
        } else {
            outRect.left = 0;
            outRect.right = 0;
            outRect.top = 0;
            outRect.bottom = 0;
        }
    }
    }
}

If you want to use it, just do as the following.

int spacingInPixels = getResources().getDimensionPixelSize(R.dimen.grid_layout_margin);
recyclerView.addItemDecoration(new GridSpacingItemDecoration(2, spacingInPixels, true, 0));

wogenhaosini commented on 6 Dec 2016

Thank you very much。

WMTAndroidJaymin commented on 2 Jan

Thanks...

ravigajadin commented on 6 Jan

thanks

eltray commented on 25 Jan

Perfect! Thanks man.

Fomovet commented on 21 Jun

Thank you very much! You are my brother

burakkarabonial commented on 16 Aug

Great, thanks!

tatocaster commented on 11 Sep

just a converted into Kotlin

class GridSpacingItemDecoration(private val spanCount: Int, private val spacing: Int, private val includeEdge: Boolean, private val headerNum: Int) : RecyclerView.ItemDecoration() {

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State?) {
        val position = parent.getChildAdapterPosition(view) - headerNum // item position

        if (position >= 0) {
            val column = position % spanCount // item column

            if (includeEdge) {
                outRect.left = spacing - column * spacing / spanCount // spacing - column * ((1f / spanCount) * spacing)
                outRect.right = (column + 1) * spacing / spanCount // (column + 1) * ((1f / spanCount) * spacing)

                if (position < spanCount) { // top edge
                    outRect.top = spacing
                }
                outRect.bottom = spacing // item bottom
            } else {
                outRect.left = column * spacing / spanCount // column * ((1f / spanCount) * spacing)
                outRect.right = spacing - (column + 1) * spacing / spanCount // spacing - (column + 1) * ((1f /    spanCount) * spacing)
                if (position >= spanCount) {
                    outRect.top = spacing // item top
                }
            }
        } else {
            outRect.left = 0
            outRect.right = 0
            outRect.top = 0
            outRect.bottom = 0
        }
    }
}