导览：由于平时RecyclerView 经常用分割线，所以每次用都要查询。要么搜api要么搜demo。大概看了下项目用到的整理几个demo。作为备查，大家可以作为字典根据需要更改。没什么技术含量，就是方便一下。

Gride RecyclerView

给gridRecycleView 实现分割线
tip:建议recycleview的长宽模式设为wrapcontent divider的作用主要提供颜色和默认边框值 均可自己设置

public class GridItemDividerDecoration extends RecyclerView.ItemDecoration {
    private int mRedundant;
    public static final int VERTICAL = 1;
    public static final int Horizon = 0;
    private Drawable mDivider;
    private int mThickness;
    private int mOratation;


    public GridItemDividerDecoration(Drawable divider, int orantation) {
        this.mDivider = divider;
        this.mOratation = orantation;
        setThickness();
    }

    public GridItemDividerDecoration(Drawable divider, int orantation, int thick) {//亲测横向纵向都可以的
        this.mDivider = divider;
        this.mOratation = orantation;
        setThickness(thick);
    }

    private void setThickness() {
        if (mOratation == VERTICAL) {
            mThickness = mDivider.getIntrinsicHeight();
        } else if (mOratation == Horizon) {
            mThickness = mDivider.getIntrinsicWidth();
        }
    }

    private void setThickness(int thickness) {//用于自己设置分割线宽度
        mThickness = thickness;
    }


    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        super.onDrawOver(c, parent, state);
        int spancount = ((GridLayoutManager) parent.getLayoutManager()).getSpanCount();
        mRedundant = parent.getChildCount() % spancount;
        mRedundant = mRedundant == 0 ? spancount : mRedundant;//最后一排的item个数
        final int underlineNum = parent.getChildCount() - mRedundant;//下划线的child的个数
        final Drawable divider = mDivider;
        final int thickness = mThickness;
        for (int i = 0; i < underlineNum; i++) {//给非最后一排的item画边边
            View child = parent.getChildAt(i);
            if (mOratation == VERTICAL) {
                divider.setBounds(child.getLeft(), child.getBottom(), child.getRight(), child.getBottom() + thickness);
            }
            if (mOratation == Horizon) {
                divider.setBounds(child.getRight(), child.getTop(), child.getRight() + thickness, child.getBottom());
            }
            divider.draw(c);
        }

    }
}

水平间距 HorizontalItemDecoration

/**
 * 定义水平方向的距离
 */
public class HorizontalItemDecoration extends RecyclerView.ItemDecoration {
    private int space;//定义2个Item之间的距离

    public HorizontalItemDecoration(int space, Context mContext) {
        this.space = dip2px(space,mContext);
    }

    @Override
    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        int position = parent.getChildAdapterPosition(view);
        int totalCount = parent.getAdapter().getItemCount();
        if (position == 0) {//第一个
            outRect.left = 0;
            outRect.right = space / 2;
        } else if (position == totalCount - 1) {//最后一个
            outRect.left = space / 2;
            outRect.right = 0;
        } else {//中间其它的
            outRect.left = space / 2;
            outRect.right = space / 2;
        }
    }

    public int dip2px(float dpValue,Context context) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
}

竖直间距

public class MyDecoration extends RecyclerView.ItemDecoration {

    private int size = 2;

    public MyDecoration(int size) {
        this.size = size;
    }

    @Override
    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        //设置间距
        outRect.bottom = size;
    }

    @Override
    public void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        super.onDraw(c, parent, state);
        Paint paint = new Paint();
        paint.setColor(BaseApplication.getInstance().getResources().getColor(R.color.c_e6e6e6));
        //获取item的数量
        int count = parent.getChildCount();
        //设置要绘制的矩形的left、right、top、bottom值
        int left = parent.getPaddingLeft()+20;
        int right = parent.getWidth() - parent.getPaddingRight()-20;
        for (int i = 0; i < count; i++){
            //获取对应的item
            View view = parent.getChildAt(i);
            float top = view.getBottom();
            float bottom = view.getBottom() + size;
            //绘制矩形
            c.drawRect(left,top,right,bottom,paint);
        }
    }
}