方式一 ：
添加系统默认分割线
mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
效果：
image.png
更改为自想要的颜色，修改styles的AppTheme，添加内容
<item name="android:listDivider">@color/colorAccent</item>
其中的内容可以是自定义的drawable也可使颜色。
效果：
image.png
如果需要修改高度可以通过drawable中进行设置
要实现GridView 表格效果的话
mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.HORIZONTAL));
mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
效果：
image.png
如需要代码中设置颜色或者drawable
DividerItemDecoration divider = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL);
divider.setDrawable(ContextCompat.getDrawable(this,R.drawable.custom_divider));
mRecyclerView.addItemDecoration(divider);
方式二
自定义ItemDecoration
代码（仿照百度各种结果修改的）
public class ItemDivider extends RecyclerView.ItemDecoration {
private int dividerWith = 1;
private Paint paint;
private RecyclerView.LayoutManager layoutManager;
private Drawable dividerDrawable;
// 构造方法,可以在这里做一些初始化,比如指定画笔颜色什么的
public ItemDivider() {
initPaint();
paint.setColor(0xffff0000);
}
private void initPaint() {
if (paint == null) {
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.FILL);
}
}
public ItemDivider setDividerWith(int dividerWith) {
this.dividerWith = dividerWith;
return this;
}
public ItemDivider setDividerColor(int color) {
initPaint();
paint.setColor(color);
return this;
}
public ItemDivider setDivider(Drawable divider) {
dividerDrawable = divider;
return this;
}
/**
* 指定item之间的间距(就是指定分割线的宽度) 回调顺序 1
*
* @param outRect Rect to receive the output.
* @param view The child view to decorate
* @param parent RecyclerView this ItemDecoration is decorating
* @param state The current state of RecyclerView.
*/
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (layoutManager == null) {
layoutManager = parent.getLayoutManager();
}
// 适用 LinearLayoutManager 和 GridLayoutManager
if (layoutManager instanceof LinearLayoutManager) {
int orientation = ((LinearLayoutManager) layoutManager).getOrientation();
if (orientation == LinearLayoutManager.VERTICAL) {
// 水平分割线将绘制在item底部
outRect.bottom = dividerWith;
} else if (orientation == LinearLayoutManager.HORIZONTAL) {
// 垂直分割线将绘制在item右侧
outRect.right = dividerWith;
}
if (layoutManager instanceof GridLayoutManager) {
GridLayoutManager.LayoutParams lp = (GridLayoutManager.LayoutParams) view.getLayoutParams();
// 如果是 GridLayoutManager 则需要绘制另一个方向上的分割线
if (orientation == LinearLayoutManager.VERTICAL && lp != null && lp.getSpanIndex() > 0) {
// 如果列表是垂直方向,则最左边的一列略过
outRect.left = dividerWith;
} else if (orientation == LinearLayoutManager.HORIZONTAL && lp != null && lp.getSpanIndex() > 0) {
// 如果列表是水平方向,则最上边的一列略过
outRect.top = dividerWith;
}
}
}
}
/**
* 在item 绘制之前调用(就是绘制在 item 的底层) 回调顺序 2
* 一般分割线在这里绘制
* 看到canvas,对自定义控件有一定了解的话,就能想到为什么说给RecyclerView设置分割线更灵活了
*
* @param c Canvas to draw into
* @param parent RecyclerView this ItemDecoration is drawing into
* @param state The current state of RecyclerView
*/
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDraw(c, parent, state);
// 这个值是为了补偿横竖方向上分割线交叉处间隙
int offSet = (int) Math.ceil(dividerWith * 1f / 2);
for (int i = 0; i < parent.getChildCount(); i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int left1 = child.getRight() + params.rightMargin;
int right1 = left1 + dividerWith;
int top1 = child.getTop() - offSet - params.topMargin;
int bottom1 = child.getBottom() + offSet + params.bottomMargin;
//绘制分割线(矩形)
if (dividerDrawable != null) {
dividerDrawable.setBounds(left1, top1, right1, bottom1);
dividerDrawable.draw(c);
} else {
c.drawRect(left1, top1, right1, bottom1, paint);
}
int left2 = child.getLeft() - offSet - params.leftMargin;
int right2 = child.getRight() + offSet + params.rightMargin;
int top2 = child.getBottom() + params.bottomMargin;
int bottom2 = top2 + dividerWith;
//绘制分割线(矩形)
if (dividerDrawable != null) {
dividerDrawable.setBounds(left2, top2, right2, bottom2);
dividerDrawable.draw(c);
} else {
c.drawRect(left2, top2, right2, bottom2, paint);
}
}
}
/**
* 在item 绘制之后调用(就是绘制在 item 的上层) 回调顺序 3
* 也可以在这里绘制分割线,和上面的方法 二选一
*
* @param c Canvas to draw into
* @param parent RecyclerView this ItemDecoration is drawing into
* @param state The current state of RecyclerView
*/
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDrawOver(c, parent, state);
}
}
使用方法
mRecyclerView.addItemDecoration(new ItemDivider().setDivider(ContextCompat.getDrawable(this, R.drawable.custom_divider)));
or
mRecyclerView.addItemDecoration(new ItemDivider().setDividerColor(Color.BLUE));
效果
image.png
