你需要添加下一行…

mRecyclerView.addItemDecoration(new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL));

在2016年10月的更新中，支持库v25.0.0现在有了基本水平和垂直分隔符的默认实现!

https://developer.android.com/reference/android/support/v7/widget/DividerItemDecoration.html

 recyclerView.addItemDecoration(new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL));

如果你想同时使用水平和垂直分隔符:

Define horizontal & vertical divider drawables: horizontal_divider.xml <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" > <size android:height="1dip" /> <solid android:color="#22000000" /> </shape> vertical_divider.xml <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" > <size android:width="1dip" /> <solid android:color="#22000000" /> </shape> Add this code segment below: DividerItemDecoration verticalDecoration = new DividerItemDecoration(recyclerview.getContext(), DividerItemDecoration.HORIZONTAL); Drawable verticalDivider = ContextCompat.getDrawable(getActivity(), R.drawable.vertical_divider); verticalDecoration.setDrawable(verticalDivider); recyclerview.addItemDecoration(verticalDecoration); DividerItemDecoration horizontalDecoration = new DividerItemDecoration(recyclerview.getContext(), DividerItemDecoration.VERTICAL); Drawable horizontalDivider = ContextCompat.getDrawable(getActivity(), R.drawable.horizontal_divider); horizontalDecoration.setDrawable(horizontalDivider); recyclerview.addItemDecoration(horizontalDecoration);

在res/drawable文件夹中创建一个单独的xml文件

 <?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <size android:height="1dp" />
    <solid android:color="@android:color/black" />
</shape>

在主活动中连接那个xml文件(your_file)，像这样:

DividerItemDecoration divider = new DividerItemDecoration(
    recyclerView.getContext(),
    DividerItemDecoration.VERTICAL
);
divider.setDrawable(ContextCompat.getDrawable(getBaseContext(), R.drawable.your_file));
recyclerView.addItemDecoration(divider);

所有这些答案都让我接近了答案，但它们都遗漏了一个关键细节。经过一番研究，我发现最简单的方法是将以下3个步骤结合起来:

使用支持库的DividerItemDecoration 用正确的颜色创建分隔线 在主题中设置这个分隔符为listDivider

步骤1:在配置RecyclerView时

recyclerView.addItemDecoration(
        new DividerItemDecoration(context, layoutManager.getOrientation()));

第二步:在res/drawable/divider_gray.xml这样的文件中

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <size android:width="1px" android:height="1px" />
    <solid android:color="@color/gray" />
</shape>

步骤3:在应用程序的主题

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Other theme items above -->
    <item name="android:listDivider">@drawable/divider_gray</item>
</style>

编辑:更新跳过最后的分隔符: 在使用了一些之后，我意识到它在最后一项之后画了一个分隔符，这很烦人。所以我修改了第1步，如下所示，以覆盖在DividerItemDecoration的默认行为(当然，制作一个单独的类是另一种选择):

recyclerView.addItemDecoration(
        new DividerItemDecoration(context, layoutManager.getOrientation()) {
            @Override
            public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
                int position = parent.getChildAdapterPosition(view);
                // hide the divider for the last child
                if (position == parent.getAdapter().getItemCount() - 1) {
                    outRect.setEmpty();
                } else {
                    super.getItemOffsets(outRect, view, parent, state);
                }
            }
        }
);

好了，如果不需要改变你的分割线颜色，只需对分割线装饰应用alpha。

GridLayoutManager透明的示例:

DividerItemDecoration horizontalDividerItemDecoration = new DividerItemDecoration(WishListActivity.this,
                DividerItemDecoration.HORIZONTAL);
        horizontalDividerItemDecoration.getDrawable().setAlpha(50);
        DividerItemDecoration verticalDividerItemDecoration = new DividerItemDecoration(WishListActivity.this,
                DividerItemDecoration.VERTICAL);
        verticalDividerItemDecoration.getDrawable().setAlpha(50);
        my_recycler.addItemDecoration(horizontalDividerItemDecoration);
        my_recycler.addItemDecoration(verticalDividerItemDecoration);

你仍然可以通过设置颜色来改变分割线的颜色 过滤到它。

GridLayoutManager设置tint的例子:

DividerItemDecoration horizontalDividerItemDecoration = new DividerItemDecoration(WishListActivity.this,
                DividerItemDecoration.HORIZONTAL);
        horizontalDividerItemDecoration.getDrawable().setTint(getResources().getColor(R.color.colorAccent));
        DividerItemDecoration verticalDividerItemDecoration = new DividerItemDecoration(WishListActivity.this,
                DividerItemDecoration.VERTICAL);
        verticalDividerItemDecoration.getDrawable().setAlpha(50);
        my_recycler.addItemDecoration(horizontalDividerItemDecoration);
        my_recycler.addItemDecoration(verticalDividerItemDecoration);

此外，您还可以尝试设置颜色滤镜，

 horizontalDividerItemDecoration.getDrawable().setColorFilter(colorFilter);