我有一个非常简单的方法在RecyclerView中添加一个分隔符。使用自定义适配器修改回收器视图布局，然后与回收器视图项目一起添加带有背景色(将是分隔色)的线性布局，并添加1dp的高度(或根据您的要求)和宽度以匹配父级。

下面是一个示例代码。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical" android:layout_width="match_parent"
              android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:padding="18dp">

        <TextView
            android:id="@+id/list_row_SNO"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight=".8"
            android:layout_gravity="end"
            android:text="44."
            android:textAlignment="center"
            android:textSize="24sp"
            android:textColor="@color/colorBlack"
            android:fontFamily="sans-serif-condensed" />

        <TextView
            android:id="@+id/list_row_Heading"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight=".2"
            android:layout_gravity="start"
            android:text="Student's application for leave and this what"
            android:textAlignment="textStart"
            android:textSize="24sp"
            android:textColor="@color/colorBlack"
            android:fontFamily="sans-serif-condensed" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@color/colorHighlight">
    </LinearLayout>

</LinearLayout>

使用RecyclerView itemdecoration -一个基本的分隔符样本在Kotlin android

一个完整的示例，包括一个构建器，添加边缘或使用资源颜色的可能性

    class SeparatorDecoration constructor(ctx: Context, @ColorRes dividerColor: Int, heightDp: Float) :
    RecyclerView.ItemDecoration() {

    private val mPaints = Paint()

    init {
        mPaints.color = dividerColor
        val thickness = TypedValue.applyDimension(
            TypedValue.COMPLEX_UNIT_DIP,
            heightDp,
            ctx.resources.displayMetrics
        )
        mPaints.strokeWidth = thickness
    }

    override fun getItemOffsets(
        outRect: Rect,
        view: View,
        parent: RecyclerView,
        state: RecyclerView.State
    ) {
        val params = view.layoutParams as RecyclerView.LayoutParams

        // and add a separator to any view but the last one
        val p = params.viewAdapterPosition

        // and add a separator to any view but the last one
        if (p < state.itemCount) outRect[0, 0, 0] =
            mPaints.strokeWidth.toInt() // left, top, right, bottom
        else outRect.setEmpty() // 0, 0, 0, 0
    }

    override fun onDraw(c: Canvas, parent: RecyclerView, state: RecyclerView.State) {

        // we set the stroke width before, so as to correctly draw the line we have to offset by width / 2
        val offset = (mPaints.strokeWidth / 2).roundToInt()

        // this will iterate over every visible view
        for (i in 0 until parent.childCount) {
            // get the view
            val view: View = parent.getChildAt(i)
            val params = view.layoutParams as RecyclerView.LayoutParams

            // get the position
            val position = params.viewAdapterPosition

            // and finally draw the separator
            if (position < state.itemCount) {
                c.drawLine(
                    view.left.toFloat(),
                    (view.bottom + offset).toFloat(),
                    view.right.toFloat(), (view.bottom + offset).toFloat(), mPaints
                )
            }
        }
    }
  }

设置很简单。只需将您的装饰与其余的初始设置一起添加到您的recyclerView。

 val decoration = SeparatorDecoration(context, R.color.primaryColor, 1.5f)
 recyclerview.addItemDecoration(decoration)

这里有一个装饰，可以让你设置项目之间的间距以及边缘的间距。这适用于水平和垂直布局。

class LinearSpacingDecoration(
    @Px private val itemSpacing: Int,
    @Px private val edgeSpacing: Int = 0
): RecyclerView.ItemDecoration() {
    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
        val count = parent.adapter?.itemCount ?: 0
        val position = parent.getChildAdapterPosition(view)
        val leading = if (position == 0) edgeSpacing else itemSpacing
        val trailing = if (position == count - 1) edgeSpacing else 0
        outRect.run {
            if ((parent.layoutManager as? LinearLayoutManager)?.orientation == LinearLayout.VERTICAL) {
                top = leading
                bottom = trailing
            } else {
                left = leading
                right = trailing
            }
        }
    }
}

用法:

recyclerView.addItemDecoration(LinearSpacingDecoration(itemSpacing = 10, edgeSpacing = 20))

这实际上并不能解决问题，但是作为一种临时的解决方法，您可以在XML布局中的卡片上设置useCompatPadding属性，使其与在前lollipop版本中测量的相同。

card_view:cardUseCompatPadding="true"

因为我已经设置了ItemAnimators。ItemDecorator不会随着动画一起进入或退出。

我只是在我的项目视图布局文件中为每个项目设置了一个视图行。它解决了我的案子。对于一个简单的分割器来说，我觉得它的魔法太多了。

<View
    android:layout_width="match_parent"
    android:layout_height="1px"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:background="@color/lt_gray"/>

只需添加

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

此外，您可能还需要添加依赖项 实现“com.android.support: recyclerview-v7:28.0.0”

为了自定义它，你可以添加一个自定义drawable:

DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL);
itemDecorator.setDrawable(ContextCompat.getDrawable(getContext(), R.drawable.divider));

你可以自由地使用任何自定义绘图，例如:

<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="rectangle">
    <solid android:color="@color/colorPrimary"/>
    <size android:height="0.5dp"/>
</shape>