下面是我在Kotlin中如何做的，在项目之间设置一个默认大小为10dp的简单空间:

class SimpleItemDecoration(context: Context, space: Int = 10) : RecyclerView.ItemDecoration() {

    private val spaceInDp = ConvertUtil.dpToPx(context, space)

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {

        outRect.left = spaceInDp
        outRect.right = spaceInDp
        outRect.bottom = spaceInDp
        // Add top margin only for the first item to avoid double space between items
        if (parent.getChildAdapterPosition(view) == 0) {
            outRect.top = spaceInDp
        }
    }
}

这是dpToPx方法:

fun dpToPx(context: Context, dp: Int): Int {
        return (dp * context.resources.displayMetrics.density).toInt()
    }

然后像这样将它添加到RecyclerView中:(感谢@MSpeed)

recyclerView.addItemDecoration(SimpleItemDecoration(context))

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)

最新的方法是这样的，例如在Fragment的onCreateView中使用:

        val recyclerView = rootView.findViewById<RecyclerView>(R.id.recycler_view)
        recyclerView.adapter = mListAdapter
        recyclerView.layoutManager = LinearLayoutManager(context)
        rootView.context.let {
            val dividerItemDecoration = MaterialDividerItemDecoration(
                it,
                MaterialDividerItemDecoration.VERTICAL
            )
            dividerItemDecoration.isLastItemDecorated = false

            // https://github.com/material-components/material-components-android/blob/master/docs/components/Divider.md
            // Needed if you did not set colorOnSurface in your theme because otherwise the default color would be pink_900 -> default according to Material should be colorOnSurface (12% opacity applied automatically on top).
//            dividerItemDecoration.setDividerColorResource(it, R.color.colorDivider)

            recyclerView.addItemDecoration(dividerItemDecoration)
        }

我想你们可以忘记之前所有的解。

对于GridLayoutManager，我使用这个:

public class GridSpacesItemDecoration : RecyclerView.ItemDecoration
{
    private int space;

    public GridSpacesItemDecoration(int space) {
        this.space = space;
    }

    public override void GetItemOffsets(Android.Graphics.Rect outRect, View view, RecyclerView parent, RecyclerView.State state)
    {
        var position = parent.GetChildLayoutPosition(view);

        /// Only for GridLayoutManager Layouts
        var manager = parent.GetLayoutManager() as GridLayoutManager;

        if (parent.GetChildLayoutPosition(view) < manager.SpanCount)
            outRect.Top = space;

        if (position % 2 != 0) {
            outRect.Right = space;
        }

        outRect.Left = space;
        outRect.Bottom = space;
    }
}

这适用于任何跨度。

请注意一下Alex Fu在GitHub上的这个文件: 链接

它是“直接从支持演示中提取”的diveritemdecoration .java示例文件。

在我的项目中导入这个文件后，我能够很好地获得分隔线，并将其作为项目装饰添加到回收器视图。

下面是我的onCreateView在我的片段中包含Recyclerview的样子:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_recycler_view, container, false);

    mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
    mRecyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL));

    mRecyclerView.setHasFixedSize(true);
    mLayoutManager = new LinearLayoutManager(getActivity());
    mRecyclerView.setLayoutManager(mLayoutManager);
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());

    return rootView;
}

我确信可以做额外的造型，但这只是一个起点。：）