RecyclerViews支持ItemDecoration的概念:围绕每个元素的特殊偏移和绘图。从这个答案中可以看出，你可以使用

public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
  private int space;

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

  @Override
  public void getItemOffsets(Rect outRect, View view, 
      RecyclerView parent, RecyclerView.State state) {
    outRect.left = space;
    outRect.right = space;
    outRect.bottom = space;

    // Add top margin only for the first item to avoid double space between items
    if (parent.getChildLayoutPosition(view) == 0) {
        outRect.top = space;
    } else {
        outRect.top = 0;
    }
  }
}

然后通过

mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
int spacingInPixels = getResources().getDimensionPixelSize(R.dimen.spacing);
mRecyclerView.addItemDecoration(new SpacesItemDecoration(spacingInPixels));

我根据edwardaa的回答做了一个Kotlin版本

class RecyclerItemDecoration(private val spanCount: Int, private val spacing: Int) : RecyclerView.ItemDecoration() {

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

    val spacing = Math.round(spacing * parent.context.resources.displayMetrics.density)
    val position = parent.getChildAdapterPosition(view)
    val column = position % spanCount

    outRect.left = spacing - column * spacing / spanCount
    outRect.right = (column + 1) * spacing / spanCount

    outRect.top = if (position < spanCount) spacing else 0
    outRect.bottom = spacing
  }

}

RecyclerViews支持ItemDecoration的概念:围绕每个元素的特殊偏移和绘图。从这个答案中可以看出，你可以使用

public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
  private int space;

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

  @Override
  public void getItemOffsets(Rect outRect, View view, 
      RecyclerView parent, RecyclerView.State state) {
    outRect.left = space;
    outRect.right = space;
    outRect.bottom = space;

    // Add top margin only for the first item to avoid double space between items
    if (parent.getChildLayoutPosition(view) == 0) {
        outRect.top = space;
    } else {
        outRect.top = 0;
    }
  }
}

然后通过

mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
int spacingInPixels = getResources().getDimensionPixelSize(R.dimen.spacing);
mRecyclerView.addItemDecoration(new SpacesItemDecoration(spacingInPixels));

如果你有一个在列表和网格之间切换的拨动开关，不要忘记在设置任何新的项目装饰之前调用recyclerView.removeItemDecoration(..)。如果不是这样，那么新的间隔计算将是不正确的。

就像这样:

recyclerView.removeItemDecoration(gridItemDecorator)
recyclerView.removeItemDecoration(listItemDecorator)

if (showAsList) {
    recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
    recyclerView.addItemDecoration(listItemDecorator)
} else {
    recyclerView.layoutManager = GridLayoutManager(this, spanCount)
    recyclerView.addItemDecoration(gridItemDecorator)
}

选择的答案几乎是完美的，但根据空间的不同，项目的宽度可能不相等。(对我来说，这很关键)。所以我最终用这个代码增加了一点空间，所以项目都是相同的宽度。

   class GridSpacingItemDecoration(private val columnCount: Int, @Px preferredSpace: Int, private val includeEdge: Boolean): RecyclerView.ItemDecoration() {

    /**
     * In this algorithm space should divide by 3 without remnant or width of items can have a difference
     * and we want them to be exactly the same
     */
    private val space = if (preferredSpace % 3 == 0) preferredSpace else (preferredSpace + (3 - preferredSpace % 3))

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State?) {
        val position = parent.getChildAdapterPosition(view)

        if (includeEdge) {

            when {
                position % columnCount == 0 -> {
                    outRect.left = space
                    outRect.right = space / 3
                }
                position % columnCount == columnCount - 1 -> {
                    outRect.right = space
                    outRect.left = space / 3
                }
                else -> {
                    outRect.left = space * 2 / 3
                    outRect.right = space * 2 / 3
                }
            }

            if (position < columnCount) {
                outRect.top = space
            }

            outRect.bottom = space

        } else {

            when {
                position % columnCount == 0 -> outRect.right = space * 2 / 3
                position % columnCount == columnCount - 1 -> outRect.left = space * 2 / 3
                else -> {
                    outRect.left = space / 3
                    outRect.right = space / 3
                }
            }

            if (position >= columnCount) {
                outRect.top = space
            }
        }
    }

}

上面的回答已经阐明了设置边缘处理GridLayoutManager和LinearLayoutManager的方法。

但是对于StaggeredGridLayoutManager, Pirdad Sakhizada的回答是:“它可能不太适合StaggeredGridLayoutManager”。应该是关于IndexOfSpan的问题。

您可以通过以下方式获取:

private static class MyItemDecoration extends RecyclerView.ItemDecoration {
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        int index = ((StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams()).getSpanIndex();
    }
}