我们可以使用附加到recyclerview的各种装饰器来装饰物品，例如:

简单地使用下面的…从答案中提取

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};

    private Drawable mDivider;

    /**
     * Default divider will be used
     */
    public DividerItemDecoration(Context context) {
        final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
        mDivider = styledAttributes.getDrawable(0);
        styledAttributes.recycle();
    }

    /**
     * Custom divider will be used
     */
    public DividerItemDecoration(Context context, int resId) {
        mDivider = ContextCompat.getDrawable(context, resId);
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();

        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);

            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + mDivider.getIntrinsicHeight();

            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }
}

然后用上面的方法如下:

RecyclerView.ItemDecoration itemDecoration = new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST);
recyclerView.addItemDecoration(itemDecoration);

这将在列表中的每个项目之间显示分隔符，如下所示:

对于那些想要了解更多细节的人，可以看看这个指南Using the recyclerview_ CodePath Android Cliffnotes。

这里的一些答案建议使用边距，但问题是:

如果你同时添加了上边距和下边距，它们将在项目之间显示为添加的，而且它们将太大。如果只添加其中之一，则整个列表的顶部或底部都没有边距。如果你在上面加上一半的距离，在下面加上一半的距离，外层的边缘就太小了。

因此，唯一美观上正确的解决方案是系统知道在哪里正确应用的分隔符:项目之间，但不是项目的上面或下面。

这是我在Kotlin中为列显示(网格)所做的

  class ItemDecorationColumns(private val space: Int) : ItemDecoration() {

    override fun getItemOffsets(
        outRect: Rect,
        view: View,
        parent: RecyclerView,
        state: RecyclerView.State
    ) {
        val position = parent.getChildLayoutPosition(view)
        val manager = parent.layoutManager as GridLayoutManager?
        val spanCount = manager?.spanCount ?: 0

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

        if (position % 2 != 0) {
            outRect.right = space
        }
        outRect.left = space
        outRect.bottom = space
    }
}

使用

rvAlbums.addItemDecoration(ItemDecorationColumns(resources.getDimensionPixelSize(R.dimen.space)))

一个非常简单的解决方案是使用RecyclerView-FlexibleDivider

添加依赖关系:

compile 'com.yqritc:recyclerview-flexibledivider:1.4.0'

添加到你的recyclerview:

recyclerView.addItemDecoration(new HorizontalDividerItemDecoration.Builder(context).build());

这样就完成了!

使用这个类在你的RecyclerView中设置分隔符。

public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {

    private int spanCount;
    private int spacing;
    private boolean includeEdge;

    public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {
        this.spanCount = spanCount;
        this.spacing = spacing;
        this.includeEdge = includeEdge;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int position = parent.getChildAdapterPosition(view); // Item position
        int column = position % spanCount; // Item column

        if (includeEdge) {
            outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
            outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)

            if (position < spanCount) { // Top edge
                outRect.top = spacing;
            }
            outRect.bottom = spacing; // Item bottom
        } else {
            outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
            outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f / spanCount) * spacing)
            if (position >= spanCount) {
                outRect.top = spacing; // Item top
            }
        }
    }
}

这个链接对我来说很有吸引力:

https://gist.github.com/lapastillaroja/858caf1a82791b6c1a36

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private Drawable mDivider;
    private boolean mShowFirstDivider = false;
    private boolean mShowLastDivider = false;


    public DividerItemDecoration(Context context, AttributeSet attrs) {
        final TypedArray a = context
                .obtainStyledAttributes(attrs, new int[]{android.R.attr.listDivider});
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
            boolean showLastDivider) {
        this(context, attrs);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
    }

    public DividerItemDecoration(Drawable divider) {
        mDivider = divider;
    }

    public DividerItemDecoration(Drawable divider, boolean showFirstDivider,
            boolean showLastDivider) {
        this(divider);
        mShowFirstDivider = showFirstDivider;
        mShowLastDivider = showLastDivider;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
            RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        if (mDivider == null) {
            return;
        }
        if (parent.getChildPosition(view) < 1) {
            return;
        }

        if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
            outRect.top = mDivider.getIntrinsicHeight();
        } else {
            outRect.left = mDivider.getIntrinsicWidth();
        }
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        if (mDivider == null) {
            super.onDrawOver(c, parent, state);
            return;
        }

        // Initialization needed to avoid compiler warning
        int left = 0, right = 0, top = 0, bottom = 0, size;
        int orientation = getOrientation(parent);
        int childCount = parent.getChildCount();

        if (orientation == LinearLayoutManager.VERTICAL) {
            size = mDivider.getIntrinsicHeight();
            left = parent.getPaddingLeft();
            right = parent.getWidth() - parent.getPaddingRight();
        } else { //horizontal
            size = mDivider.getIntrinsicWidth();
            top = parent.getPaddingTop();
            bottom = parent.getHeight() - parent.getPaddingBottom();
        }

        for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
            View child = parent.getChildAt(i);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

            if (orientation == LinearLayoutManager.VERTICAL) {
                top = child.getTop() - params.topMargin;
                bottom = top + size;
            } else { //horizontal
                left = child.getLeft() - params.leftMargin;
                right = left + size;
            }
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }

        // show last divider
        if (mShowLastDivider && childCount > 0) {
            View child = parent.getChildAt(childCount - 1);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            if (orientation == LinearLayoutManager.VERTICAL) {
                top = child.getBottom() + params.bottomMargin;
                bottom = top + size;
            } else { // horizontal
                left = child.getRight() + params.rightMargin;
                right = left + size;
            }
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    private int getOrientation(RecyclerView parent) {
        if (parent.getLayoutManager() instanceof LinearLayoutManager) {
            LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
            return layoutManager.getOrientation();
        } else {
            throw new IllegalStateException(
                    "DividerItemDecoration can only be used with a LinearLayoutManager.");
        }
    }
}

然后在你的活动中:

mCategoryRecyclerView.addItemDecoration(
    new DividerItemDecoration(this, null));

或者如果你使用片段:

mCategoryRecyclerView.addItemDecoration(
    new DividerItemDecoration(getActivity(), null));

public class VerticalItemDecoration extends RecyclerView.ItemDecoration {

    private boolean verticalOrientation = true;
    private int space = 10;

    public VerticalItemDecoration(int value, boolean verticalOrientation) {
        this.space = value;
        this.verticalOrientation = verticalOrientation;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
                               RecyclerView.State state) {
        // Skip first item in the list
        if (parent.getChildAdapterPosition(view) != 0) {
            if (verticalOrientation) {
                outRect.set(space, 0, 0, 0);
            } else if (!verticalOrientation) {
                outRect.set(0, space, 0, 0);
            }
        }
    }
}

mCompletedShippingRecyclerView.addItemDecoration(new VerticalItemDecoration(20,false));