AndroidRecyclerviewGridLayoutManager列间距 - Android Recyclerview GridLayoutManager column spacing

解决方案：
RecyclerViews支持ItemDecoration的概念:特殊补偿和绘画在每个元素。见这个答案,您可以使用然后通过添加

原文：

RecyclerViews support the concept of ItemDecoration: special offsets and drawing around each element. As seen in this answer, you can use

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;
    }
  }
}

Then add it via

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

网友:使用“outRect。顶级=空间outRect和删除。底,如果你不想惹“如果第一的位置”。;-)

(原文：Use 'outRect.top = space' and remove 'outRect.bottom' if you don't want to mess with the 'if for the first position'. ;-])

网友:@zatziky——是的,如果你已经在使用顶部和底部填充作为你的一部分(使用),然后你可以稍微重组的事情。然而,如果你不你只是移动如果检查最后一次(就像你仍然希望底部填充最后一项)。

(原文：@zatziky - yep, if you already use top and bottom padding as part of your RecyclerView (and useclipToPadding="false"), then you can restructure things slightly. If you don't however, you'd just be moving the if check to be the last time (as you'd still want the bottom padding on the last item).)

网友:我试着这个,除非我添加了android:clipToPadding=“false”和android:填充=“@dimen/间距”RecyclerView外面的间距不符合项之间的间距。我已经试了所有下面的答案,认为@yqritc是最干净,最简单的解决方案。

(原文：I tried this and unless I added android:clipToPadding="false" and android:padding="@dimen/spacing" to the RecyclerView the outside spacing did not match the spacing between items. I have tried all the answers below and think the solution by @yqritc was the cleanest and simplest.)

网友:@ianhanniballake,而这是在使用单孔布局管理器,这对多跨布局管理器失败。

(原文：@ianhanniballake, while this works when using a single span layout manager, it fails for multi-span layout manager.)

网友:值得提及,你必须修改outRect的所有字段。否则你可以抵消之前的观点。

(原文：It worth to mention, that you have to modify all fields of outRect. otherwise you can get the offset of the previous view.)

解决方案：
代码运行良好,每一列有相同的宽度:使用它:1)没有边缘2)与边缘

原文：

Following code works well, and each column has same width:

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
            }
        }
    }
}

To use it:

1) no edge

int spanCount = 3;
int spacing = 50;
boolean includeEdge = false;
recyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));

2) with edge

int spanCount = 3;
int spacing = 50;
boolean includeEdge = true;
recyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));

网友:谢谢,它太棒了!

(原文：thanks, It works great!)

网友:工作除非你有项目,有各种各样的跨越,像标题。

(原文：Works unless you have items that have various spans, like headers.)

网友:工作就像一个魅力!

(原文：Worked like a charm!)

网友:似乎只有在垂直模式工作

(原文：Seems to only work for vertical mode)

解决方案：
下面是一步一步简单的解决方案,如果你想要的物品和周围的相等的间距等于项目大小。ItemOffsetDecoration实现在你的源代码,添加ItemOffsetDecorationrecyclerview。项抵消值应该是您想要添加一半大小的实际价值之间的空间项目。同时,设置项目抵消值作为其recyclerview填充,并指定android:clipToPadding=false。完成了。

原文：

The following is the step-by-step simple solution if you want the equal spacing around items and equal item sizes.

ItemOffsetDecoration

public class ItemOffsetDecoration extends RecyclerView.ItemDecoration {

    private int mItemOffset;

    public ItemOffsetDecoration(int itemOffset) {
        mItemOffset = itemOffset;
    }

    public ItemOffsetDecoration(@NonNull Context context, @DimenRes int itemOffsetId) {
        this(context.getResources().getDimensionPixelSize(itemOffsetId));
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
            RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        outRect.set(mItemOffset, mItemOffset, mItemOffset, mItemOffset);
    }
}

Implementation

In your source code, add ItemOffsetDecoration to your recyclerview.
Item offset value should be half size of the actual value you want to add as space between items.

mRecyclerView.setLayoutManager(new GridLayoutManager(context, NUM_COLUMNS);
ItemOffsetDecoration itemDecoration = new ItemOffsetDecoration(context, R.dimen.item_offset);
mRecyclerView.addItemDecoration(itemDecoration);

Also, set item offset value as padding for its recyclerview, and specify android:clipToPadding=false.

<android.support.v7.widget.RecyclerView
    android:id="@+id/recyclerview_grid"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:clipToPadding="false"
    android:padding="@dimen/item_offset"/>

DONE.

网友:简单而优雅

(原文：Simple and elegant)

网友:最佳答案——伟大的工作!

(原文：Best answer here - great job!)

网友:最佳答案-m8:感谢)

(原文：best answer- thanks m8 :))

网友:完美!就像一个魅力。

(原文：perfect! Works like a charm.)

网友:好先生!!

(原文：Well done sir!!)

解决方案：
试试这个。它会照顾相等的间距。作品都使用列表、网格,进行。编辑更新的代码应该处理的大部分角落案件与跨越,取向,等等。请注意,如果使用setSpanSizeLookupGridLayoutManager(),设置setSpanIndexCacheEnabled()建议由于性能的原因。与进行注意,似乎,似乎有一个错误的索引孩子变得古怪,很难跟踪,所以下面的代码与StaggeredGridLayoutManager可能不会工作得很好。希望它可以帮助。

原文：

Try this. It'll take care of equal spacing all around. Works both with List, Grid, and StaggeredGrid.

Edited

The updated code should handle most of the corner cases with spans, orientation, etc. Note that if using setSpanSizeLookup() with GridLayoutManager, setting setSpanIndexCacheEnabled() is recommended for performance reasons.

Note, it seems that with StaggeredGrid, there's seems to be a bug where the index of the children gets wacky and hard to track so the code below might not work very well with StaggeredGridLayoutManager.

public class ListSpacingDecoration extends RecyclerView.ItemDecoration {

  private static final int VERTICAL = OrientationHelper.VERTICAL;

  private int orientation = -1;
  private int spanCount = -1;
  private int spacing;
  private int halfSpacing;


  public ListSpacingDecoration(Context context, @DimenRes int spacingDimen) {

    spacing = context.getResources().getDimensionPixelSize(spacingDimen);
    halfSpacing = spacing / 2;
  }

  public ListSpacingDecoration(int spacingPx) {

    spacing = spacingPx;
    halfSpacing = spacing / 2;
  }

  @Override
  public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {

    super.getItemOffsets(outRect, view, parent, state);

    if (orientation == -1) {
        orientation = getOrientation(parent);
    }

    if (spanCount == -1) {
        spanCount = getTotalSpan(parent);
    }

    int childCount = parent.getLayoutManager().getItemCount();
    int childIndex = parent.getChildAdapterPosition(view);

    int itemSpanSize = getItemSpanSize(parent, childIndex);
    int spanIndex = getItemSpanIndex(parent, childIndex);

    /* INVALID SPAN */
    if (spanCount < 1) return;

    setSpacings(outRect, parent, childCount, childIndex, itemSpanSize, spanIndex);
  }

  protected void setSpacings(Rect outRect, RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {

    outRect.top = halfSpacing;
    outRect.bottom = halfSpacing;
    outRect.left = halfSpacing;
    outRect.right = halfSpacing;

    if (isTopEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
        outRect.top = spacing;
    }

    if (isLeftEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
        outRect.left = spacing;
    }

    if (isRightEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
        outRect.right = spacing;
    }

    if (isBottomEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
        outRect.bottom = spacing;
    }
  }

  @SuppressWarnings("all")
  protected int getTotalSpan(RecyclerView parent) {

    RecyclerView.LayoutManager mgr = parent.getLayoutManager();
    if (mgr instanceof GridLayoutManager) {
        return ((GridLayoutManager) mgr).getSpanCount();
    } else if (mgr instanceof StaggeredGridLayoutManager) {
        return ((StaggeredGridLayoutManager) mgr).getSpanCount();
    } else if (mgr instanceof LinearLayoutManager) {
        return 1;
    }

    return -1;
  }

  @SuppressWarnings("all")
  protected int getItemSpanSize(RecyclerView parent, int childIndex) {

    RecyclerView.LayoutManager mgr = parent.getLayoutManager();
    if (mgr instanceof GridLayoutManager) {
        return ((GridLayoutManager) mgr).getSpanSizeLookup().getSpanSize(childIndex);
    } else if (mgr instanceof StaggeredGridLayoutManager) {
        return 1;
    } else if (mgr instanceof LinearLayoutManager) {
        return 1;
    }

    return -1;
  }

  @SuppressWarnings("all")
  protected int getItemSpanIndex(RecyclerView parent, int childIndex) {

    RecyclerView.LayoutManager mgr = parent.getLayoutManager();
    if (mgr instanceof GridLayoutManager) {
        return ((GridLayoutManager) mgr).getSpanSizeLookup().getSpanIndex(childIndex, spanCount);
    } else if (mgr instanceof StaggeredGridLayoutManager) {
        return childIndex % spanCount;
    } else if (mgr instanceof LinearLayoutManager) {
        return 0;
    }

    return -1;
  }

  @SuppressWarnings("all")
  protected int getOrientation(RecyclerView parent) {

    RecyclerView.LayoutManager mgr = parent.getLayoutManager();
    if (mgr instanceof LinearLayoutManager) {
        return ((LinearLayoutManager) mgr).getOrientation();
    } else if (mgr instanceof GridLayoutManager) {
        return ((GridLayoutManager) mgr).getOrientation();
    } else if (mgr instanceof StaggeredGridLayoutManager) {
        return ((StaggeredGridLayoutManager) mgr).getOrientation();
    }

    return VERTICAL;
  }

  protected boolean isLeftEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {

    if (orientation == VERTICAL) {

        return spanIndex == 0;

    } else {

        return (childIndex == 0) || isFirstItemEdgeValid((childIndex < spanCount), parent, childIndex);
    }
  }

  protected boolean isRightEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {

    if (orientation == VERTICAL) {

        return (spanIndex + itemSpanSize) == spanCount;

    } else {

        return isLastItemEdgeValid((childIndex >= childCount - spanCount), parent, childCount, childIndex, spanIndex);
    }
  }

  protected boolean isTopEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {

    if (orientation == VERTICAL) {

        return (childIndex == 0) || isFirstItemEdgeValid((childIndex < spanCount), parent, childIndex);

    } else {

        return spanIndex == 0;
    }
  }

  protected boolean isBottomEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {

    if (orientation == VERTICAL) {

        return isLastItemEdgeValid((childIndex >= childCount - spanCount), parent, childCount, childIndex, spanIndex);

    } else {

        return (spanIndex + itemSpanSize) == spanCount;
    }
  }

  protected boolean isFirstItemEdgeValid(boolean isOneOfFirstItems, RecyclerView parent, int childIndex) {

    int totalSpanArea = 0;
    if (isOneOfFirstItems) {
        for (int i = childIndex; i >= 0; i--) {
            totalSpanArea = totalSpanArea + getItemSpanSize(parent, i);
        }
    }

    return isOneOfFirstItems && totalSpanArea <= spanCount;
  }

  protected boolean isLastItemEdgeValid(boolean isOneOfLastItems, RecyclerView parent, int childCount, int childIndex, int spanIndex) {

    int totalSpanRemaining = 0;
    if (isOneOfLastItems) {
        for (int i = childIndex; i < childCount; i++) {
            totalSpanRemaining = totalSpanRemaining + getItemSpanSize(parent, i);
        }
    }

    return isOneOfLastItems && (totalSpanRemaining <= spanCount - spanIndex);
  }
}

Hope it helps.

网友:非常感谢对这个答案

(原文：thnx for this answer)

网友:这应该是验证答案。谢谢你！

(原文：This should be the verified answer. Thank you.)

网友:我有双跨后的第一道物品。这是因为parent.getChildCount第一项()返回1,2第二等等。所以,我建议添加空间项目的前边缘:outRect。顶级=childIndex

(原文：I've got double span just after first line of items. It happens because parent.getChildCount() returns 1 for first item, 2 for second and so on. So, I suggest add space to items of the top edge like: outRect.top = childIndex < spanCount ? spacingInPixels : 0; And add bottom space for each item: outRect.bottom = spacingInPixels;)

网友:在滚动的时候RecyclerView,间距变了。

(原文：At the time of scrolling RecyclerView, spacing changed.)

网友:我认为parent.getChildCount()应该改为“parent.getLayoutManager().getItemCount()”。同时,isBottomEdge功能需要改变“回归childIndex>=childCount-spanCount+spanIndex”。改变这些之后,我得到了相等的间距。但是请注意,这个解决方案不给我等于项目大小如果跨数大于2因为偏移值取决于位置是不同的。

(原文：I think parent.getChildCount() should be changed to "parent.getLayoutManager().getItemCount()". Also, isBottomEdge function need to be changed to "return childIndex >= childCount - spanCount + spanIndex". After changing these, I got equal spacing. But please note that this solution does not give me equal item sizes if span count is greater than 2 since offset value is different depending on position.)

解决方案：
下面的代码将处理StaggeredGridLayoutManager、GridLayoutManagerLinearLayoutManager。然后使用它

原文：

The following code will handle StaggeredGridLayoutManager, GridLayoutManager, and LinearLayoutManager.

public class SpacesItemDecoration extends RecyclerView.ItemDecoration {

    private int halfSpace;

    public SpacesItemDecoration(int space) {
        this.halfSpace = space / 2;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {

        if (parent.getPaddingLeft() != halfSpace) {
            parent.setPadding(halfSpace, halfSpace, halfSpace, halfSpace);
            parent.setClipToPadding(false);
        }

        outRect.top = halfSpace;
        outRect.bottom = halfSpace;
        outRect.left = halfSpace;
        outRect.right = halfSpace;
    }
}

Then use it

mRecyclerView.addItemDecoration(new SpacesItemDecoration(mMargin));

网友:这是最简单的一个。一个重要的事情是你也要添加填充到父在xml。在我的例子中,它的工作方式。谢谢。

(原文：This is the most simple one. One important thing is you also got to add the padding to the parent in the xml. In my case, it work that way. Thanks.)

网友:实际上增加了填充到父(回收商的观点)。

(原文：The SpaceItemDecoration actually adds the padding to the parent (the recycler view).)

网友:只填充出现(右侧)当我没有设置填充到父在xml中

(原文：only halfSpace padding appeared(to the right side) when I had not set the padding to the parent in xml)

网友:只是缺失的右边?也许你有半空间设置为leftPadding左边已经在xml,这段代码只剩下检查填充设置RecyclerView与否。

(原文：It was only missing on the right side? It may be that you have half space set as the leftPadding on the left side already in the xml and this code only checks if the left padding is set on the RecyclerView or not.)

网友:这是最简洁的解决方案!

(原文：this is the most concise solution!)

解决方案：
回答上面有澄清方法设置边缘处理GridLayoutManager和LinearLayoutManager。但是StaggeredGridLayoutManagerPirdadSakhizada的回答说,“与StaggeredGridLayoutManager可能不会工作得很好。“这应该对indexOfSpan问题。你可以通过这种方式:

原文：

Answers above have clarified ways to set margin handling GridLayoutManager and LinearLayoutManager.

But for StaggeredGridLayoutManager, Pirdad Sakhizada's answer say it "might not work very well with StaggeredGridLayoutManager." It should be the problem about indexOfSpan.

You can get it by this way:

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();
    }
}