如何使用GridLayoutManager与RecyclerView设置列间距? 在我的布局中设置空白/填充没有效果。


当前回答

我最后用GridLayoutManager和HeaderView为我的RecyclerView做了这样的事情。

在下面的代码中,我在每个项目之间设置了4dp空间(每个项目周围都是2dp,整个RecyclerView周围是2dp填充)。

在layout.xml:

<android.support.v7.widget.RecyclerView
    android:id="@+id/recycleview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="2dp" />

在你的片段/活动中:

GridLayoutManager manager = new GridLayoutManager(getContext(), 3);
recyclerView.setLayoutManager(manager);
int spacingInPixels = Utils.dpToPx(2);
recyclerView.addItemDecoration(new SpacesItemDecoration(spacingInPixels));

创建SpaceItemDecoration.java:

public class SpacesItemDecoration extends RecyclerView.ItemDecoration {

    private int mSpacing;

    public SpacesItemDecoration(int spacing) {
        mSpacing = spacing;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView recyclerView, RecyclerView.State state) {
        outRect.left = mSpacing;
        outRect.top = mSpacing;
        outRect.right = mSpacing;
        outRect.bottom = mSpacing;
    }
}

在Utils.java:

public static int dpToPx(final float dp) {
    return Math.round(dp * (Resources.getSystem().getDisplayMetrics().xdpi / DisplayMetrics.DENSITY_DEFAULT));
}

其他回答

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));

只有一个简单的解决方案,您可以记住并在任何需要的地方实施。没有bug,没有疯狂的计算。在卡片/物品布局中放置空白,并在RecyclerView中放置相同大小的填充:

item_layout.xml

<CardView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:margin="10dp">

activity_layout.xml

<RecyclerView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp"/>

更新:

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();
    }
}
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) {
        StaggeredGridLayoutManager.LayoutParams params = (StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams();
        int column = params.getSpanIndex();

        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
            }
        }
    }
}

与edwardaa的回答略有不同,不同之处在于列是如何确定的,因为在一些情况下,例如具有不同高度的项目,列不能简单地通过% spanCount确定

对我来说,完美的解决方案是设置RecyclerView的宽度它的layoutmanager为GridLayoutManager为wrap_content