Android 使用 gridlayoutmanager 在 recyclerview 中的最后一个元素下方添加间距

问题描述

我正在尝试使用 GridLayoutManager 在 RecyclerView 中的最后一个元素行下方添加间距.为此，我使用自定义 ItemDecoration 并在其最后一个元素时使用底部填充，如下所示:

I am trying to add spacing below the last element row in RecyclerView with GridLayoutManager. I used custom ItemDecoration for this purpose with bottom padding when its last element as follows:

public class SpaceItemDecoration extends RecyclerView.ItemDecoration {
private int space;
private int bottomSpace = 0;

public SpaceItemDecoration(int space, int bottomSpace) {
    this.space = space;
    this.bottomSpace = bottomSpace;
}

public SpaceItemDecoration(int space) {
    this.space = space;
    this.bottomSpace = 0;
}

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

    int childCount = parent.getChildCount();
    final int itemPosition = parent.getChildAdapterPosition(view);
    final int itemCount = state.getItemCount();

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

    if (itemCount > 0 && itemPosition == itemCount - 1) {
        outRect.bottom = bottomSpace;
    }
}
}

但是这种方法的问题在于它弄乱了最后一行网格中的元素高度.我猜 GridLayoutManager 会根据左间距更改元素的高度.实现这一目标的正确方法是什么?

But the problem with this method is that it messed up the element heights in the grid in last row. I am guessing that GridLayoutManager changes the heights for elements based on spacing left. What is the correct way to achieve this?

这将适用于 LinearLayoutManager.以防万一 GridLayoutManager 有问题.

This will work correctly for a LinearLayoutManager. Just in case of a GridLayoutManager its problematic.

如果您在底部有 FAB 并且需要最后一行中的项目滚动到 FAB 上方以便它们可见，它非常有用.

Its very useful in case you have a FAB in bottom and need items in last row to scroll above FAB so that they can be visible.

推荐答案

解决这个问题的方法在于重写 GridLayoutManager 的 SpanSizeLookup.

The solution to this problem lies in overrinding the SpanSizeLookup of GridLayoutManager.

您必须在要对 RecylerView 进行膨胀的 Activity 或 Fragment 中更改 GridlayoutManager.

You have to make changes to the GridlayoutManager in the Activity or Fragment where you are inflating the RecylerView.

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //your code
    recyclerView.addItemDecoration(new PhotoGridMarginDecoration(context));

    // SPAN_COUNT is the number of columns in the Grid View
    GridLayoutManager gridLayoutManager = new GridLayoutManager(context, SPAN_COUNT);

    // With the help of this method you can set span for every type of view
    gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
        @Override
        public int getSpanSize(int position) {
            if (list.get(position).getType() == TYPE_HEADER) {
                // Will consume the whole width
                return gridLayoutManager.getSpanCount();
            } else if (list.get(position).getType() == TYPE_CONTENT) {
                // will consume only one part of the SPAN_COUNT
                return 1;
            } else if(list.get(position).getType() == TYPE_FOOTER) {
                // Will consume the whole width
                // Will take care of spaces to be left,
                // if the number of views in a row is not equal to 4
                return gridLayoutManager.getSpanCount();
            }
            return gridLayoutManager.getSpanCount();
        }
    });
    recyclerView.setLayoutManager(gridLayoutManager);
}

这篇关于Android 使用 gridlayoutmanager 在 recyclerview 中的最后一个元素下方添加间距的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！