安卓。 StaggeredGridLayoutManager 确定跨度索引答案

【问题标题】：Android. StaggeredGridLayoutManager determine span index安卓。 StaggeredGridLayoutManager 确定跨度索引
【发布时间】：2021-07-15 02:38:25
【问题描述】：

我使用recycleView 和StaggeredGridLayoutManager（列数为3）。我需要确定当前单元格位于哪一列（按位置）。是否有可能做到这一点？请帮我。注意：我的单元格的高度不同（正方形或矩形）

【问题讨论】：

标签： android android-recyclerview staggeredgridlayoutmanager

【解决方案1】：

要从位置获取列：您可以使用位置的余数/模数乘以 3。
要从位置获取行：您可以将其除以 3。

0  | 1  | 2
3  | 4  | 5
6  | 7  | 8
9  | 10 | 11
12 | 13 | 14
15 | 16 | 17
18 | 19 | 20

例子

for (int position = 0; position <= 20; position++) {
    Log.d("LOG_TAG", "Item: " + position + " In Row: " + position / 3 + " In Col: " + position % 3);
}

日志：

2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 0 In Row: 0 In Col: 0
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 1 In Row: 0 In Col: 1
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 2 In Row: 0 In Col: 2
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 3 In Row: 1 In Col: 0
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 4 In Row: 1 In Col: 1
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 5 In Row: 1 In Col: 2
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 6 In Row: 2 In Col: 0
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 7 In Row: 2 In Col: 1
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 8 In Row: 2 In Col: 2
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 9 In Row: 3 In Col: 0
2021-04-21 00:33:41.634 14288-14288/.. D/LOG_TAG: Item: 10 In Row: 3 In Col: 1
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 11 In Row: 3 In Col: 2
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 12 In Row: 4 In Col: 0
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 13 In Row: 4 In Col: 1
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 14 In Row: 4 In Col: 2
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 15 In Row: 5 In Col: 0
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 16 In Row: 5 In Col: 1
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 17 In Row: 5 In Col: 2
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 18 In Row: 6 In Col: 0
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 19 In Row: 6 In Col: 1
2021-04-21 00:33:41.635 14288-14288/.. D/LOG_TAG: Item: 20 In Row: 6 In Col: 2

【讨论】：

感谢您的回答，但我的单元格可以有不同的高度（正方形或矩形）
@anna 我想说，如果不分享您如何设计这些正方形和矩形的高度，很难做到这一点

【解决方案2】：

我认为您可以使用子视图的LayoutParams 来确定跨度索引。带有ItemDecoration 的示例可能看起来像这样（Kotlin）：

class MyItemDecoration : RecyclerView.ItemDecoration() {
    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
        super.getItemOffsets(outRect, view, parent, state)
        val params = view.layoutParams as StaggeredGridLayoutManager.LayoutParams
        when(params.spanIndex) {
            0 -> outRect.apply {
                left = 20
                right = 10
            }
            1 -> outRect.apply {
                left = 10
                right = 10
            }
            2 -> outRect.apply {
                left = 10
                right = 20
            }
        }
    }
}

【讨论】：