The most common layout object is PatternLayout, which formats messages according to a supplied pattern.
最常见的layout对象是PatternLayout，它根据所提供的模式对消息进行格式化。
There are no limits to how a layout object can affect the views in a collection view.
布局对象作用在集合视图上没有什么限制。
A layout object never touches the views it manages directly because it does not actually own any of those views.
布局对象并不直接作用于视图，因为它并不实际拥有这些视图。
Unlike cells, supplementary views are not mandatory, and their usage and placement is controlled by the layout object being used.
和单元格视图不同的是，增补视图不是强制要求的，他们的使用和位置受控于布局对象。
You typically use the flow layout object to implement grids-that is, rows and columns of items-but the flow layout supports any type of linear flow.
通常情况下，你可以使用流动布局对象来实现网格(由行列元素组成)，但是流动布局对象支持任何类型的流线型布局。
Thus, you provide the data, the layout object provides the placement information, and the collection view merges the two pieces together to achieve the final appearance.
于是呢，你提供的数据信息，布局对象提供的位置信息，由集合视图综合起来实现最终的展示效果。
Thus, you provide the data, the layout object provides the placement information, and the collection view merges the two pieces together to achieve the final appearance.
于是呢，你提供的数据信息，布局对象提供的位置信息，由集合视图综合起来实现最终的展示效果。
应用推荐