View Content Mode

最新推荐文章于 2020-03-04 18:29:00 发布

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最新推荐文章于 2020-03-04 18:29:00 发布

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本文链接：https://blog.youkuaiyun.com/andy812110/article/details/45664867

本文介绍了视图内容模式(ContentModes)的基本概念及其作用原理。内容模式控制视图如何响应几何变化并决定是否重复使用内容。文章详细解释了不同模式如ScaleToFill、AspectFit和Redraw之间的区别。

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Content Modes

Each view has a content mode that controls how the view recycles its content in response to changes in theview’s geometry and whether it recycles its content at all. When a view is first displayed, it renders its contentas usual and the results are captured in an underlying bitmap. After that, changes to the view’s geometry donot always cause the bitmap to be recreated. Instead, the value in the contentMode property determineswhether the bitmap should be scaled to fit the new bounds or simply pinned to one corner or edge of theview.

详情可以查看View Programming Guide里的Content Mode

各个选项都很简单 Scale To Fill 和 Aspect Fit的区别就是方向上的适应整个View

Redraw：to redraw themselvesduring scaling and resizing operations

Setting your view’s content mode to this value forces the system tocall your view’s drawRect: method in response to geometry changes. In general, you should avoid using thisvalue whenever possible, and you should certainly not use it with the standard system views.

view Mode 有下面这几个选项: