具有相对宽度/高度的iOS8自动版式 [英] IOS8 Autolayout with relative width / height

问题描述

我需要使用单个UIControl自动布置情节提要UIView. UIControl应该居中，长宽比应为1:1，并且应始终使用90％的超级视图宽度或高度，具体取决于设备的方向，而不会发生剪切.

I need to autolayout a storyboard UIView with a single UIControl. The UIControl should be centered, needs to have a aspect ratio of 1:1 and should always use 90% of the superviews width or height depending on the device orientation without clipping.

我添加了4个约束

1. 中心Y对齐-视图-超级视图
2. 中心X对齐-视图-超级视图
3. 等宽-视图-乘数设置为0.9的超级视图
4. 纵横比-视图-乘数设置为1:1的视图

此设置在纵向模式下工作正常，但在横向模式下失败. (请参见下面的图片)

This setup works fine in portrait mode but fails in landscape mode. (See pictures below)

我需要哪种约束来解决此问题.如果设备旋转了，我是否需要更改约束条件?

What kind of constraint do i need to solve this problem. Do i have to change the constraints if the device is rotated?

人像模式

风景模式-错误

横向模式-样机.这是我想要的.

Landscape mode - mockup. Thats what i want.

推荐答案

这是一种实现方法:

1. 从上面列出的四个约束开始:中心X，中心Y，等宽(0.9乘数)和长宽比，它们的优先级均为1000.
2. 将等宽"的优先级更改为750.这将使自动版面配置"在必要时忽略或修改此约束.
3. 添加等高线"(视图-超级视图)约束，但将其乘以0.9使其小于或等于，而不是等于.保留其优先级为1000.

现在，当您处于纵向时，通过使红色框的宽度像以前一样为90％，自动版式"将能够满足您的所有限制.切换到横向时，等高"约束将确保红色框不会超过高度的90％，因为该约束的优先级为1000，但是自动布局"还会使框尽可能大，以尝试最适合等宽"约束.

Now, when you are in portrait, Auto Layout will be able to satisfy all of your constraints by making the width of the red box to be 90% as before. When you switch to landscape, the Equal Heights constraint will ensure that the red box doesn't grow beyond 90% of the height since this constraint has a 1000 priority, but Auto Layout will also make the box as big as possible in an attempt to best serve the Equal Widths constraint.

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