Ios 使用界面生成器进行灵活布局

我想实现这种布局，将调整横向模式的宽度，并将保持所有空间（间隙）的定义。因此，

UITextView

的单列在一行中有两列，当扣除左-右间隙和中间间隙时，这两列应占左边宽度的一半

+---------------------------------------------+
|                     <y>                     |
|    +-----------------------------------+    |
|    |                                   |    |
|    +-----------------------------------+    |
|    +-----------------------------------+    |
|    |                                   |    |
|    +-----------------------------------+    |
|    +----------------+ +----------------+    |
|<x> |        50%     | |      50%       | <x>|
|    +----------------+ +----------------+    |
|    +-----------------------------------+    |
|    |                                   |    |
|    +-----------------------------------+    |
|                                             |
+---------------------------------------------+

---

围绕要居中的对象添加其他视图

+-----------------------------------------------+
|                     <y>                       |
|    +-------------------------------------+    |
|    |+-----------------------------------+|    |
|    ||                                   ||    |
|    |+-----------------------------------+|    |
|    |+-----------------------------------+|    |
|    ||                                   ||    |
|    |+-----------------------------------+|    |
|    |+----------------+ +----------------+|    |
|<x> ||        50%     | |      50%       || <x>|
|    |+----------------+ +----------------+|    |
|    |+-----------------------------------+|    |
|    ||                                   ||    |
|    |+-----------------------------------+|    |
|    +-------------------------------------+    |
|                                               |
+-----------------------------------------------+

---

这如何帮助我让所有文本字段使用所有可用宽度（减去左右间距）？我应该在interface builder中执行什么约束设置？

+-----------------------------------------------+
|                     <y>                       |
|    +-------------------------------------+    |
|    |+-----------------------------------+|    |
|    ||                                   ||    |
|    |+-----------------------------------+|    |
|    |+-----------------------------------+|    |
|    ||                                   ||    |
|    |+-----------------------------------+|    |
|    |+----------------+ +----------------+|    |
|<x> ||        50%     | |      50%       || <x>|
|    |+----------------+ +----------------+|    |
|    |+-----------------------------------+|    |
|    ||                                   ||    |
|    |+-----------------------------------+|    |
|    +-------------------------------------+    |
|                                               |
+-----------------------------------------------+

View
    Scroll View
        Content View
            View
                Round Style Text Field
                Round Style Text Field
                View
                    Round Style Text Field
                    Round Style Text Field
                Round Style Text Field