隐藏自动版式的UIView：如何让现有的NSLayoutConstraint更新这一项 [英] Hide autolayout UIView : How to get existing NSLayoutConstraint to update this one

问题描述

我知道如何修改现有的约束。但我想知道是否有人已经找到了解决方案，得到了约束，而无需保存这一个作为一个属性。

目前的解决方案来设置约束高度：

1）保存在NSLayoutConstraint一个变量：

  NSLayoutConstraint * heightConstraint = [NSLayoutConstraint constraintWithItem：MyView的
                                                                    属性：NSLayoutAttributeHeight
                                                                    relatedBy：NSLayoutRelationEqual
                                                                       toItem：无
                                                                    属性：NSLayoutAttributeNotAnAttribute
                                                                   事半功倍：1.0F
                                                                     常数：20];
[self.view addConstraint：heightConstraint];
 

2）设置保存到0.0（隐藏这种观点的约束的常数）

  [heightConstraint setConstant：200];
 

---

我在寻找这样一个解决方案：

  [MyView的setConstraint：@0。 forAttribute：NSLayoutAttributeHeight]
 

解决方案

我刚刚建立了这个类别（<一个href=\"https://github.com/damienromito/UIView-UpdateAutoLayoutConstraints\">https://github.com/damienromito/UIView-UpdateAutoLayoutConstraints)当您希望该更新限制：

  //你可以使用工具来隐藏/显示一个UIView
[myView1 hideByHeight：YES];
 

或只是做，以隐藏与自动布局的UIView的：

  //隐藏查看
[myView1 setConstraintConstant：0 forAttribute：NSLayoutAttributeHeight];
 

I know how to modify a existing constraint. But I would to know if someone has found a solution to get a constraint without save this one as a property.

Current solution to set Constraint height:

1) save NSLayoutConstraint in a variable:

NSLayoutConstraint *heightConstraint = [NSLayoutConstraint constraintWithItem:myView
                                                                    attribute:NSLayoutAttributeHeight
                                                                    relatedBy:NSLayoutRelationEqual
                                                                       toItem:nil
                                                                    attribute:NSLayoutAttributeNotAnAttribute
                                                                   multiplier:1.0f
                                                                     constant:20];
[self.view addConstraint:heightConstraint];

2) Set the constant of the Constraint saved to "0.0" ( to hide this view)

[heightConstraint setConstant:200];

---

I'm looking for a solution like this:

 [myView setConstraint:@"0." forAttribute:NSLayoutAttributeHeight]

解决方案

I just built this Category (https://github.com/damienromito/UIView-UpdateAutoLayoutConstraints) that update constrains when you want:

//you can use tools to hide/show a uiview
[myView1 hideByHeight:YES];

Or just do it to hide an UIView with autolayout:

//Hide View 
[myView1 setConstraintConstant:0 forAttribute:NSLayoutAttributeHeight];

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