如何以编程方式更改从故事板添加的约束？ [英] How to change constraints programmatically that is added from storyboard?

问题描述

我有一个屏幕。它将显示如下

I have one screen. It will display like below

现在点击用户我有一个帐户和密码（按钮），它将显示如下

Now When User clicked I have an Account and Password(button) it will display like below

我想相应地移动两个视图
我使用storyboard添加约束。现在需要更改编程中的约束..

I want to move both views accordingly I added constraints using storyboard.Now need to change constraints from programming..

推荐答案

您需要创建约束的IBOutlet。

You need to create an IBOutlet of your constraint.

然后在代码中设置约束的常量值：

Then you set the constant value of your constraint in code:

labelWidthConstraint.constant = newValue

如果你想要它的动画，你可以这样做：

If you want it animated you can do something like this:

labelWidthConstraint.constant = newValue
UIView.animate(withDuration: 0.3, animations: { 
    view.layoutIfNeeded()
}

目标-C

Objective-C

self.labelWidthConstraint.constant = newValue;
[UIView animateWithDuration:0.3 animations:^{        
    [self.view layoutIfNeeded];
}];

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