ios 以编程方式设置 UIButton 的中心 - SWIFT
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Set the center of a UIButton programmatically - SWIFT
提问by thedansaps
I have a UIButtoninside a UIView, my UIButtonhas constraints which I set in storyboard. Now, I want to set the center of the UIButtonat the center of the UIView. How will I do that programmatically?
我有一个UIButton内部 a UIView，我UIButton在故事板中设置了约束。现在，我想将 的中心设置UIButton在UIView. 我将如何以编程方式做到这一点？
回答by iRiziya
Try .centerproperty like
尝试.center像这样的属性
myButton.center = self.view.center
You can also specify xand yIf you need.
如果需要，您还可以指定x和y。
myButton.center.x = self.view.center.x // for horizontal
myButton.center.y = self.view.center.y // for vertical
回答by Prabhu.Somasundaram
This approach is using Using NSLayoutConstraint where self.cenBut is the IBoutlet for your button.
这种方法使用 Using NSLayoutConstraint 其中 self.cenBut 是您按钮的 IBoutlet。
func setupConstraints() {
let centerX = NSLayoutConstraint(item: self.cenBut, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
let centerY = NSLayoutConstraint(item: self.cenBut, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
let height = NSLayoutConstraint(item: self.cenBut, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 22)
self.cenBut.translatesAutoresizingMaskIntoConstraints = false
self.view.addConstraints([centerX, centerY, height])
}
In viewDidLoad()
在 viewDidLoad()
self.view.removeConstraints(self.view.constraints)
self.setupConstraints()
回答by Loxx
since you are using constraints, you won't be able to set the center so you need to use constraints to set the center as well:
由于您使用了约束，因此您将无法设置中心，因此您还需要使用约束来设置中心：
let centerYCon = NSLayoutConstraint(item: labelMessage,
attribute: .CenterY,
relatedBy: .Equal,
toItem: contentView,
attribute: .CenterY,
multiplier: 1.0,
constant: 0.0);
contentView.addConstraint(centerYCon);
let centerXCon = NSLayoutConstraint(item: labelMessage,
attribute: .CenterX,
relatedBy: .Equal,
toItem: contentView,
attribute: .CenterX,
multiplier: 1.0,
constant: 0.0);
contentView.addConstraint(centerXCon);
I'm assuming that you know what "programmatically" means with autolayout constraints. If you are truly using autolayout then you must have set the properties of your button to setTranslatesAutoresizingMaskIntoConstraints to false.
我假设您知道“以编程方式”对自动布局约束意味着什么。如果您真的在使用自动布局，那么您必须将按钮的属性设置为 setTranslatesAutoresizingMaskIntoConstraints 为 false。
回答by OutOfBounds
I should be
我应该
yourButton.setCenter(self.view.center);
But keep in mind that if you programmatically set the frame of a view, your layout constraints might not work as intended.
但请记住，如果您以编程方式设置视图的框架，您的布局约束可能无法按预期工作。
回答by Ashish Gupta
This can be done in 2 ways:
这可以通过两种方式完成：
myButton.center = view.center //view is your parentViewmyButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = truemyButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
myButton.center = view.center //view is your parentViewmyButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = truemyButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
