Ios 如何使用Swift以编程方式添加约束
从上周开始,我就一直在努力想办法解决这个问题,没有进一步的进展。好的,因此我需要使用以下代码以编程方式将Swift中的一些约束应用于Ios 如何使用Swift以编程方式添加约束,ios,swift,uiview,autolayout,nslayoutconstraint,Ios,Swift,Uiview,Autolayout,Nslayoutconstraint,从上周开始,我就一直在努力想办法解决这个问题,没有进一步的进展。好的,因此我需要使用以下代码以编程方式将Swift中的一些约束应用于ui视图: var new_view:UIView! = UIView(frame: CGRectMake(0, 0, 100, 100)); new_view.backgroundColor = UIColor.redColor(); view.addSubview(new_view); var constX:NSLayoutConstraint = NSLay
ui视图
:
var new_view:UIView! = UIView(frame: CGRectMake(0, 0, 100, 100));
new_view.backgroundColor = UIColor.redColor();
view.addSubview(new_view);
var constX:NSLayoutConstraint = NSLayoutConstraint(item: new_view, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0);
self.view.addConstraint(constX);
var constY:NSLayoutConstraint = NSLayoutConstraint(item: new_view, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0);
self.view.addConstraint(constY);
var constW:NSLayoutConstraint = NSLayoutConstraint(item: new_view, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: new_view, attribute: NSLayoutAttribute.Width, multiplier: 1, constant: 0);
self.view.addConstraint(constW);
var constH:NSLayoutConstraint = NSLayoutConstraint(item: new_view, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: new_view, attribute: NSLayoutAttribute.Height, multiplier: 1, constant: 0);
self.view.addConstraint(constH);
但是Xcode会返回这种奇怪的输出:
2014-10-03 09:48:12.657 Test[35088:2454916] Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)
(
"<NSLayoutConstraint:0x7fa4ea446830 UIView:0x7fa4ea429290.centerX == UIView:0x7fa4ea4470f0.centerX>",
"<NSAutoresizingMaskLayoutConstraint:0x7fa4ea4516c0 h=--& v=--& UIView:0x7fa4ea429290.midX == + 50>",
"<NSLayoutConstraint:0x7fa4ea452830 'UIView-Encapsulated-Layout-Width' H:[UIView:0x7fa4ea4470f0(375)]>",
"<NSAutoresizingMaskLayoutConstraint:0x7fa4ea446db0 h=-&- v=-&- 'UIView-Encapsulated-Layout-Left' H:|-(0)-[UIView:0x7fa4ea4470f0] (Names: '|':UIWindow:0x7fa4ea444b20 )>"
)
Will attempt to recover by breaking constraint <NSLayoutConstraint:0x7fa4ea446830 UIView:0x7fa4ea429290.centerX == UIView:0x7fa4ea4470f0.centerX>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in
<UIKit/UIView.h> may also be helpful.
2014-10-03 09:48:12.658 Test[35088:2454916] Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)
(
"<NSLayoutConstraint:0x7fa4ea44d160 UIView:0x7fa4ea429290.centerY == UIView:0x7fa4ea4470f0.centerY>",
"<NSAutoresizingMaskLayoutConstraint:0x7fa4ea451b30 h=--& v=--& UIView:0x7fa4ea429290.midY == + 50>",
"<NSLayoutConstraint:0x7fa4ea44cf00 'UIView-Encapsulated-Layout-Height' V:[UIView:0x7fa4ea4470f0(667)]>",
"<NSAutoresizingMaskLayoutConstraint:0x7fa4ea452700 h=-&- v=-&- 'UIView-Encapsulated-Layout-Top' V:|-(0)-[UIView:0x7fa4ea4470f0] (Names: '|':UIWindow:0x7fa4ea444b20 )>"
)
Will attempt to recover by breaking constraint <NSLayoutConstraint:0x7fa4ea44d160 UIView:0x7fa4ea429290.centerY == UIView:0x7fa4ea4470f0.centerY>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2014-10-03 09:48:12.657测试[35088:2454916]无法同时满足约束条件。可能下面列表中至少有一个约束是您不想要的。试着这样做:(1)看看每个约束,试着找出你不期望的约束;(2) 找到添加了不需要的约束的代码,然后修复它。(注意:如果您看到不理解的NSAutoresizingMaskLayoutConstraints,请参阅UIView属性TranslatesAutoResizingMaskToConstraints的文档)
(
"",
"",
"",
""
)
将尝试通过打破约束进行恢复
在UIViewAlertForUnsatifiableConstraints处创建一个符号断点,以便在调试器中捕获该断点。中列出的UIView上UIConstraintBasedLayoutDebugging类别中的方法
也可能有帮助。
2014-10-03 09:48:12.658测试[35088:2454916]无法同时满足约束条件。可能下面列表中至少有一个约束是您不想要的。试着这样做:(1)看看每个约束,试着找出你不期望的约束;(2) 找到添加了不需要的约束的代码,然后修复它。(注意:如果您看到不理解的NSAutoresizingMaskLayoutConstraints,请参阅UIView属性TranslatesAutoResizingMaskToConstraints的文档)
(
"",
"",
"",
""
)
将尝试通过打破约束进行恢复
在UIViewAlertForUnsatifiableConstraints处创建一个符号断点,以便在调试器中捕获该断点。中列出的UIView上UIConstraintBasedLayoutDebugging类别中的方法也可能会有所帮助。
你能帮我吗?
非常感谢您是否计划在
UIViewController的UIView
中放置一个宽度为100、高度为100的正方形UIView
?如果是这样,您可以尝试以下6种自动布局样式之一(Swift 5/iOS 12.2):
1.使用NSLayoutConstraint
初始值设定项
2.使用可视化格式语言
4.使用UIView.AutoresizingMask
注:弹簧和支柱将在运行时转换为相应的自动布局约束
override func viewDidLoad() {
let newView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
newView.backgroundColor = UIColor.red
view.addSubview(newView)
newView.translatesAutoresizingMaskIntoConstraints = true
newView.center = CGPoint(x: view.bounds.midX, y: view.bounds.midY)
newView.autoresizingMask = [UIView.AutoresizingMask.flexibleLeftMargin, UIView.AutoresizingMask.flexibleRightMargin, UIView.AutoresizingMask.flexibleTopMargin, UIView.AutoresizingMask.flexibleBottomMargin]
}
5.使用nslayoutachor
6.使用intrinsicContentSize
和nslayoutachor
结果:
您是否计划在UIViewController
的UIView
中放置一个宽度为100、高度为100的正方形UIView
?如果是这样,您可以尝试以下6种自动布局样式之一(Swift 5/iOS 12.2):
1.使用NSLayoutConstraint
初始值设定项
2.使用可视化格式语言
4.使用UIView.AutoresizingMask
注:弹簧和支柱将在运行时转换为相应的自动布局约束
override func viewDidLoad() {
let newView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
newView.backgroundColor = UIColor.red
view.addSubview(newView)
newView.translatesAutoresizingMaskIntoConstraints = true
newView.center = CGPoint(x: view.bounds.midX, y: view.bounds.midY)
newView.autoresizingMask = [UIView.AutoresizingMask.flexibleLeftMargin, UIView.AutoresizingMask.flexibleRightMargin, UIView.AutoresizingMask.flexibleTopMargin, UIView.AutoresizingMask.flexibleBottomMargin]
}
5.使用nslayoutachor
6.使用intrinsicContentSize
和nslayoutachor
结果:
正如错误消息所示,问题在于您有类型为NSAutoresizingMaskLayoutConstraints
的约束与显式约束冲突,因为new\u view.TranslatesAutoResizingMaskToConstraints
设置为true
这是在代码中创建的视图的默认设置。您可以按如下方式将其关闭:
var new_view:UIView! = UIView(frame: CGRectMake(0, 0, 100, 100))
new_view.translatesAutoresizingMaskIntoConstraints = false
此外,您的宽度和高度限制也很奇怪。如果希望视图具有恒定宽度,这是正确的方法:
new_view.addConstraint(NSLayoutConstraint(
item:new_view, attribute:NSLayoutAttribute.Width,
relatedBy:NSLayoutRelation.Equal,
toItem:nil, attribute:NSLayoutAttribute.NotAnAttribute,
multiplier:0, constant:100))
(将100替换为所需的宽度。)
如果部署目标是iOS 9.0或更高版本,则可以使用以下较短的代码:
new_view.widthAnchor.constraintEqualToConstant(100).active = true
无论如何,对于这样的布局(固定大小且在父视图中居中),使用自动调整大小遮罩并让系统将遮罩转换为约束会更简单:
var new_view:UIView! = UIView(frame: CGRectMake(0, 0, 100, 100))
new_view.backgroundColor = UIColor.redColor();
view.addSubview(new_view);
// This is the default setting but be explicit anyway...
new_view.translatesAutoresizingMaskIntoConstraints = true
new_view.autoresizingMask = [ .FlexibleTopMargin, .FlexibleBottomMargin,
.FlexibleLeftMargin, .FlexibleRightMargin ]
new_view.center = CGPointMake(view.bounds.midX, view.bounds.midY)
请注意,即使同时使用自动布局,使用自动调整大小也是完全合法的。(UIKit在内部的许多地方仍然使用自动调整大小。)问题是,很难对使用自动调整大小的视图应用其他约束。正如错误消息所示,问题是您的约束类型为nsAutoResizengMaskLayoutConstraints
,与显式约束冲突,因为new\u view.translatesAutoresizingMaskIntoConstraints
设置为true
var xCenterConstraint : NSLayoutConstraint!
var yCenterConstraint: NSLayoutConstraint!
xCenterConstraint = NSLayoutConstraint(item: self.view, attribute: .CenterX, relatedBy: .Equal, toItem: (Your view NAme), attribute: .CenterX, multiplier: 1, constant: 0)
self.view.addConstraint(xCenterConstraint)
yCenterConstraint = NSLayoutConstraint(item: self.view, attribute: .CenterY, relatedBy: .Equal, toItem: (Your view Name), attribute: .CenterY, multiplier: 1, constant: 0)
self.view.addConstraint(yCenterConstraint)
这是在代码中创建的视图的默认设置。您可以按如下方式将其关闭:
var new_view:UIView! = UIView(frame: CGRectMake(0, 0, 100, 100))
new_view.translatesAutoresizingMaskIntoConstraints = false
此外,您的宽度和高度限制也很奇怪。如果希望视图具有恒定宽度,这是正确的方法:
new_view.addConstraint(NSLayoutConstraint(
item:new_view, attribute:NSLayoutAttribute.Width,
relatedBy:NSLayoutRelation.Equal,
toItem:nil, attribute:NSLayoutAttribute.NotAnAttribute,
multiplier:0, constant:100))
(将100替换为所需的宽度。)
如果部署目标是iOS 9.0或更高版本,则可以使用以下较短的代码:
new_view.widthAnchor.constraintEqualToConstant(100).active = true
无论如何,对于这样的布局(固定大小且在父视图中居中),使用自动调整大小遮罩并让系统将遮罩转换为约束会更简单:
var new_view:UIView! = UIView(frame: CGRectMake(0, 0, 100, 100))
new_view.backgroundColor = UIColor.redColor();
view.addSubview(new_view);
// This is the default setting but be explicit anyway...
new_view.translatesAutoresizingMaskIntoConstraints = true
new_view.autoresizingMask = [ .FlexibleTopMargin, .FlexibleBottomMargin,
.FlexibleLeftMargin, .FlexibleRightMargin ]
new_view.center = CGPointMake(view.bounds.midX, view.bounds.midY)
请注意,即使同时使用自动布局,使用自动调整大小也是完全合法的。(UIKit在内部的许多地方仍然使用自动调整大小。)问题是,很难对使用自动调整大小的视图应用附加约束。这有助于我直观地学习,因此这是一个补充答案
var xCenterConstraint : NSLayoutConstraint!
var yCenterConstraint: NSLayoutConstraint!
xCenterConstraint = NSLayoutConstraint(item: self.view, attribute: .CenterX, relatedBy: .Equal, toItem: (Your view NAme), attribute: .CenterX, multiplier: 1, constant: 0)
self.view.addConstraint(xCenterConstraint)
yCenterConstraint = NSLayoutConstraint(item: self.view, attribute: .CenterY, relatedBy: .Equal, toItem: (Your view Name), attribute: .CenterY, multiplier: 1, constant: 0)
self.view.addConstraint(yCenterConstraint)
样板代码
以下每个示例都是独立于其他示例的
销左边缘
myView.leading=leadingMargin+20
方法1:锚定样式
let margins = view.layoutMarginsGuide
myView.leadingAnchor.constraint(equalTo: margins.leadingAnchor, constant: 20).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.leading, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.leadingMargin, multiplier: 1.0, constant: 20.0).isActive = true
myView.widthAnchor.constraint(equalToConstant: 200).isActive = true
myView.heightAnchor.constraint(equalToConstant: 100).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 200).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.height, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 100).isActive = true
myView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
myView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerY, multiplier: 1, constant: 0).isActive = true
- 除了
引导锚
,还有牵引锚
、顶锚
和底锚
方法2:NSLayoutConstraint样式
let margins = view.layoutMarginsGuide
myView.leadingAnchor.constraint(equalTo: margins.leadingAnchor, constant: 20).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.leading, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.leadingMargin, multiplier: 1.0, constant: 20.0).isActive = true
myView.widthAnchor.constraint(equalToConstant: 200).isActive = true
myView.heightAnchor.constraint(equalToConstant: 100).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 200).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.height, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 100).isActive = true
myView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
myView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerY, multiplier: 1, constant: 0).isActive = true
- 除了
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerY, multiplier: 1, constant: 0).isActive = true
var constW = NSLayoutConstraint(item: newView,
attribute: .Width,
relatedBy: .Equal,
toItem: nil,
attribute: .NotAnAttribute,
multiplier: 1,
constant: 100)
newView.addConstraint(constW)
var constH = NSLayoutConstraint(item: newView,
attribute: .Height,
relatedBy: .Equal,
toItem: nil,
attribute: .NotAnAttribute,
multiplier: 1,
constant: 100)
newView.addConstraint(constH)
// creating the view
let newView = UIView()
newView.backgroundColor = UIColor.redColor()
newView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(newView)
// creating the constraint
// attribute and relation cannot be set directyl you need to create a cariable of them
let layout11 = NSLayoutAttribute.CenterX
let layout21 = NSLayoutRelation.Equal
let layout31 = NSLayoutAttribute.CenterY
let layout41 = NSLayoutAttribute.Width
let layout51 = NSLayoutAttribute.Height
let layout61 = NSLayoutAttribute.NotAnAttribute
// defining all the constraint
let horizontalConstraint = NSLayoutConstraint(item: newView, attribute: layout11, relatedBy: layout21, toItem: view, attribute: layout11, multiplier: 1, constant: 0)
let verticalConstraint = NSLayoutConstraint(item: newView, attribute: layout31, relatedBy: layout21, toItem: view, attribute: layout31, multiplier: 1, constant: 0)
let widthConstraint = NSLayoutConstraint(item: newView, attribute: layout41, relatedBy: layout21, toItem: nil, attribute: layout61, multiplier: 1, constant: 100)
let heightConstraint = NSLayoutConstraint(item: newView, attribute: layout51, relatedBy: layout21, toItem: nil, attribute: layout61, multiplier: 1, constant: 100)
// adding all the constraint
NSLayoutConstraint.activateConstraints([horizontalConstraint,verticalConstraint,widthConstraint,heightConstraint])
view.translatesAutoresizingMaskIntoConstraints = false
let attributes: [NSLayoutAttribute] = [.top, .bottom, .right, .left]
NSLayoutConstraint.activate(attributes.map {
NSLayoutConstraint(item: view, attribute: $0, relatedBy: .equal, toItem: view.superview, attribute: $0, multiplier: 1, constant: 0)
})
view.translatesAutoresizingMaskIntoConstraints = false
view.topAnchor.constraint(equalTo: view.superview!.topAnchor).isActive = true
view.bottomAnchor.constraint(equalTo: view.superview!.bottomAnchor).isActive = true
view.leadingAnchor.constraint(equalTo: view.superview!.leadingAnchor, constant: 10).isActive = true
view.trailingAnchor.constraint(equalTo: view.superview!.trailingAnchor, constant: 10).isActive = true
override func viewDidLoad() {
super.viewDidLoad()
let myLabel = UILabel()
myLabel.labelFrameUpdate(label: myLabel, text: "Welcome User", font: UIFont(name: "times new roman", size: 40)!, textColor: UIColor.red, textAlignment: .center, numberOfLines: 0, borderWidth: 2.0, BorderColor: UIColor.red.cgColor)
self.view.addSubview(myLabel)
let myLabelhorizontalConstraint = NSLayoutConstraint(item: myLabel, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: self.view, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0)
let myLabelverticalConstraint = NSLayoutConstraint(item: myLabel, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: self.view, attribute: NSLayoutAttribute.centerY, multiplier: 1, constant: 0)
let mylabelLeading = NSLayoutConstraint(item: myLabel, attribute: NSLayoutAttribute.leading, relatedBy: NSLayoutRelation.equal, toItem: self.view, attribute: NSLayoutAttribute.leading, multiplier: 1, constant: 10)
let mylabelTrailing = NSLayoutConstraint(item: myLabel, attribute: NSLayoutAttribute.trailing, relatedBy: NSLayoutRelation.equal, toItem: self.view, attribute: NSLayoutAttribute.trailing, multiplier: 1, constant: -10)
let myLabelheightConstraint = NSLayoutConstraint(item: myLabel, attribute: NSLayoutAttribute.height, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 50)
NSLayoutConstraint.activate(\[myLabelhorizontalConstraint, myLabelverticalConstraint, myLabelheightConstraint,mylabelLeading,mylabelTrailing\])
}
extension UILabel
{
func labelFrameUpdate(label:UILabel,text:String = "This is sample Label",font:UIFont = UIFont(name: "times new roman", size: 20)!,textColor:UIColor = UIColor.red,textAlignment:NSTextAlignment = .center,numberOfLines:Int = 0,borderWidth:CGFloat = 2.0,BorderColor:CGColor = UIColor.red.cgColor){
label.translatesAutoresizingMaskIntoConstraints = false
label.text = text
label.font = font
label.textColor = textColor
label.textAlignment = textAlignment
label.numberOfLines = numberOfLines
label.layer.borderWidth = borderWidth
label.layer.borderColor = UIColor.red.cgColor
}
}
import UIKit
class ViewController: UIViewController {
let redView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.backgroundColor = .red
return view
}()
override func viewDidLoad() {
super.viewDidLoad()
setupViews()
setupAutoLayout()
}
func setupViews() {
view.backgroundColor = .white
view.addSubview(redView)
}
func setupAutoLayout() {
// Available from iOS 9 commonly known as Anchoring System for AutoLayout...
redView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 20).isActive = true
redView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -20).isActive = true
redView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
redView.heightAnchor.constraint(equalToConstant: 300).isActive = true
// You can also modified above last two lines as follows by commenting above & uncommenting below lines...
// redView.topAnchor.constraint(equalTo: view.topAnchor, constant: 20).isActive = true
// redView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
}
}
/*
// regular use
1.leftAnchor
2.rightAnchor
3.topAnchor
// intermediate use
4.widthAnchor
5.heightAnchor
6.bottomAnchor
7.centerXAnchor
8.centerYAnchor
// rare use
9.leadingAnchor
10.trailingAnchor
etc. (note: very project to project)
*/
view.snp.makeConstraints { make in
make.edges.equalToSuperview()
}
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let myImageView:UIImageView = UIImageView()
myImageView.backgroundColor = UIColor.red
myImageView.image = UIImage(named:"sample_dog")!
myImageView.translatesAutoresizingMaskIntoConstraints = false
myImageView.layer.borderColor = UIColor.red.cgColor
myImageView.layer.borderWidth = 10
self.view.addSubview(myImageView)
view.removeConstraints(view.constraints)
view.addConstraint(NSLayoutConstraint(
item: myImageView,
attribute: .top,
relatedBy: .equal,
toItem: view,
attribute: .top,
multiplier: 1,
constant:100)
)
view.addConstraint(NSLayoutConstraint(
item: myImageView,
attribute: .centerX,
relatedBy: .equal,
toItem: view,
attribute: .centerX,
multiplier: 1,
constant:0)
)
view.addConstraint(NSLayoutConstraint(
item: myImageView,
attribute: .height,
relatedBy: .equal,
toItem: view,
attribute: .width,
multiplier: 0.5,
constant:40))
view.addConstraint(NSLayoutConstraint(
item: myImageView,
attribute: .width,
relatedBy: .equal,
toItem: view,
attribute: .width,
multiplier: 0.5,
constant:40))
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
var yellowView: UIView!
var redView: UIView!
override func loadView() {
// UI
let view = UIView()
view.backgroundColor = .white
yellowView = UIView()
yellowView.backgroundColor = .yellow
view.addSubview(yellowView)
redView = UIView()
redView.backgroundColor = .red
view.addSubview(redView)
// Layout
redView.translatesAutoresizingMaskIntoConstraints = false
yellowView.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
yellowView.topAnchor.constraint(equalTo: view.topAnchor, constant: 20),
yellowView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
yellowView.widthAnchor.constraint(equalToConstant: 80),
yellowView.heightAnchor.constraint(equalToConstant: 80),
redView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -20),
redView.trailingAnchor.constraint(equalTo: view.trailingAnchor,constant: -20),
redView.widthAnchor.constraint(equalToConstant: 80),
redView.heightAnchor.constraint(equalToConstant: 80)
])
self.view = view
}
fileprivate func setupName() {
lblName.text = "Hello world"
// Step 1
lblName.translatesAutoresizingMaskIntoConstraints = false
//Step 2
self.view.addSubview(lblName)
//Step 3
NSLayoutConstraint.activate([
lblName.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
lblName.centerYAnchor.constraint(equalTo: self.view.centerYAnchor)
])
}
view.addSubview(myView1)
myView1.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
myView1.centerXAnchor.constraint(equalTo: view.centerXAnchor),
myView1.centerYAnchor.constraint(equalTo: view.centerYAnchor),
myView1.widthAnchor.constraint(equalToConstant: 100),
myView1.heightAnchor.constraint(equalToConstant: 100),
])
view.addSubview(myView2)
myView2.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
myView2.leadingAnchor.constraint(equalTo: view.leadingAnchor,constant: 16),
myView2.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor,constant: 16),
myView2.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.3),
myView2.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.3)
])
- firstView.coverWholeSuperview()
- firstView.constraints(size: CGSize(width: 44, height: 44), centerX: view.centerXAnchor, centerY: view.centerXAnchor)
- firstView.constraints(top: view.topAnchor,
leading: secondView.leadingAnchor,
bottom: view.bottomAnchor,
trailing: secondView.trailingAnchor,
padding: UIEdgeInsets(top: 12, left: 12, bottom: 12, right: 12))
extension UIView {
/// Attaches all sides of the receiver to its parent view
func coverWholeSuperview(margin: CGFloat = 0.0) {
let view = superview
layoutAttachTop(to: view, margin: margin)
layoutAttachBottom(to: view, margin: margin)
layoutAttachLeading(to: view, margin: margin)
layoutAttachTrailing(to: view, margin: margin)
}
/// Attaches the top of the current view to the given view's top if it's a superview of the current view
/// or to it's bottom if it's not (assuming this is then a sibling view).
@discardableResult
func layoutAttachTop(to: UIView? = nil, margin: CGFloat = 0.0) -> NSLayoutConstraint {
let view: UIView? = to ?? superview
let isSuperview = view == superview
let constraint = NSLayoutConstraint(item: self, attribute: .top, relatedBy: .equal,
toItem: view, attribute: isSuperview ? .top : .bottom, multiplier: 1.0,
constant: margin)
superview?.addConstraint(constraint)
return constraint
}
/// Attaches the bottom of the current view to the given view
@discardableResult
func layoutAttachBottom(to: UIView? = nil, margin: CGFloat = 0.0, priority: UILayoutPriority? = nil) -> NSLayoutConstraint {
let view: UIView? = to ?? superview
let isSuperview = (view == superview) || false
let constraint = NSLayoutConstraint(item: self, attribute: .bottom, relatedBy: .equal,
toItem: view, attribute: isSuperview ? .bottom : .top, multiplier: 1.0,
constant: -margin)
if let priority = priority {
constraint.priority = priority
}
superview?.addConstraint(constraint)
return constraint
}
/// Attaches the leading edge of the current view to the given view
@discardableResult
func layoutAttachLeading(to: UIView? = nil, margin: CGFloat = 0.0) -> NSLayoutConstraint {
let view: UIView? = to ?? superview
let isSuperview = (view == superview) || false
let constraint = NSLayoutConstraint(item: self, attribute: .leading, relatedBy: .equal,
toItem: view, attribute: isSuperview ? .leading : .trailing, multiplier: 1.0,
constant: margin)
superview?.addConstraint(constraint)
return constraint
}
/// Attaches the trailing edge of the current view to the given view
@discardableResult
func layoutAttachTrailing(to: UIView? = nil, margin: CGFloat = 0.0, priority: UILayoutPriority? = nil) -> NSLayoutConstraint {
let view: UIView? = to ?? superview
let isSuperview = (view == superview) || false
let constraint = NSLayoutConstraint(item: self, attribute: .trailing, relatedBy: .equal,
toItem: view, attribute: isSuperview ? .trailing : .leading, multiplier: 1.0,
constant: -margin)
if let priority = priority {
constraint.priority = priority
}
superview?.addConstraint(constraint)
return constraint
}
// For anchoring View
struct AnchoredConstraints {
var top, leading, bottom, trailing, width, height, centerX, centerY: NSLayoutConstraint?
}
@discardableResult
func constraints(top: NSLayoutYAxisAnchor? = nil, leading: NSLayoutXAxisAnchor? = nil, bottom: NSLayoutYAxisAnchor? = nil,
trailing: NSLayoutXAxisAnchor? = nil, padding: UIEdgeInsets = .zero, size: CGSize = .zero,
centerX: NSLayoutXAxisAnchor? = nil, centerY: NSLayoutYAxisAnchor? = nil,
centerXOffset: CGFloat = 0, centerYOffset: CGFloat = 0) -> AnchoredConstraints {
translatesAutoresizingMaskIntoConstraints = false
var anchoredConstraints = AnchoredConstraints()
if let top = top {
anchoredConstraints.top = topAnchor.constraint(equalTo: top, constant: padding.top)
}
if let leading = leading {
anchoredConstraints.leading = leadingAnchor.constraint(equalTo: leading, constant: padding.left)
}
if let bottom = bottom {
anchoredConstraints.bottom = bottomAnchor.constraint(equalTo: bottom, constant: -padding.bottom)
}
if let trailing = trailing {
anchoredConstraints.trailing = trailingAnchor.constraint(equalTo: trailing, constant: -padding.right)
}
if size.width != 0 {
anchoredConstraints.width = widthAnchor.constraint(equalToConstant: size.width)
}
if size.height != 0 {
anchoredConstraints.height = heightAnchor.constraint(equalToConstant: size.height)
}
if let centerX = centerX {
anchoredConstraints.centerX = centerXAnchor.constraint(equalTo: centerX, constant: centerXOffset)
}
if let centerY = centerY {
anchoredConstraints.centerY = centerYAnchor.constraint(equalTo: centerY, constant: centerYOffset)
}
[anchoredConstraints.top, anchoredConstraints.leading, anchoredConstraints.bottom,
anchoredConstraints.trailing, anchoredConstraints.width,
anchoredConstraints.height, anchoredConstraints.centerX,
anchoredConstraints.centerY].forEach { $0?.isActive = true }
return anchoredConstraints
}
}
boxView.items = [
new_view.boxed.centerX().centerY().relativeWidth(1.0).relativeHeight(1.0)
]
imagePreview!.isUserInteractionEnabled = true
imagePreview!.isExclusiveTouch = true
imagePreview!.contentMode = UIView.ContentMode.scaleAspectFit
// Remove all constraints
imagePreview!.removeAllConstraints()
// Add the new constraints
let guide = view.safeAreaLayoutGuide
imagePreview!.translatesAutoresizingMaskIntoConstraints = false
imagePreview!.leadingAnchor.constraint(equalTo: guide.leadingAnchor).isActive = true
imagePreview!.trailingAnchor.constraint(equalTo: guide.trailingAnchor).isActive = true
imagePreview!.heightAnchor.constraint(equalTo: guide.heightAnchor, multiplier: 1.0).isActive = true
extension UIView {
func removeAllConstraints() {
var _superview = self.superview
func removeAllConstraintsFromView(view: UIView) { for c in view.constraints { view.removeConstraint(c) } }
while let superview = _superview {
for constraint in superview.constraints {
if let first = constraint.firstItem as? UIView, first == self {
superview.removeConstraint(constraint)
}
if let second = constraint.secondItem as? UIView, second == self {
superview.removeConstraint(constraint)
}
}
_superview = superview.superview
}
self.removeConstraints(self.constraints)
self.translatesAutoresizingMaskIntoConstraints = true
}
}
class ViewController: UIViewController {
let rectView: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
override func viewDidLoad() {
super.viewDidLoad()
setupViews()
}
private func setupViews() {
rectView.backgroundColor = .red
view.addSubview(rectView)
rectView.snp.makeConstraints {
$0.center.equalToSuperview()
}
}
}