How to change position of loaded NibView in iOS Swift 4? - ios

I loaded nib view with custom frame but just show that nib view in top of superView.
I call this code in viewDidLoad.
let mb = Bundle.main.loadNibNamed("MBViewNib", owner: self, options: nil)?.first as! MBView
mb.frame = CGRect(x: 50, y: 200, width: 100, height: 100)
view.addSubview(mb)


We can use something like this:
mb = Bundle.main.loadNibNamed("MBViewNib", owner: self, options: nil)?.first as? MBView
view.addSubview(mb!)
mb.translatesAutoresizingMaskIntoConstraints = false
view.addConstraint(NSLayoutConstraint(item: mb, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute,multiplier: 1, constant: 414))
view.addConstraint(NSLayoutConstraint(item: mb, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute,multiplier: 1, constant: 64))
view.addConstraint(NSLayoutConstraint(item: mb, attribute: .left, relatedBy: .equal, toItem: self.bottomLayoutGuide, attribute: .left, multiplier: 1, constant: 0))
view.addConstraint(NSLayoutConstraint(item: mb, attribute: .right, relatedBy: .equal, toItem: self.bottomLayoutGuide, attribute: .right, multiplier: 1, constant: 0))
view.addConstraint(NSLayoutConstraint(item: mb, attribute: .bottom, relatedBy: .equal, toItem: self.bottomLayoutGuide, attribute: .bottom, multiplier: 1, constant: 0))
It's works for me in Swift 4.

Related

When added to a view, the constraint's items must be descendants of that view (or the view itself).

Here is my following code:
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let headerView = UIView()
headerView.backgroundColor = UIColor.white
let headerLabel = UILabel(frame: CGRect(x: 30, y: 0, width:
tableView.bounds.size.width, height: tableView.bounds.size.height))
headerLabel.font = UIFont().robotoMedium(withFontSize: 10)
headerLabel.textColor = CustomColor.lightGrey.color
headerLabel.text = "Travel Shops"
headerLabel.sizeToFit()
headerView.addSubview(headerLabel)
headerLabel.translatesAutoresizingMaskIntoConstraints = false
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .trailing, relatedBy: .equal, toItem: tableView, attribute: .trailing, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .leading, relatedBy: .equal, toItem: tableView, attribute: .leading, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .top, relatedBy: .equal, toItem: self.topLayoutGuide, attribute: .bottom, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 131))
return headerView
}
But the application crashes with the following:
When added to a view, the constraint's items must be descendants of that view (or the view itself). This will crash if the constraint needs to be resolved before the view hierarchy is assembled. Break on -[UIView(UIConstraintBasedLayout) _viewHierarchyUnpreparedForConstraint:] to debug.

headerLabel is child view of headerView and headerView is child of TableView in the hierarchy that is why this message is shown you need add the constraints to headerView which is the headerLabel.superView instead of UITableView which is headerLabel.superView.superView
Change your code
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .trailing, relatedBy: .equal, toItem: headerView, attribute: .trailing, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .leading, relatedBy: .equal, toItem: headerView, attribute: .leading, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .top, relatedBy: .equal, toItem: self.topLayoutGuide, attribute: .bottom, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 131))
by this one
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .trailing, relatedBy: .equal, toItem: tableView, attribute: .trailing, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .leading, relatedBy: .equal, toItem: headerView, attribute: .leading, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .top, relatedBy: .equal, toItem: headerView, attribute: .bottom, multiplier: 1, constant: 0))
headerLabel.addConstraint(NSLayoutConstraint(item: headerLabel, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 131))
Hope this helps

Xcode adds duplicate constraints?

In code I added 4 constraints. But when I run the app, in UI debugger, it shows additional 6 constraints? It should be all clear with these 4 I added. I don't know what I'm doing wrong?
let leftConstr = NSLayoutConstraint(item: image, attribute: .leading, relatedBy: .equal, toItem: cell.contentView, attribute: .leading, multiplier: 1.0, constant: 0.0)
let bottomConstr = NSLayoutConstraint(item: image, attribute: .bottom, relatedBy: .equal, toItem: cell.contentView , attribute: .bottom, multiplier: 1.0, constant: 0.0)
let highthConstr = NSLayoutConstraint(item: image, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 15)
let widthConstr = NSLayoutConstraint(item: image, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 50)
cell.contentView.addConstraints([highthConstr, widthConstr, bottomConstr, leftConstr])
Here is the screenshot of my UI debugger

Maybe you can try to add this line of code before :
image.translatesAutoresizingMaskIntoConstraints = false

Using auto layout at the expense of having no frame

I have a box that is initiated without a frame so it has 0 center and size.
let blackBox = UIView()
blackBox.backgroundColor = .blackColor()
blackBox.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(blackBox)
view.addConstraint(NSLayoutConstraint(item: blackBox, attribute: .Width, relatedBy: .Equal, toItem: view, attribute: .Width, multiplier: 0.1, constant: 0))
view.addConstraint(NSLayoutConstraint(item: blackBox, attribute: .Height, relatedBy: .Equal, toItem: view, attribute: .Height, multiplier: 0.5, constant: 0))
view.addConstraint(NSLayoutConstraint(item: blackBox, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: 0))
view.addConstraint(NSLayoutConstraint(item: blackBox, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: 0))
Is there anyway to insert a centered subview into the blackBox without using autolayout or is there a neater way I could/should use it. The only way I can see this happening is:
let blueBox = UIView()
blackBox.addSubview(blueBox)
blueBox.translatesAutoresizingMaskIntoConstraints = false
blueBox.backgroundColor = UIColor.blueColor()
view.addConstraint(NSLayoutConstraint(item: blueBox, attribute: .CenterX, relatedBy: .Equal, toItem: blackBox, attribute: .CenterX, multiplier: 1, constant: 0))
view.addConstraint(NSLayoutConstraint(item: blueBox, attribute: .CenterY, relatedBy: .Equal, toItem: blackBox, attribute: .CenterY, multiplier: 1, constant: 0))
view.addConstraint(NSLayoutConstraint(item: blueBox, attribute: .Width, relatedBy: .Equal, toItem: blackBox, attribute: .Width, multiplier: 0.4, constant: 0))
view.addConstraint(NSLayoutConstraint(item: blueBox, attribute: .Height, relatedBy: .Equal, toItem: blackBox, attribute: .Height, multiplier: 0.4, constant: 0))

I personally would use var bluebox = UIView(frame: CGRECT) and set the CGRect accordingly.

How to add a subview with constraints to make the subview with the same frame as its superview?

Within UIView I have a method presentView():
public func presentView() {
UIApplication.sharedApplication().delegate?.window??.addSubview(self)
let blurEffect = UIBlurEffect(style: .Light)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.backgroundColor = UIColor.yellowColor()
addSubview(blurEffectView)
let topConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Top, relatedBy: .Equal, toItem: self, attribute: .Bottom, multiplier: 1, constant: 0)
let bottomConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Bottom, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1, constant: 0)
let leadingConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Leading, relatedBy: .Equal, toItem: self, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 0)
let trailingConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Trailing, relatedBy: .Equal, toItem: self, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: 0)
self.addConstraints([topConstraint, bottomConstraint, leadingConstraint, trailingConstraint])
print("newframe: \(blurEffectView.frame)")
}
but sth is wrong because this is the output on console:
newframe: (0.0, 0.0, 0.0, 0.0)
and result is:

Remember about:
blurEffectView.translatesAutoresizingMaskIntoConstraints = false
and then:
let topConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Top, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1, constant: 0)
let bottomConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Bottom, relatedBy: .Equal, toItem: self, attribute: .Bottom, multiplier: 1, constant: 0)
let leadingConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Leading, relatedBy: .Equal, toItem: self, attribute: .Leading, multiplier: 1, constant: 0)
let trailingConstraint = NSLayoutConstraint(item: blurEffectView, attribute: .Trailing, relatedBy: .Equal, toItem: self, attribute: .Trailing, multiplier: 1, constant: 0)
addSubview(blurEffectView)
addConstraints([topConstraint, bottomConstraint, leadingConstraint, trailingConstraint])
layoutIfNeeded()

Swift NSlayoutConstraint

I have a question... I am really not understand something.
I have a UIView Class which only create a UITextLabel.. I'm trying to add instances from this class to my Viewcontroller. This is how my UIViewClass look like:
class PostLineItem: UIView {
var labelText : String!
var labelHeader : String!
init(labelText: String , labelHeader: String) {
super.init(frame: CGRect.zeroRect)
self.labelText = labelText
self.labelHeader = labelHeader
let tlb = timeLineBlock()
//tlb.setTranslatesAutoresizingMaskIntoConstraints(false)
self.addSubview(tlb)
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: tlb, attribute: .Height, relatedBy: .Equal, toItem: self, attribute: .Height, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Width, relatedBy: .Equal, toItem: self, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Left, relatedBy: .Equal, toItem: self, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Top, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1.0, constant: 0)
])
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
println("required public")
}
private func timeLineBlock() -> UIView{
let viewNew = UIView()
viewNew.setTranslatesAutoresizingMaskIntoConstraints(false)
let titleLabel = UILabel()
titleLabel.setTranslatesAutoresizingMaskIntoConstraints(false)
titleLabel.font = UIFont(name: "ArialMT", size: 20)
titleLabel.textColor = UIColor.blackColor()
titleLabel.text = labelHeader
titleLabel.numberOfLines = 0
viewNew.addSubview(titleLabel)
titleLabel.backgroundColor = UIColor.redColor()
/* IF I NOT COMMENT THIS PART INSTANCE OF THIS CLASS IS NOT SHOWING UP.
viewNew.addConstraints([
NSLayoutConstraint(item: titleLabel, attribute: .Width, relatedBy: .Equal, toItem: viewNew, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: titleLabel, attribute: .Left, relatedBy: .Equal, toItem: viewNew, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: titleLabel, attribute: .Top, relatedBy: .Equal, toItem: viewNew, attribute: .Top, multiplier: 1.0, constant: 0)
])
*/
viewNew.backgroundColor = UIColor.greenColor()
return viewNew
}
}
And this is my viewController class part where i try to instantiate the PostLineItem instances..
let guideView = UIView()
guideView.setTranslatesAutoresizingMaskIntoConstraints(false)
guideView.backgroundColor = UIColor.blackColor()
scrollView.addSubview(guideView)
scrollView.addConstraints([
NSLayoutConstraint(item: guideView, attribute: .Top, relatedBy: .Equal, toItem: scrollView, attribute: .Top, multiplier: 1.0, constant: 50),
NSLayoutConstraint(item: guideView, attribute: .Left, relatedBy: .Equal, toItem: scrollView, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: guideView, attribute: .Width, relatedBy: .Equal, toItem: scrollView, attribute: .Width, multiplier: 1.0, constant: -30),
NSLayoutConstraint(item: guideView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant:10)
])
guideView.backgroundColor = UIColor.blackColor()
var viewFromAbove = guideView
for post in 1...70 {
let v = PostLineItem(labelText: "Tst", labelHeader: "Tst2")
scrollView.addSubview(v)
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: v, attribute: .Top, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Bottom, multiplier: 1.0, constant: 15),
NSLayoutConstraint(item: v, attribute: .Left, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: v, attribute: .Width, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: v, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1.0, constant: 400)
])
viewFromAbove = v
}
scrollView.addConstraints([
NSLayoutConstraint(item: viewFromAbove, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: scrollView, attribute: NSLayoutAttribute.Bottom, multiplier: 1.0, constant: -10)
])
As you can see, first of all i create a guidview for the first PostLineItem and then adding the new instances and the constraints.. So..
If i do it this way the instances of the PostLineItem class will be at the same places and hides each others... I think, the NSLAyoutConstaint not effect.
But, as you can see at the commented part of the code, if i create a simple UILabel the constraints work fine, and all of the UILabel instances will be under each others..
UPDATE:
after i adding all of written in the answer it's look like this.. :(
That little red rect is my PostLineItem instance.. :(
UPDATED - all code.

I'm thinking you might be adding the constraints to the wrong views. For instance, the guideView height constraint should be added to the guideView, and not the scrollView. I would suggest instead you use the new way of activating constraints. Instead of adding them to the views, you just call the activateConstraints class method on NSLayoutConstraint:
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: guideView, attribute: .Top, relatedBy: .Equal, toItem: scrollView, attribute: .Top, multiplier: 1.0, constant: 24),
NSLayoutConstraint(item: guideView, attribute: .Left, relatedBy: .Equal, toItem: scrollView, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: guideView, attribute: .Width, relatedBy: .Equal, toItem: scrollView, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: guideView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant:4)
])
and
NSLayoutConstraints.activateConstraints([
NSLayoutConstraint(item: v, attribute: .Top, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Bottom, multiplier: 1.0, constant: 5),
NSLayoutConstraint(item: v, attribute: .Left, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: v, attribute: .Width, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Width, multiplier: 1.0, constant: 0),
])
Also, you are missing a constraint for the height of your PostLineItem, something like:
NSLayoutConstraint(item: v, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant:10)
In your PostLineItem init, you need to add constraints for the timeLineBlock:
init(labelText: String , labelHeader: String) {
super.init(frame: CGRect.zeroRect)
self.labelText = labelText
self.labelHeader = labelHeader
let tlb = timeLineBlock()
self.addSubview(tlb)
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: tlb, attribute: .Height, relatedBy: .Equal, toItem: self, attribute: .Height, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Width, relatedBy: .Equal, toItem: self, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Left, relatedBy: .Equal, toItem: self, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Top, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1.0, constant: 0)
])
}
Here is my version. I'm getting much better results. Take a look... Note, I set up my scrollView entirely in Interface Builder and just added an outlet called scrollView that points to the contentView contained by my scrollView. That shouldn't matter. Everything else is as you implemented.
class PostLineItem: UIView {
var labelText : String!
var labelHeader : String!
init(labelText: String , labelHeader: String) {
super.init(frame: CGRect.zeroRect)
self.labelText = labelText
self.labelHeader = labelHeader
let tlb = timeLineBlock()
self.addSubview(tlb)
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: tlb, attribute: .Height, relatedBy: .Equal, toItem: self, attribute: .Height, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Width, relatedBy: .Equal, toItem: self, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Left, relatedBy: .Equal, toItem: self, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: tlb, attribute: .Top, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1.0, constant: 0)
])
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
println("required public")
}
private func timeLineBlock() -> UIView{
let viewNew = UIView()
viewNew.setTranslatesAutoresizingMaskIntoConstraints(false)
let titleLabel = UILabel()
titleLabel.setTranslatesAutoresizingMaskIntoConstraints(false)
titleLabel.font = UIFont(name: "ArialMT", size: 20)
titleLabel.textColor = UIColor.blackColor()
titleLabel.text = labelHeader
titleLabel.numberOfLines = 0
viewNew.addSubview(titleLabel)
titleLabel.backgroundColor = UIColor.redColor()
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: titleLabel, attribute: .Width, relatedBy: .Equal, toItem: viewNew, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: titleLabel, attribute: .Left, relatedBy: .Equal, toItem: viewNew, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: titleLabel, attribute: .Top, relatedBy: .Equal, toItem: viewNew, attribute: .Top, multiplier: 1.0, constant: 0)
])
viewNew.backgroundColor = UIColor.greenColor()
return viewNew
}
}
class ViewController: UIViewController {
#IBOutlet weak var scrollView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
let guideView = UIView()
guideView.setTranslatesAutoresizingMaskIntoConstraints(false)
guideView.backgroundColor = UIColor.blackColor()
scrollView.addSubview(guideView)
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: guideView, attribute: .Top, relatedBy: .Equal, toItem: scrollView, attribute: .Top, multiplier: 1.0, constant: 24),
NSLayoutConstraint(item: guideView, attribute: .Left, relatedBy: .Equal, toItem: scrollView, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: guideView, attribute: .Width, relatedBy: .Equal, toItem: scrollView, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: guideView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant:4)
])
guideView.backgroundColor = UIColor.blackColor()
var viewFromAbove = guideView
for post in 1...70 {
let v = PostLineItem(labelText: "Tst", labelHeader: "Tst2")
//let v = UILabel(frame: CGRectMake(0, 0, 10, 10))
//v.text = "Tst Now with this its working, and the constraint is fine."
v.setTranslatesAutoresizingMaskIntoConstraints(false)
scrollView.addSubview(v)
NSLayoutConstraint.activateConstraints([
NSLayoutConstraint(item: v, attribute: .Top, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Bottom, multiplier: 1.0, constant: 5),
NSLayoutConstraint(item: v, attribute: .Left, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Left, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: v, attribute: .Width, relatedBy: .Equal, toItem: viewFromAbove, attribute: .Width, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: v, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant:30)
])
viewFromAbove = v
}
}
}

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