I've got a problem where I have prototype cell with 6 labels on it and after that I have random number of views with picture on left side and text on right side as it is on Picture 1.
I tried to make a xib file which represents view with picture and label and constraints on it Picture 2.
Then I tried to make that view and add it with constraints to cell. It looks like constraints are totally wrong. This is how I tried to set constraints:
for (index, entity) in linkedEntities.enumerate() {
let linkedEntityView: LinkedEntityInExtendedSearchNotes = UIView.fromNib()
linkedEntityView.entity = entity
addSubview(linkedEntityView)
linkedEntityView.translatesAutoresizingMaskIntoConstraints = false
print(self.dynamicType)
if index == 0 {
let verticalSpace = NSLayoutConstraint(item: linkedEntityView, attribute: .Top, relatedBy: .Equal, toItem: noteTextLabel, attribute: .Bottom, multiplier: 1, constant: 8)
let leading = NSLayoutConstraint(item: linkedEntityView, attribute: .Leading, relatedBy: .Equal, toItem: self, attribute: .LeadingMargin, multiplier: 1, constant: 8)
let trailing = NSLayoutConstraint(item: linkedEntityView, attribute: .Trailing, relatedBy: .Equal, toItem: self, attribute: .Trailing, multiplier: 1, constant: 8)
NSLayoutConstraint.activateConstraints([verticalSpace, leading, trailing])
} else if index > 0 && index < linkedEntities.count - 1 {
let verticalSpace = NSLayoutConstraint(item: linkedEntityView, attribute: .Top, relatedBy: .Equal, toItem: previousView, attribute: .Bottom, multiplier: 1, constant: 8)
let leading = NSLayoutConstraint(item: linkedEntityView, attribute: .Leading, relatedBy: .Equal, toItem: self, attribute: .Leading, multiplier: 1, constant: 8)
let trailing = NSLayoutConstraint(item: linkedEntityView, attribute: .Trailing, relatedBy: .Equal, toItem: self, attribute: .Trailing, multiplier: 1, constant: 8)
NSLayoutConstraint.activateConstraints([verticalSpace, leading, trailing])
} else {
let verticalSpace = NSLayoutConstraint(item: linkedEntityView, attribute: .Top, relatedBy: .Equal, toItem: previousView, attribute: .Bottom, multiplier: 1, constant: 8)
let leading = NSLayoutConstraint(item: linkedEntityView, attribute: .Leading, relatedBy: .Equal, toItem: self, attribute: .LeadingMargin, multiplier: 1, constant: 8)
let trailing = NSLayoutConstraint(item: linkedEntityView, attribute: .Trailing, relatedBy: .Equal, toItem: self, attribute: .Trailing, multiplier: 1, constant: 8 )
let bottomSpace = NSLayoutConstraint(item: linkedEntityView, attribute: .BottomMargin, relatedBy: .Equal, toItem: self, attribute: .Bottom, multiplier: 1, constant: 8)
NSLayoutConstraint.activateConstraints([verticalSpace, leading, trailing, bottomSpace])
}
previousView = linkedEntityView
}
noteTextLabel is last label before repetitive content. Where I'm wrong with constraints? Is there any other (better) way to put repeatable content to prototype cell?
Thanks.
Related
Example
Has anyone got an example of doing something like that?
I want it to be displayed all the time while passing between other controllers. I do not want to create it again in every controller.
Override TabBar controller's view did load, to create your beamView:
let beamViewHeight:CGFloat = 60
let beamView = UIView()
beamView.translatesAutoresizingMaskIntoConstraints = false
beamView.backgroundColor = .black
self.view.addSubview(beamView)
add constraint to align it bottom, top of the tab bar:
let bottom = NSLayoutConstraint(item: beamView, attribute: .bottom, relatedBy: .equal, toItem: self.tabBar, attribute: .top, multiplier: 1, constant: 0)
let leading = NSLayoutConstraint(item: beamView, attribute: .leading, relatedBy: .equal, toItem: view, attribute: .leading, multiplier: 1, constant: 0)
let trailing = NSLayoutConstraint(item: beamView, attribute: .trailing, relatedBy: .equal, toItem: view, attribute: .trailing, multiplier: 1, constant: 0)
let height = NSLayoutConstraint(item: beamView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: beamViewHeight)
view.addConstraints([bottom, leading, trailing, height])
it look's like this:
I have an app which is downloading image from server by clicking the button. After image have downloaded i create a new imageView and add it to the my contentView(UIView). I need to create the constraints - every new imageview need top constraint from previous one
func addNewImageToTheScrollView(img: UIImage?) {
if let imageResponse = img {
let imageView = UIImageView(image: imageResponse.crop(rect: CGRect(x: 0, y: imageResponse.size.height/2, width: self.contentView.frame.width, height: 200)))
self.contentView.addSubview(imageView)
imageView.translatesAutoresizingMaskIntoConstraints = false
let x = NSLayoutConstraint(item: imageView, attribute: .centerX, relatedBy: .equal, toItem: self.contentView, attribute: .centerX, multiplier: 1.0, constant: 0)
let y = NSLayoutConstraint(item: imageView, attribute: .top, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 30)
let width = NSLayoutConstraint(item: imageView, attribute: .width, relatedBy: .equal, toItem: self.contentView, attribute: .width, multiplier: 1.0, constant: 0)
let height = NSLayoutConstraint(item: imageView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150)
self.contentView.addConstraints([x, y])
imageView.addConstraints([width, height])
}
}
If i comment the constraint code, it will be work fine unless every new imageView will be on the same place, on the top of the View. Now whit this constraint code i have such code issue after downloading
2017-07-02 14:50:01.018 ImageFromServerTest[11516:1080948] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'NSLayoutConstraint for >: A multiplier of 0 or a nil second item together with a location for the first attribute creates an illegal constraint of a location equal to a constant. Location attributes must be specified in pairs.'
Whenever you are working with scrollViews, there are 2 thumb rules for it:-
Give the scrollView leading, trailing, bottom, and top constraint with respect to the superview, that is self.view
#IbOutlet weak var scrollView: UIScrollView!
let leading = NSLayoutConstraint(item: scrollView, attribute: .leading, relatedBy: .equal, toItem: self.view, attribute: .leadingMargin, multiplier: 1.0, constant: 0)
let trailing = NSLayoutConstraint(item: scrollView, attribute: .trailing, relatedBy: .equal, toItem: self.view, attribute: .trailingMargin, multiplier: 1.0, constant: 0)
let top = NSLayoutConstraint(item: scrollView, attribute: .top, relatedBy: .equal, toItem: self.view, attribute: .top, multiplier: 1.0, constant: 0)
let bottom = NSLayoutConstraint(item: scrollView, attribute: .bottom, relatedBy: .equal, toItem: self.view, attribute: .bottom, multiplier: 1.0, constant: 0)
Add constraints to the contentView with respect to the scrollView
#IbOutlet weak var contentView: UIView!
let leading = NSLayoutConstraint(item: contentView, attribute: .leading, relatedBy: .equal, toItem: scrollView, attribute: .leading, multiplier: 1.0, constant: 0)
let trailing = NSLayoutConstraint(item: contentView, attribute: .trailing, relatedBy: .equal, toItem: scrollView, attribute: .trailing, multiplier: 1.0, constant: 0)
let top = NSLayoutConstraint(item: contentView, attribute: .top, relatedBy: .equal, toItem: scrollView, attribute: .top, multiplier: 1.0, constant: 0)
//increase the constant according to how much long you need the scrollview to be
let bottom = NSLayoutConstraint(item: contentView, attribute: .bottom, relatedBy: .equal, toItem: scrollView, attribute: .bottom, multiplier: 1.0, constant: 0)
Now add your subviews constraints (labels, images) with respect to the contentView
For example- You received your first image, so we will maintain an array of UIImageViews outside your function.
var imageViews = [UIImageViews]() //declared outside the function
//received an image here
var imageView = UIImageView() // define the frame according to yourself using frame init method
imageView.image = image
if imageViews.isEmpty { // first image view
//add constraints to first image view
let x = NSLayoutConstraint(item: imageView, attribute: .centerX, relatedBy: .equal, toItem: contentView, attribute: .centerX, multiplier: 1.0, constant: 0)
let y = NSLayoutConstraint(item: imageView, attribute: .top, relatedBy: .equal, toItem: contentView, attribute: .top, multiplier: 1.0, constant: 30)
let width = NSLayoutConstraint(item: imageView, attribute: .width, relatedBy: .equal, toItem: self.contentView, attribute: .width, multiplier: 1.0, constant: 0)
let height = NSLayoutConstraint(item: imageView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150)
}
else { //second, third, fourth image view... so on
let x = NSLayoutConstraint(item: imageView, attribute: .centerX, relatedBy: .equal, toItem: contentView, attribute: .centerX, multiplier: 1.0, constant: 0)
let y = NSLayoutConstraint(item: imageView, attribute: .top, relatedBy: .equal, toItem: imageViews[imageViews.count - 1], attribute: .bottom, multiplier: 1.0, constant: 30)
let width = NSLayoutConstraint(item: imageView, attribute: .width, relatedBy: .equal, toItem: self.contentView, attribute: .width, multiplier: 1.0, constant: 0)
let height = NSLayoutConstraint(item: imageView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150)
}
imageViews.append(imageView)
}
Hope you got an idea now, how to proceed with this problem. If having more than 4 or 5 imageviews, you'll probably want to check the count of the array and increase the contentView of the scrollView accordingly. you can do so by using
self.scrollView.contentSize = CGSize(width, height)
I believe you have a problem here:
let y = NSLayoutConstraint(item: imageView, attribute: .top, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 30)
"toItem" parameter should have some value. Also first parameter should be imageView.topAnchor. Probably it should look something like this:
let y = NSLayoutConstraint(item: imageView.topAnchor, attribute: .top, relatedBy: .equal, toItem: self.contentView.topAnchor, attribute: .notAnAttribute, multiplier: 1.0, constant: 30)
I know this is a hard problem to debug. I will try to explain, you can ask question from comments section.
I want to use message bubbles in my app. I wrote some code for constraints, but it is not working well.
How can i put the left edge of blue bubble to red line?
Here is my code:
When tableview cell loads this method is running:
private func setup() {
bubbleImageView = UIImageView(image: bubbleImage.incoming, highlightedImage: bubbleImage.incomingHighlighed)
bubbleImageView.userInteractionEnabled = true
messageLabel = UILabel(frame: CGRectZero)
messageLabel.font = UIFont.systemFontOfSize(15)
messageLabel.numberOfLines = 0
messageLabel.userInteractionEnabled = true
selectionStyle = .None
contentView.addSubview(bubbleImageView)
bubbleImageView.addSubview(messageLabel)
messageLabel.translatesAutoresizingMaskIntoConstraints = false
bubbleImageView.translatesAutoresizingMaskIntoConstraints = false
contentView.addConstraint(NSLayoutConstraint(item: bubbleImageView, attribute: .Left, relatedBy: .Equal, toItem: contentView, attribute: .Left, multiplier: 1, constant: 10))
contentView.addConstraint(NSLayoutConstraint(item: bubbleImageView, attribute: .Top, relatedBy: .Equal, toItem: contentView, attribute: .Top, multiplier: 1, constant: 4.5))
bubbleImageView.addConstraint(NSLayoutConstraint(item: bubbleImageView, attribute: .Width, relatedBy: .Equal, toItem: messageLabel, attribute: .Width, multiplier: 1, constant: 30))
contentView.addConstraint(NSLayoutConstraint(item: bubbleImageView, attribute: .Bottom, relatedBy: .Equal, toItem: contentView, attribute: .Bottom, multiplier: 1, constant: -4.5))
bubbleImageView.addConstraint(NSLayoutConstraint(item: messageLabel, attribute: .CenterX, relatedBy: .Equal, toItem: bubbleImageView, attribute: .CenterX, multiplier: 1, constant: -2))
bubbleImageView.addConstraint(NSLayoutConstraint(item: messageLabel, attribute: .CenterY, relatedBy: .Equal, toItem: bubbleImageView, attribute: .CenterY, multiplier: 1, constant: -0.5))
messageLabel.preferredMaxLayoutWidth = 218
bubbleImageView.addConstraint(NSLayoutConstraint(item: messageLabel, attribute: .Height, relatedBy: .Equal, toItem: bubbleImageView, attribute: .Height, multiplier: 1, constant: -15))
}
As you can see i am creating bubble background and label for text.
And second method:
func setCell(message:Message) {
messageLabel.text="testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttest"
var layoutAttribute: NSLayoutAttribute
var layoutConstant: CGFloat
if message.incoming {
bubbleImageView.image=bgImage.incoming
messageLabel.textColor = UIColor.blackColor()
layoutAttribute = .Left
layoutConstant = 10
}else{
if message.isSent == 1 {
bubbleImageView.image = bgImage.outgoing
}
if message.isSent == 0 {
bubbleImageView.image = bgImage.notYetSent
}
messageLabel.textColor = UIColor.whiteColor()
layoutAttribute = .Right
layoutConstant = -10
}
contentView.addConstraint(NSLayoutConstraint(item: bubbleImageView, attribute: layoutAttribute, relatedBy: .Equal, toItem: contentView, attribute: layoutAttribute, multiplier: 1, constant: layoutConstant))
}
What is the problem with my code? It is working well for incoming messages (gray bubble) and not working well for outgoing messages (blue bubble)
I get it. You have to add a constraint that doesnt allows the bubble to exceed the max width. So you have to add a constraint like that:
let widthConstraint = NSLayoutConstraint(item: youritem, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.LessThanOrEqual,
toItem: self.youItem.superview, attribute: NSLayoutAttribute.Width,
multiplier: 1.0, constant: 100)
The Following are the constraints that am using.
<NSLayoutConstraint:0x7fcfdd405bc0 UILabel:0x7fcfdd405780'ACTIVITY'.centerY == UIView:0x7fcfdb677b60.centerY>The view hierarchy is not prepared for the constraint:
footer!.frame = CGRectMake(0, 0, tableView.frame.size.width, FOOTER_HEIGHT)
let activityLabel = UILabel()
activityLabel.text = "SomeText"
activityLabel.translatesAutoresizingMaskIntoConstraints = false
let CenterConstraint = NSLayoutConstraint(item: activityLabel, attribute: .CenterX, relatedBy: .Equal, toItem: footerView, attribute: .CenterX, multiplier: 1, constant: 0)
let CenterConstraint = NSLayoutConstraint(item: activityLabel, attribute: .CenterY, relatedBy: .Equal, toItem: footerView, attribute: .CenterY, multiplier: 1, constant: 0)
footer!.addConstraints([xxCenterConstraint,yyCenterConstraint])
footer!.addSubview(activityLabel)
let notificationLabel = UILabel()
notificationLabel.text = "9"
notificationLabel.textAlignment = .Center
notificationLabel.backgroundColor = customBlueColor
footerView!.addSubview(notificationLabel)
notificationLabel.translatesAutoresizingMaskIntoConstraints = false
let width = NSLayoutConstraint(item: notificationLabel, attribute: .Width, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: NOTIFICATION_LABEL_HEIGHT)
let height = NSLayoutConstraint(item: notificationLabel, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: NOTIFICATION_LABEL_HEIGHT)
let yCenterConstraint = NSLayoutConstraint(item: notificationLabel, attribute: .CenterY, relatedBy: .Equal, toItem: footerView, attribute: .CenterY, multiplier: 1, constant: 0)
let leadingConstraint1 = NSLayoutConstraint(item: activityLabel, attribute: .Trailing, relatedBy: .Equal, toItem: notificationLabel, attribute: .Leading, multiplier: 1, constant:-LEADING_SPACE)
footer!.addConstraints([width,height,yCenterConstraint,leadingConstraint1])
notificationLabel.layer.cornerRadius = NOTIFICATION_LABEL_HEIGHT/2
notificationLabel.clipsToBounds = true
You can't add constraints before the views are part of the same view hierarchy. Move the addSubview line before the addConstraints line.
I'm trying to programmatically create a UIView with a UILabel as a subview using autolayout.
Constraints
I used the following constraints on view:
CenterX of view to fastAttacksContainerView (superview).
Top constraint of constant 8 to superview.
Then created a label which is a subview of view and added constraints of constant 8 for Top, Bottom, Left, and Right to view.
Problem
The view only resizes to the frame of the label and does not account for the 4 constraints of constant 8 on all 4 sides. Which causes the label to be displayed partially outside the view.
let view = UIView()
view.backgroundColor = pokemon.secondaryColor
let label = UILabel()
fastAttacksContainerView.addSubview(view)
view.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(label)
label.translatesAutoresizingMaskIntoConstraints = false
label.text = fa
let gest = UITapGestureRecognizer(target: self, action: #selector(self.selectFastAttack))
view.addGestureRecognizer(gest)
fastAttackButtons.append(view)
fastAttackLables.append(label)
let top = NSLayoutConstraint(item: view, attribute: .Top, relatedBy: .Equal, toItem: fastAttacksContainerView, attribute: .Top, multiplier: 1, constant: 8)
let centerX = NSLayoutConstraint(item: view, attribute: .CenterX, relatedBy: .Equal, toItem: fastAttacksContainerView, attribute: .CenterX, multiplier: 1, constant: 0)
let labLeft = NSLayoutConstraint(item: label, attribute: .Left, relatedBy: .Equal, toItem: view, attribute: .Left, multiplier: 1, constant: 8)
let labTop = NSLayoutConstraint(item: label, attribute: .Top, relatedBy: .Equal, toItem: view, attribute: .Top, multiplier: 1, constant: 8)
let labRigth = NSLayoutConstraint(item: label, attribute: .Right, relatedBy: .Equal, toItem: view, attribute: .Right, multiplier: 1, constant: 8)
let labBottom = NSLayoutConstraint(item: label, attribute: .Bottom, relatedBy: .Equal, toItem: view, attribute: .Bottom, multiplier: 1, constant: 8)
view.addConstraints([labLeft, labTop, labRigth, labBottom])
fastAttacksContainerView.addConstraints([top, centerX])
Output
view has ambiguous height.
You should add constraint for height of view or distance from it to bottom of fastAttacksContainerView.
I managed to fix this problem by making a similar setup on storyboard and copying the constraints in.
Things that I changed:
Used Leading and Trailing instead of Left and Right layout attributes.
For the labLeft and labRight constraints, I interchanged item and toItem. (This seems like a bug to me. Can anyone verify, please?)
Code change:
let labLeft = NSLayoutConstraint(item: label, attribute: .Leading, relatedBy: .Equal, toItem: view, attribute: .Leading, multiplier: 1, constant: 8)
let labTop = NSLayoutConstraint(item: label, attribute: .Top, relatedBy: .Equal, toItem: view, attribute: .Top, multiplier: 1, constant: 8)
let labRigth = NSLayoutConstraint(item: view, attribute: .Trailing, relatedBy: .Equal, toItem: label, attribute: .Trailing, multiplier: 1, constant: 8)
let labBottom = NSLayoutConstraint(item: view, attribute: .Bottom, relatedBy: .Equal, toItem: label, attribute: .Bottom, multiplier: 1, constant: 8)