Is there anyway to create a custom alertController that fit the width of the screen ?
I tried several things before asking this question
one of them is :
let width:NSLayoutConstraint = NSLayoutConstraint(item: alertController.view, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: view.bounds.width )
alertController.view.addConstraint(width)
But this line of code always makes a horizontal space between my alertController and the Screen.
Here is what I currently find in the Apple documents:
Appearance of Alert Views:
You cannot customize the appearance of alert views.
This disappoints me as I think the message text in alert views is too small for many users. DrPatience, in a comment above, suggests a possible workaround.
Alert Views
Related
I have a viewController holding a constraint like this one:
self.subviewConstraint = NSLayoutConstraint(item: self.subviewConstraint,
attribute: .bottom,
relatedBy: .equal,
toItem: self.bottomLayoutGuide,
attribute: .bottom,
multiplier: 1,
constant: 0)
and I'm being shown this warning:
'bottomLayoutGuide' was deprecated in iOS 11.0: Use view.safeAreaLayoutGuide.bottomAnchor instead of bottomLayoutGuide.topAnchor
I'm only finding examples for setting anchors instead of NSLayoutConstraints like this, and I don't fully understand this warning... "use view.safeAreaLayoutGuide.bottomAnchor instead of bottomLayoutGuide.topAnchor"? How is that the bottom anchor of the safeAreaLayoutGuide matches the top anchor of the of the bottomLayoutGuide? Where could I find a good graphical explanation of this?
How should I correctly rewrite my constraint to keep its current behaviour?
TopLayoutGuide and bottomLayoutGuide are deprecated since iOS 11.
You could update your code with this, taking advantage of the new NSLayoutAnchor:
self.subviewConstraint = self.subviewConstraint?.firstItem?.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)
or you can use the initializer of NSLayoutConstraint as in your question:
self.subviewConstraint = NSLayoutConstraint(item: self.subviewConstraint?.firstItem as Any,
attribute: .bottom,
relatedBy: .equal,
toItem: view.safeAreaLayoutGuide,
attribute: .bottom,
multiplier: 1,
constant: 0)
Note that I've changed your self.subviewConstraint parameter to self.subviewConstraint.firstItem instead, within the NSLayoutConstraint initialization method, because you were using the NSLayoutConstraint as the item.
I suppose this is some kind of typo you made.
Here you can find some good graphical explanation of the new SafeArea behaviour in iOS 11 and above:
iOS Safe Area - Medium.com
Additionally, you said "I'm only finding examples for setting anchors instead of NSLayoutConstraints", but I want to make it clear that the constraint(equalTo:) method of NSLayoutAnchor returns an NSLayoutConstraint. (Apple NSLayoutAnchor documentation)
i have one view.xib file and it's having small container(container view) which holds all the controls like button/textfield, all the events of controls is handle by parent view.xib class file.
My requirement is at one place i need to add/show parent i.e view.xib completed screen. At one more place i need to add only container view. when i add/show container view only, control's associated events/methods doesn't works.
So i thought, if i can change class of container view with parent view.xib's class, my work can be done.
so either suggest me some other solutions or class swizzaling if it's possible to handle in this way.
basically i am adding container view on uitableview cell's container(view) my code for same is as below
if let questionContainerView = cellQuestionView.viewQuestionContainer {
// let questionContainerView = cellQuestionView
cell.viewQuestionContainer.addSubview(questionContainerView)
questionContainerView.translatesAutoresizingMaskIntoConstraints = false
cell.viewQuestionContainer.addConstraint(NSLayoutConstraint(item: questionContainerView, attribute: NSLayoutAttribute.left, relatedBy: NSLayoutRelation.equal, toItem: cell.viewQuestionContainer, attribute: NSLayoutAttribute.left, multiplier: 1, constant: 0))
cell.viewQuestionContainer.addConstraint(NSLayoutConstraint(item: questionContainerView, attribute: NSLayoutAttribute.right, relatedBy: NSLayoutRelation.equal, toItem: cell.viewQuestionContainer, attribute: NSLayoutAttribute.right, multiplier: 1, constant: 0))
cell.viewQuestionContainer.addConstraint(NSLayoutConstraint(item: questionContainerView, attribute: NSLayoutAttribute.top, relatedBy: NSLayoutRelation.equal, toItem: cell.viewQuestionContainer, attribute: NSLayoutAttribute.top, multiplier: 1, constant: 0))
cell.viewQuestionContainer.addConstraint(NSLayoutConstraint(item: questionContainerView, attribute: NSLayoutAttribute.bottom, relatedBy: NSLayoutRelation.equal, toItem: cell.viewQuestionContainer, attribute: NSLayoutAttribute.bottom, multiplier: 1, constant: 0))
cellQuestionView.layoutIfNeeded()
}
I believe what you are trying to do is create a re-usable UIView with your control buttons, that you can use in different view controllers. There is a great tutorial on Youtube entitled iOS Basically: Reusable UIView - Programming in Swift (Part 1).
Basically, you will want to create a .Xib file dedicated to the view that you want to re-use, with all the actions handled by that custom view class. Every time you will want your custom view, you will need to instantiate it from the Xib file and manually add it as a subview onto the container view.
Good luck and happy coding!
-- edit --
Your updated code shows that this will be part of a UITableView and you are trying to add your custom view on top of a UITableViewCell. You should instead instantiate a custom UITableViewCell and register it as reusable with the table view. This tutorial should guide you on doing just that: Custom UITableViewCell Tutorial - TableView with Images and Text in Swift
You can define your #IBAction in your custom table cell, and attach your button selectors to your action in your custom cell's nib.
Cheers!
If there are multiple UILabels in one UIStoryboard, and they have the same centerY, which means they are at the same line. How can I use autolayout to let them fit in different screen? I hope these UILabels have same font size.
You need to add constraints. There are a couple of ways to add constraints.
If you go to the storyboard you will see a rectangle in between 2 vertical lines. If you click the the view you want to add constraints too (Like the UIView you added) and click that rectangle box thing It gives you options to add constants to the left, right, top, bottom of the view. If you click on the dropdown menu it gives you a list of views around the view your adding constraints too so that you can add constraints relative to that view.
Another way to add constraints is clicking the triangle button in between 2 vertical lines and selecting the option "add missing constraints". Auto layout will then try and determine the best constraints to add automatically.
To delete or modify constraints you can click the "show size inspector" (looks like a ruler) and in the constraints section you should see some constraints if you have added any. You can click and delete them or edit them.
Another option is adding constraints programmatically (below is an example of adding constraints to an image view in a stack view in swift):
let trailingConstraint = NSLayoutConstraint(item: imageView, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: self.stackView, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: -5)
let leadingConstraint = NSLayoutConstraint(item: imageView, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: self.stackView, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 5)
self.stackView.addArrangedSubview(imageView)
self.stackView.addConstraint(trailingConstraint)
self.stackView.addConstraint(leadingConstraint)
I'm an Android developer trying my hand at Xcode and it's been unpleasant so far. What I'm trying to do is have a custom view that has three sub views:
UIImageView (for an icon)
UILabel (for the title)
UILabel (for the content)
I want it such that the content label's height grows and shrinks to wrap the text it contains (like Android's wrap_content). And then, I want the custom view to also grow and shrink to wrap all three sub views.
However, I cannot, for the life of me, figure out how these auto layouts/constraints work.
01) How would I make my UILabel's height grow/shrink to match its contained text?
02) How would I make my custom view's height grow/shrink to match its contained sub views?
override func layoutSubviews() {
super.layoutSubviews()
img_icon = UIImageView()
txt_title = UILabel()
txt_content = UILabel()
img_icon.backgroundColor = Palette.white
img_icon.image = icon
txt_title.text = title
txt_title.textAlignment = .Center
txt_title.font = UIFont(name: "Roboto-Bold", size:14)
txt_title.textColor = Palette.txt_heading1
txt_content.text = content
txt_content.textAlignment = .Center
txt_content.font = UIFont(name: "Roboto-Regular", size:12)
txt_content.textColor = Palette.txt_dark
txt_content.numberOfLines = 0
txt_content.preferredMaxLayoutWidth = self.frame.width
txt_content.lineBreakMode = NSLineBreakMode.ByWordWrapping
self.backgroundColor = Palette.white
addSubview(img_icon)
addSubview(txt_title)
addSubview(txt_content)
/*snip img_icon and txt_title constraints*/
let txt_content_x = NSLayoutConstraint(item: txt_content, attribute: .CenterX, relatedBy: .Equal, toItem: self, attribute: .CenterX, multiplier: 1, constant: 0)
let txt_content_y = NSLayoutConstraint(item: txt_content, attribute: .Top, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1, constant: 80)
let txt_content_w = NSLayoutConstraint(item: txt_content, attribute: .Width, relatedBy: .Equal, toItem: self, attribute: .Width, multiplier: 1, constant: 0)
let txt_content_h = NSLayoutConstraint(item: txt_content, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 40)
txt_content.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activateConstraints([
txt_content_x,
txt_content_y,
txt_content_w,
txt_content_h
])
}
I understand that, in the above code I've tried, I have the height set to a constant 40. This is only because I don't know how to achieve what I want.
[EDIT]
I've tried setting the height constraint to greater than or equal to but it just crashes Xcode.
[EDIT]
It crashes Xcode if I try to view it but works perfectly fine in the simulator. Question now is, why?
My height constraint is now:
let txt_content_h = NSLayoutConstraint(item: txt_content, attribute: .Height, relatedBy: .GreaterThanOrEqual, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 40)
It works in the simulator and has the desired behaviour. However, if I open the storyboard that contains the view, it crashes. It's definitely that line of code because changing it back to .Equal resolves the crash.
[EDIT]
My temporary fix is:
#if TARGET_INTERFACE_BUILDER
//use .Equal for height constraint
#else
//use .GreaterThanOrEqual for height constraint
#endif
This way, it doesn't crash Xcode and still renders the way I want it on the simulator.
[EDIT]
I removed the pre-processor check because I realized there's no actual thing like that defined and it still works now. I swear I've changed nothing else.
I am this close to giving up on iOS development because the interface builder keeps crashing Xcode without a reason when everything works in the simulator. Then, I do some nonsense edits and it works fine again.
01) How would I make my UILabel's height grow/shrink to match its contained text?
Just set top, left and right-constraint to the labels superview. Set the property number of lines to 0. Then it will start wrapping text.
02) How would I make my custom view's height grow/shrink to match its contained sub views?
By using interface builder this is much easier to achieve.
My suggestion to you is to start with your constraints in storyboard. You will not need to compile your code to see what the constraints will result in. Also you will get warnings and errors directly in the interface builder.
If you WANT to use programmatic constraints, my suggestion is to start using a framework for it. For example: https://github.com/SnapKit/SnapKit
You can use a trick with constraints to achieve wrap-content. For example :
let maximumWidth = frame / 4 //For example
yourView.widthAnchor.constraint(lessThanOrEqualToConstant: maximumWidth).isActive = true
The "maximumWidth" depends on your UI and your design and you can change it.
Also, you should set "lineBreakMode" in StoryBoard or in code like :
yourBtn.titleLabel?.lineBreakMode = .byCharWrapping //For UIButton or
yourTxt.textContainer.lineBreakMode = .byCharWrapping //For UITextView
Often clean will do a lot of good when code jams for no reason ar all, cmd-shift-k if i remember correctly
I understand there is no direct application of wrap content in iOS just like we have in Android and thats a big problem, I resolved it through manual anchors like this.
create a function with where in you calculate the height of the view using
mainView.contentSize.height
and then set anchors based on the total height to the enclosing view, call this function inside
override func viewWillLayoutSubviews()
And this would work, the viewWillLayoutSubviews() is a lifecycle method and whenever you override you have to do
super.viewWillLayoutSubviews()
This worked in my case, might work with yours too, if there is a better approach please do comment.
I want to show an alert controller of style action sheet to display the list of states in a country and that works fine.
But for some weird reason it shows action sheet below status bar partially which is not acceptable as it looks bad, how ever I can remove the status bar when displaying the action sheet which should work.
So I was just wondering is there any other way to make the action sheet stop to a particular offset from the top. I tried presenting the action sheet from the navigation controller but nothing changed.
Any comments appreciated.
Thanks,
Robin.
Try this:
var height:NSLayoutConstraint = NSLayoutConstraint(item: alertController.view, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 300)
alertController.view.addConstraint(height);
Set it height to 300. Look, will it do any changes?