UITextField: adjustsFontSizeToFitWidth behaviour/ issue - ios

I have an issue with the usage of textField’s adjustsFontSizeToFitWidth. I have a textField with font size of 50 and a maximum width of 300 (This is a less than or equal to constraint). TextField is placed centre vertically and horizontally using auto layout. Now when I run the app, the text is being shrinked from the beginning itself. I know this may be because the system thinks the bounds of Texfield is not enough… but I gave the control to auto layout to figure that out and I assume it should work. Below is the snapshot… you can see the big placeholder and then suddenly the text shrinks… Any thoughts? Am I doing something wrong, I was trying to avoid manual calculation of width..
SourceCode Sample

Set leading/trailing space to text field like 15 pt from left safe area and 15 from Button so that it could automatically increase the font size. As now it shrinks the font to minimal 17 (which is set in storyboard) as the width is not enough.

Okay!! Finally I found a way, the idea was to check if the width is greater than the defined width limit... when the width is more I set adjustsFontSizeToFitWidth = true else set to false ... for some reason the solution didnt work when I clear the text... then I tried programatical approach and it started working .... dont know what was the difference... anyways I updated the source..... if there is a better solution let me know.
#IBAction func textChanged(_ txtField: UITextField) {
if txtField.frame.width >= (view.frame.width * widthMultiplier).rounded() {
txtField.adjustsFontSizeToFitWidth = true
} else {
txtField.adjustsFontSizeToFitWidth = false
}
}

Related

How to set UITextField width constraint to have room for a certain string

I have a UITextField that will display floating point values between 0 and 1.0 with 3 digits after the decimal point. So the widest text it will show is something like "0.000". I'd like to set the auto layout width constraint so that the text field always has just enough room to display this value.
The code below is close, but does not work.
let biggestString = "0.000"
let textAttrs = [NSAttributedStringKey.font: myField.font]
let size = (biggestString as NSString).size(withAttributes: textAttrs)
myField.widthAnchor.constraint(equalToConstant: size.width).isActive = true
It ends up displaying "1.0..." I'm guessing this is because a UITextField has some kind of padding around the text, so so I need to set the width to be the string width + the padding. But, I don't see a property from which I can read this padding amount. Is there a way to get it?
Try searching for the 'intrinsicContentSize'. According to the documentation this is what has to be set to indicate to the auto-layout how big the content is.
There was also a more elaborate discussion on how this can actually if the layout settings do not allow the resizing to work, see other question here:
How to increase width of textfield according to typed text?

Prevent UITextView from offsetting its text container

I am tying to modify the height of a UITextView dynamically (up to a max height) while the user enters text. I am experiencing a very strange behavior when there are an even number of lines in the text view.
I am using autolayout and the text view has a height constraint. I respond to calls to the text view's delegate (textViewDidChange(_:)), where I calculate and adjust the height constraint based on the contentSize.
Here is the code:
func textViewDidChange(_ textView: UITextView) {
let newHeight = textView.contentSize.height
let newConstraintConst = max(MinTextViewHeight, min(MaxTextViewHeight, newHeight))
self.textViewHeightConstraint.constant = newConstraintConst
}
This works well, it resizes the frame up to MaxTextViewHeight and then the text view can scroll. However, when there are an even number of lines in the text view, the text view adds a kind of offset to the bottom of its NSTextContainer, causing the top line to be cut off:
However, when there are odd lines the NSTextContainer is no longer offset:
At first I thought it was somehow being controlled by the text view's textContainerInset but that is only used to pad the space inside the NSTextContainer, as setting it to .zero removes the space inside but does not affect the offset (and incidentally makes it even worse, as the top line almost completely disappears):
I have looked through the UITextView class reference and I don't see any property that would let me manipulate or even get the value of this offset.
As a workaround I am increasing the text container's top inset and removing the bottom inset:
textView.textContainerInset = UIEdgeInsetsMake(10, 0, 0, 0)
This works so far, but I arrived at a value of 10 by trial-and-error, and so far I've only tested it on a single device.
I am not interested in more hacky workarounds that require fragile, fixed values; I am trying to understand how this offset is being set and a proper way to fix it. I'm hoping that someone can provide some insight, thanks!
Just a speculation, but I think the problem is that the text view assumes that the height of itself does not change while calling textViewDidChange, so it scrolls when it thinks it has to, regardless of you changing its frame.
Not sure if you think my solution is too hacky, but this will stop it from scrolling when you don't want it. I simply pin the content offset to the top as long as the wanted content size is smaller than your max size.
Just add this:
func scrollViewDidScroll(scrollView: UIScrollView) {
if textView.contentSize.height <= MaxTextViewHeight && textView.contentOffset.y > 0.0 {
textView.contentOffset.y = 0.0;
}
}

How to prevent UILabel to fill the entire screen?

I am trying to display a UILabel that may take up multiple lines but I'm having problem with how the height is resized.
Here is what it looks when I have text over a single line, displaying correctly:
When the text spans multiple lines however this happens:
Here's the interface builder settings I'm using:
Ideally I'd like the text view to remain at athe top of the screen and just take up as much space as it needs to diaplay the text but I really can't tell where I am going wrong.
The text view is a bit tricky to handle with automatic layout. If possible use an UILabel. If not then there are several issues with the text view and the most manageable solution is to add the height constraint which is then manipulated in the code.
The height of the text view content can be determined as:
let height = textView.sizeThatFits(textView.frame.size).height
It is also possible to use
let height = textView.contentSize.height
But the results are sometimes incorrect.
You do need to then set the delegate for the text view so that on change you will refresh the size of the text view.
Well you did give it permission to do so based on your constraints. Any height > 0 as long as it's 20 from the top margin. Since you don't have any other views to base your height off of you can hook up an outlet to your label and use this:
#IBOutlet weak var label: UILabel!
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
label.sizeToFit()
}
Uncheck the "Preferred Width" explicit checkbox(In Size Inspector)
Remove the height constraint on you UILabel.
It will definitely work.

Animated width label with swift

I want to change the width of my label since my swift code.
If possible, do it in a annimation prograssif for a change. Is it possible ?
When I do:
self.lblChoice1.frame.size.width += 50
My exchange label width not ... Why?
Thank you in advance.
EDIT :
The first response is not working.
print(self.lblChoice1.frame.size.width)
self.lblChoice1.frame.size.width += 150
self.lblChoice1.contentMode = UIViewContentMode.Redraw
self.lblChoice1.setNeedsDisplay()
print(self.lblChoice1.frame.size.width)
This code displays me well in my console:
150.0
300.0
But my label size does not change the display ...
You are changing the frame, but you aren't telling the view that it needs to redraw itself. After changing the frame you should then call
self.lblchoice1.setNeedsDisplay()
Although you may need to change the label's content mode to UIViewContentModeRedraw to make sure it redraws.
Although it would be better to use UIView block animation methods to do this.
I dont think you can edit the UILabel's frame directly. You should change entire frame instead.
var lblChoice1Frame = self.lblChoice1.frame
lblChoice1Frame.size.width += 150
UIView.animateWithDuration(0.3) { () -> Void in
self.lblChoice1.frame = lblChoice1Frame
}

The height of textview with attributed text is wrong sometimes in iOS

I'm forcing the height constraint of my textview with the following code
func setHeightConstraint(textView: UITextView) {
textView.sizeToFit()
textView.layoutIfNeeded()
var newFrame:CGRect=textView.frame
newFrame.size.height=textView.contentSize.height
textView.frame=newFrame
println(textView.contentSize.height)
textViewHeightConstraints.constant=textView.contentSize.height
}
My text view contains attributedText with links, bold, italic and so on..
It works well sometimes, but does not on other times.
I figured by printing textView.contentSize.height, that textView.contentSize.height is sometimes much smaller than it should be.
I used that code snippet with normal text with no issue, so I guess it is a problem about attributedText.
I tried googling and tried this and that code with no luck.
How should I measure the correct height of the textView when it contains attributedText??
Any help will be appreciated.
Thanks in advance!
(I can read Object-C code also though I prefer swift, so Object-C answer is appreciated as well!!)
It sounds like you are trying to make a text view whose height can be adjusted to fit its contents. This is how I do it:
func adjustHeight() {
let sz = self.tv.sizeThatFits(CGSizeMake(self.tv.bounds.width, 10000))
self.heightConstraint.constant = ceil(sz.height)
}
In that code, self.tv is the text view and self.heightConstraint is the internal constraint that sets its height.
There are major problems with your code, by the way. In particular: If you are using constraints you must not use frame! The constraints position and size the object; that is what they are for.

Resources