I read that you should not normally use setFrame when you are using autolayout.
However, if I have a constraint from a UIButton to a UITextView, lets say the UITextView's height changes and in the IB I set the UIButton's constraint to be 10 vertical unit spacings apart from the UITextView. When I change the UITextView's height by using setFrame, is there anyway to get the UIButton to automatically recalculate it's y position based on the constraint?
Thanks!
You really shouldn't modify the view's frame when using autolayout. You need to modifiy the constraint, wether by resetting it programmatically or by adding an IBOutlet that references the constraint and modify its constant value.
You might want to take a look at this article
Related
Possible a duplicate, but I tried could not make it work so came here.
I (new to autolayout) have two UILabel place one below each other with fixed height space.Both can increase with as per text with in it.
When First UILabel hides bottom should move to First place. How to do it using constraints in view only? I know how to do by creating IBOutlet connection of constraints for second UILabel.
EDIT:
Given question is about more about content hugging related, where as my question is add constrains to move to first UILabel position when first hides.
The only way to achieve what you want with AutoLayout is to set constant of all related constraints to zero. And remember NEVER try to set frame or bounds of your view if you are using AutoLayout(unless you override layoutSubviews and do the stuff in that method, which you rarely need to).
You can check out this tiny project: https://github.com/neevek/UIView-Visibility, I bet that is what you want :-)
I'm trying to adjust the size of a button to (it's intrinsic size + a little bit more) in order to draw a custom background. However, every time I access self.titleLabel within the button, the size and position resnaps to that of the storyboard. I don't have to do anything with the label to reproduce this, just retrieve it from the button.
I've put logging code all over my button and view controller in order to find where this is happening. It's not coming from a relaying-out of subviews or any other notification I see to get within the view controller. The line before accessing titleLabel, the position and size are correct. The line after, it has snapped back to the storyboard position. Commenting out the access prevents the size/position snapping. Can someone tell me where or why this is happening?
I have no constraints set (that I can tell), but am I fighting against auto-layout here? Should I be doing this a different way like composing controls or something?
Something similar (or the same?) has been asked before at UIButton modifying titlelabel seems to change its frame and UIButton titleLabel resizes on press?, but both were left unanswered or explained away with just "maybe a bug."
If the project has auto-layout enabled, then YES, you're fighting auto-layout. You have two choices, either subclass UIButton so that you can override the intrinsic size calculation, or modify the constraints so that the intrinsic size is not used in any constraint. If you do the latter, then you probably want to create an IBOutlet to the constraint for the width, so that you can adjust the constant property as needed.
This isn't a bug, it's a consequence of auto layout. When using auto layout, you shouldn't set any frames. Instead, you should change the size or position by modifying the constraints. What's happening, is that whenever the view needs to be redrawn, the frame reverts to the frame that's defined by the constraints.
Using Storyboards I add a UIView with height of 5px.
At run time the height of that view is increased (could be up to 25px).
When the orientation changes, the height of the view is reverted back to the original 5px.
How can I prevent this? I want the height to remain at whatever it was prior to the orientation change.
Sure I could detect orientation change and then change it back but that looks sloppy because it shrinks then increases right away.
Edit: This may or may not be an autolayout issue. Or might just be the default behavior of storyboards.
Add a constraint fixing the height, you may also need to remove a constraint. If you show the code or explain how you're setting the constants in the first place can give a more detailed answer.
Other answer is to remove the constraint that stretching the size of your view, may be that you have conflicting constraints.
One more answer could be you need to adjust the priority of an other constraint perhaps one for spacing between views. Again more detail = better answer.
Overriding -layoutSubviews is the incorrect approach. If you're using autolayout you should adjust a view's height by modifying its constraints programmatically.
Make a property for your view's height constraint:
#property (strong, nonatomic) IBOutlet NSLayoutConstraint *heightConstraint;
I put IBOutlet there since you said you're making the constraints in a storyboard. Just drag the height constraint to that property to connect it. (You could also create the constraint programmatically, in which case you wouldn't use IBOutlet.)
Then, whenever you want to change the height:
self.heightConstraint.constant = 25;
The solution to the problem is to sublcass UIView and override -(void)layoutSubviews
In -(void)layoutSubviews is where I set my desired height
I'm fairly new to iOS development and am having a hard time sizing a UITextView to it's content. I've found several examples of calculating a strings render size and/or updating the frame size of a textview, however I can't seem to get those to work.
When I add a UITextView to my view it adds a Height constraint which I think is locking it to a specific height. How can I work around it, update the constraint via code, and/or get my UITextView to resize vertically to show my content?
You can create an outlet to the vertical size constraint, and then adjust the .constant property of the constraint to amend the height of your text view.
A UITextView inherits from UIScrollView. As part of it's logic, it changes the height of its contentSize property to allow the user to scroll vertically to any portion of the TextView's content.
I would recommend using the ContentSize property of your UITextView to figure out how "tall" your content really is. You can then set the frame of your UITextView accordingly.
OR: You could figure out the size of your text using the right method from the NSString+UIKitAdditions category.
If you don't want autolayout then disable it in the xib file.
If you want to change the contraint and it's value this tutorial will help you to deal with autolayout.
I'm creating a xib using autolayout (NSLayoutConsraint). Is there a way to use sizeToFit or something similar to make a UILabel fit its contents?
I've tried setting a constraint of "greater than or equal to x" and tried setting the height to be below this. However, it keeps overwriting the height property. sitToFit doesn't seem to work when you have NSLayoutConstraints.
How can I get the label to size appropriately?
Make an IBOutlet for your width and height constraints, and use sizeToFit to change their constant property, and call needsUpdateConstraints
Using a "greater than constraint" for the height of the UILabel and
calling sizeToFit within viewDidLayoutSubviews did the trick for me
I did not need to call needsUpdateConstraints.
You also need to set the number of lines to 0 to allow an unlimited amount of lines or > 1 if you want a limit.
Also the property preferredMaxLayoutWidth needs to be set, which is automatically set to the views width by the interface builder.
You should try to lower your height constraint priority.