I have UIPageViewController that contains simple UIViewControllers. The View of the VC contains an UIImageView (aspect fit) at the top and a UITextView at the bottom.
The LayoutConstraints for the ImageView are:
Fixed Width: Which has an Outlet to the VCs-Class
Fixed Height: Which has an Outlet to the VCs-Class
Center X is equal to the superviews centerX
Top is equal to Superviews MarinTop (+8)
The LayoutConstraints for the ImageView are:
Top is equal to ImageView bottom
Bottom is equal to superviews MarginBottom (+8)
Width is equal superviews width (Multiplicator is 0.8)
This works as expected.
But when the VC is loaded and has the image to display, I want to change the size of the imageView. There is a minimum and a maximum size and if a image view is smaller or larger it needs to be resized. Otherwise the the imageview has to get the size of the image.
So I calculate the size for the actual image and set the constant for the two LayoutConstraints. The values are correct but the ImageView does not change.
I tried to set them in viewWillLayoutSubviews but no change.
What am I doing wrong?
Try update your views inside viewDidLayoutSubviews:
- (void) viewDidLayoutSubviews {
// setup your constraints here
}
Hope this helps.
Write your change constraint code in the below provided block
dispatch_async(dispatch_get_main_queue(), {
})
Try changing the vertical spacing between the ImageView and the textfield to be flexible (>=0). If that doesn't solve the issue, add:
[view setNeedsLayout];
[view layoutIfNeeded];
After you adjust the size of the imageview to size of the new image.
Related
I have created a UIView that consists of 3 UILabels and 1 UIImageView as below -
The UILabels have lines set to 0 so that the height of the UILabels change dynamically
I have added constraints such that the height of the image depends on the height of the UILabels as shown below -
I have set width of the UIImageView to a constant of 100.
I would like to set a constraint on UIImageView such that the height of the UIImageView is equal to the height of the whole view.
I tried adding a "Equal Heights" constraint on the UIImageView and the whole view. I observed that the height of the whole view depends on the height of the UIImageView and not that the height of the UIImageView depends on the whole view as I want it to be.
Can anyone point out how I can add a constraint to the UIImageView such that its height is equal to its superview but the height of the superview is not dependent on the UIImageView?
Edit -
The below image shows the problem that I am facing. When an image is set to the UIImageView, the height of the view changes.
I want the height of the UIImageView to be equal to the height of the view, but I do not want the height of the view to be dependent on height of the UIImageView
Looks like you need to reduce the vertical content compression resistance on the image view.
Set it to something very low like 100 and try again.
I believe you haven't add the height constraint to the superview. Setup height constraint for the superview and then add a "Equal Heights" constraint on the UIImageView and the whole view.
In fact default compression resistance of your UIImageView is 750, while content hugging of root UIView is 250. This means AutoLayout engine layouts everything correctly. You can change vertical compression resistance to value lower then 250 (UILayoutPriority.defaultLow - 1) to achieve desired layout.
I have a screen layout where there are two resizable labels , which will contain multiline text. These labels are placed inside their parent views which intern are added to main contentView, main contentView is then added to scrollView ( thats what most of the solutions suggests). For both the labels (below About and Time and location labels in first image attached) I have set height constraints as "greater than or equal to" and setting the numberOfLines to 0 as well as calling SizetoFit, but actual output is not as expected (see second image attached). There are no constraints warnings. All constraints are provided for all the elements.
The code in viewDidLoad is as follows for one of the label.
self.lblAbout.text = #"this is a long two three lines about string which will have two lines this is a long two three lines about string which will have two lines";
self.lblAbout.numberOfLines = 0;
[self.lblAbout sizeToFit];
[self.lblAbout setPreferredMaxLayoutWidth:244.0];
Also
-(void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
scrollView.contentSize = contentView.frame.size;
}
Not if any additional constraints are needed, I have added all leading , trailing , top , bottom constrains along with height wherever needed, plus the spacing between all the views is in place.
What i want is the labels should get adjusted to number of lines and the contentView (parent view) should scroll inside ScrollView as the total height will be larger than the screen available.
*** problem I think is the outer view of the labels aren't getting resized as per the label because of which all the views below it aren't getting repositioned ****
Please try this Solution,
1. add Height Constraint to superView of your Label.
2. add IBOutlet of that Constraint
3. add this Method to find out Height of your Text
you need to give width of super view of your Label so width will be same as your super view
4. Now get Height form returned CGRect and assign it to your Constraints's constant. it should be like
heightConstraint.constant = youObject.size.height;
please Make sure you have added other Constraints accordingly this. if not than you need to also increase Height of other superviews accordingly.
(CGRect)sizeOfDetailLabelFromString:(NSString*)string maxWidth:(CGFloat)maxWidth{
NSDictionary *attributes = #{NSFontAttributeName:FONT_LIGHT};
CGRect rect = [string boundingRectWithSize:CGSizeMake(maxWidth, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:attributes context:nil];
return rect;
}
Here is what worked finally.
Added ScrollView in main View
Added View as a contentView ( be sure to rename it in designer to something than just view )
pinned scrollview to main view using leading trailing top and bottom space constraints.
Pinned contentView to scrollview same as above
Added all the components with their respective constraints
Set the height of UILabel which i want to resize using "Greater than or equal to constraint (this is necessary) and set number of lines to 0 in code
The parent view of label shouldn't have any fixed height but enough constraints to calculate it at runtime.
Make sure ScrollView has no ambiguity in calculating contentSize.
imp - Add constraints to width of Main view , scrollview , contentView ( that was in my case , you may not need equal width constraint between contentView and scrollview , but between contentView and main view its necessary)
Now scrollview scrolls exactly the way it's needed.
To my belief most of the above things i already did but somehow it wasn't working ,deleted everything and did all the things again few times and it worked.
I have a view named myView which is always half the screen and sit at the top of screen.
Inside this view I added an UIImageView with 120x120 size which sits in center of the myView (horizontally and vertically). Inside the IB, to satisfy the constraints(X & Y) I always need to set a fixed width and height for my image, after I set center horizontally and center vertically.
But with a fixed height and width, the image doesn't resize when changing the screen size. I want my image to resize when running on iPhone5 or iPhone 4s, because myView will resize.
I need something like the image should depend on the myView size.
How to actually achieve this ?
set imageView.clipToBounds = yes, and also set imageView.contentMode = UIViewContentModeScaleAspectFit;
Update
You are talking about imageView not the image, in that case it will not resize due to constant width and height, do one thing, create IBoutLet of constraint and change there values when required, or you can also set Aspect ratio with superView
If you set the image with fixed width and height it will not change respectively.
You can either set it to be relative to myView or you can instead set leading and trailing size from all for edges and delete the center constrains.
Your constraints should look like this:
For Swift 4: Updating answer of #Adnan Aftab
imageView.clipsToBounds = true
imageView.contentMode = .scaleAspectFit
I have a ViewController. In it I put ScrollView with the View(contentView). Later I drag from contentView to View and set Equal Height. Now it scrolls, but not fully.
As you see there are it has continue below the textView, but it
doesn't scrolls. How can I fix it?
UIScrollView is able to automatically calculate it's content height and width, but you need to help it with this.
To do so you need to:
Bound contentView (in your case) to all sides of superview (which is Scroll View).
Let contentView to calculate it's sizes. Here is a small mistake in your approach. You've set height of the contentView equal to View's height. So basically Scroll View's contentSize.height is the same as View's height. Which is not really what you want with dynamic content.
Usually you want to set width of the contentView equal to View's width and do not set contentView's height. Instead you want to bind subviews of contentView to their superview in such a way that their superview (contentView) will calculate it's height automatically.
In your case I would bind:
pizza.jpg to left-top-right of superview (height of pizza.jpg will be set from intrinsic image size);
SAMPLE TITLE label - left-right to superview; top to pizza.jpg image;
Text View - left-bottom-right to superview; top to SAMPLE TITLE label; set a fixed height.
In this case contentView will define needed height by itself. Scroll View will set it's contentSize accordingly.
And your screen will be able to scroll vertically (it should be) ;)
You need to set the contentsize of the scrollview. Use the below code to do that:
func viewDidLayoutSubviews()
{
super.viewDidLayoutSubviews()
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width, self.contentView.frame.size.height);
}
To use Autolayout with UIScrollView is tricky.
In your code you have to update height constraint for your contentView by calculating height of subviews of contentView and that will automatically update the contentSize for your ScrollView and you can scroll through all subviews.
For more info to use Autolayout+UIScrollView your can read this.
According to this link (thanks to this Matt's answer first), UIScrollView acts differently with AutoLayout than the other views.
Subviews of a scrollView set their constraints from the contentView of the scrollView and not the scrollview directly. This allows the content to scroll.
So :
Add a UIView to your scrollView, this will represent the contentView of your scrollView. Add constraints to top, bottom, trailing, leading from the view to its superView
Interface Builder complains. Here you see the different between a basic view and a scrollView. The reason is a contentView has to be fill to know its size. So add a equal width from the contentView to the scrollView
The contentView knows now its width but not its height. So add your labels and your UIImage as subviews of the contentView. Add constraints from bottom to the top. Don't miss to add a height constraint to the UIImageView.
It should look like this :
Hope this helps
Read this (from Matt once again) for further informations
I'm trying to make layout inside scrollview using this one tutorial link
And get the following result link
It will be appreciated for any advices or tutorial links. It needs only vertical scrolling
I am sure there must be other ways to do this but a quick fix is :
1.) Create a width constraint on ContentView in Storyborad.
2.) IBOutlet that widthContraint and set its value to the view frame width in viewDidLoad.
Suppose the name of the constraint outlet is contentViewWidthContraint.
contentViewWidthContraint.constant = self.view.bounds.size.width;
Another alternative to do so from Storyboard, is to fix the Contentview width to the view's width from the storyboard or to the Scrollview, if Scrollview already has a Equal width contraint with superview . Add the "Equal Width" contraint from Contentview to either self.view or to Scrollview (if scrollview, already has the width contraint)
Have you set up the "ContentView" width to match with the scroll view width? I had the same problem and I fixed with "Equal Widths".
"Equal Widths" will tell to your "ContentView" to use the same width of the "Scroll View", which should be fitting the screen if you have set up the constrain properly.
You can do this easily on the storyboard.
Drag and drop, with right click (important!!!), from "ContentView" to "ScrollView"
Release the click, you will be prompted with a menu, select "Equal Widths".
This should fix your problem using the scrollview with AutoLayout from Storyboard editor.
You can find a full tutorial how to use ScrollView with Autolayout and Storyboard here.
I hope this is useful for you :)
In the Storyboard set the width of the elements contained in your UIScrollView equal to the width of this UIScrollView (by selecting all elements and the UIScrollView holding in the panel on the left of your Storyboard and then setting the 'Equal Widths' constraint under 'Pin' on the bottom of your Storyboard). Just pinning the right sides of the elements to that of the UIScrollView won't work as it will adjust the size of its "display view" to the width of the largest element and if this is smaller than the width of the UIScrollView all elements will just appear aligned to its left side.
There is also another possibility that offers a very good result.
You can mark a checkbox:
O programmatically:
scrollView.alwaysBounceVertical = true
Try to set it's width to 0 & height equal to content size like this:
self.scrollView.contentSize = CGSizeMake(0, self.scrollView.contentSize.height);
This will work as you want. Try it & tell if still facing any issue.
For disabling the horizontal scroll, you can set the content size in the -(void)scrollViewDidScroll method.
[self.scrollView setContentOffset: CGPointMake(0, self.scrollView.contentOffset.y)];
self.scrollView.directionalLockEnabled = YES;
This is because scroll view have no idea where your content should end.
But when at least one item inside your scroll view has its "trailing space" constraint attached to a view outside the scroll view (usually a view the scroll view is sitting in or some other view of a higher level, which "knows" its width) - the scroll view will automatically get an idea about your wanted width and won't scroll horizontally (unless that trailing constraint implies having your content outside the screen).
Better if all items inside scroll view have their "trailing space" constraints connected either to each other or to a view outside the scroll view. But not the scroll view itself.
No additional code or extra constraints needed for this to work.
Too set UIScrollView constraints as like below code so it will occupied whole screen.Not exceed the screen size.
Leading Space = 0 from mainView
Top Space = 0 from mainView
Bottom Space = 0 from mainView
Trailing Space = 0 from mainView
You need to set the width of UIScrollView equal to or less than the width of your Parent View. Two ways to do it:
1) You can do this in Storyboard via layout constraints
2) You can do this programatically:
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width, self.scrollView.contentSize.height);