I have 3 UIViews and added 3 labels to each view as subview. When I resize the views, so that their height becomes zero, still all 3 labels are visible.
And one more point that, initially the labels are at the center of UIViews but when I increase views height, they(labels) do not remain to the center of views.
Does any body know what is this and solution to this?
UIView property clipsToBounds is set to NO by default. Set the property to YES to avoid showing subviews outside of the current bounds.
you can use autoresizing to manage that if you don't use autolayout.
Related
Is it possible to have 2 different UIViews connected to the bottom of the ContentView of the UIScrollView and toggle them at the click of a button?
The hierarchy of Views I have right now -
UIScrollView
ContentView
UIView1
UIView2
What I exactly wish to achieve is to have both UIView1 and UIView2 connected to the bottom of the ContentView and switch between the two cases programatically.
I tried making one of the 2 constraints optional and then switching priorities according to my cases but it says I can't change the priories of already loaded views to required from optional (or vice versa).
You can't change the priories of already loaded views to required from optional. but you can definitely increase the priority in the same range. example- priority1 = 750 ,priority2 = 760
The problem I am forcing is:
I have 1 big scrollView and I have to add to it 5 subviews programmatically
when I don't know what heights the sub views will have :(
Is there some API to do so ?
or I have to count the subviews heights manually and add them with CGRectMake
based by calculated sizes?
What I would do is use Auto Layout. If you add your subviews to the scroll view using internal constraints, then these constraints can determine not only the distance of the subviews from one another but also the distance from the imaginary content view that surrounds them. The scroll view then uses the size of the content view as its contentSize, and the whole thing becomes scrollable. And this works despite the fact that you don't know the heights of any of the views, which is exactly what you're after.
I'm facing very weird issue, I have UIView grandWrapper namely in which I'm adding many subviews now when i animate the height of my grandWrapper to zero, ideally height of grandWrapper should be zero and all the inner views should disappear since they were existing inside that grandWrapper View but It animates the height to zero and all the subviews are still there. Can anyone help?
P.s. Im creating subviews programmatically. Thanks in advance
Make subview's autoresizingMask property contains UIViewAutoresizingFlexibleHeight if you want the subviews resize its height according to their parent's height.
Or you can set the view's clipsToBounds property to YES.
Little bit confused from your question
1.If you want to remove your grandWrapper sub views then call below function
-(void)clearReportContent
{
if(grandWrapper!=nil)
[[grandWrapper subviews] makeObjectsPerformSelector: #selector(removeFromSuperview)];
}
2.If sub views are appearing on screen when you do the grandWrapper height to zero,
then set grandWrapper.cliptoBounds=YES; at start where you add the sub view on grandWrapper.
I have a tableview with cells containing text views as well as imageviews. My project is currently using AutoLayout. My goal is to get the imageview to display in fullscreen when it is tapped. One option is to use a modal view controller, but I want to have this work sort of like the way tapping on images in the facebook app works, the app centers the image and fades the background.
Since I'm using autolayout, I cannot simply set the frame of the imageview to fill the screen. Instead, I need to use autolayout constraints. My image view has 5 constraints, a constraint setting a distance from the bottom of the cell, as well as the left an right sides, and one controlling the image height. The last is a vertical space constraint between the textview above the image view and the top of the image. While this would appear to conflict with the height and bottom constraints, for some reason interface builder forces me to have this. To avoid problems, I set this constraint's priority to be less than 1000 (the image should never overlap the textview anyways, since the tableview cell height is set so everything will fit perfectly).
To center the image, I set the distance from the left and right to be zero and remove the vertical space constraint. In order to center the image, I replace the bottom space constraint with a center y alignment constraint to the UIWindow as opposed to the tableviewcell. I want to have it be in the center of the screen, not the cell.
To get the main window I use this:
AppDelegate* myDelegate = (((AppDelegate*) [UIApplication sharedApplication].delegate));
//access main window using myDelegate.window
Then, to set the constraint:
//currently sets the distance from the bottom of the cell to 14
//changing it...
[cellselected removeConstraint:cellselected.imagebottomspace];
cellselected.imagebottomspace = [NSLayoutConstraint constraintWithItem:cellselected.viewimage attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:myDelegate.window attribute:NSLayoutAttributeCenterY multiplier:0 constant:0];
[cellselected addConstraint:cellselected.imagebottomspace];
However, this doesn't work. The changes in the width and height of the image view apply just fine. However, when readding the imagebottomspace constraint, I get an unsatisfiable layout--apparently the constraint conflicts with another constraint which sets the distance between the bottom and the image view to 14, the very constraint I just removed. So it seems that it isn't actually removing the constraint.
When I proceed and let the app break a constraint, the imageview moves, but to the wrong place. It isn't centering in the screen. It moves way up and off the screen.
Obviously what I'm doing isn't right. What am I doing wrong?
So I guess you want something like this:
First, you need to know that as of Xcode 4.6.3, the nib editor (“Interface Builder”) has a bug when setting up constraints in a table view cell. It should create the constraints between the subviews and the cell's content view, but instead it creates the constraints between the subviews and the cell itself. This tends to screw up layout at runtime. (This bug is fixed in Xcode 5 and later.)
The consequence of this is that you should either remove all of the constraints that were in the nib and recreate them in code, or just get rid of the nib and create the cell's entire view hierarchy in code.
Second, there's an easier way to do the image zooming. Here's the basic procedure when a cell is selected:
Convert the selected cell's image view bounds to a CGRect in the top-level view's coordinate system.
Create a new image view just for zooming and set its frame to that CGRect. Set its userInteractionEnabled to YES. Set its autoresizingMask to flexible width and height. Add a tap gesture recognizer.
Add the new image view as a subview of the top-level view.
Set the cell's image view's hidden property to YES.
In an animation block, set the new image view's frame to the top-level view's bounds.
Disable the table view's panGestureRecognizer.
When the new image view is tapped, reverse the procedure:
Convert the selected cell's image view bounds to a CGRect in the top-level view's coordinate system.
In an animation block, set the zoomed image view's frame to that CGRect.
In the animation completion block:
Remove the zoomed image view from its superview.
Set the cell's image view's hidden property to NO.
Enable the table view's panGestureRecognizer.
Since you're not moving the original image view, you don't have to mess with its constraints. Hidden views still participate in layout.
Since you're creating the new image view in code, it will have translatesAutoresizingMaskIntoConstraints set to YES by default. This means that you can just set its frame. Auto layout will automatically turn the frame into constraints.
You can find the full source code in this github repository.
I've just come across a similar issue. I think that the reason for these problems are that the views embedded in UIScrollViews exist in a different bounds system to those of the views outside it. This is effectively how scrolling works in the first place, think of it as just applying a variable offset to the views it contains. Autolayout doesn't know how to translate between these different coordinate systems so any constraints that bridge across aren't going to be applied the way you expect.
To quote from Erica Sadun's excellent book iOS Auto Layout Demystified (from the section 'Constraints, Hierarchies, and Bounds Systems'):
"Be aware of bounds systems. You should not relate a button on some
view, for example, with a text field inside a separate collection
view. If there's some sort of content view with its own bounds system
(such as collection views, scroll views, and table views), don’t hop
out of that to an entirely different bounds system in another view."
I have one UIView and inside that, N UILabels which are laid out relative to each other.
The containing UIView has a background color, I want to extend the UIView to be high enough to cover all labels inside it, so the background color is behind them all.
(I'm embedding them in a UIView so I can have the labels inset from the view edges.)
Is there away to make the UIView's height expand to fill its content? I can't figure it from the constraint options, it seems like its all relative to superviews.
Normally I'd just work out the frame sizes programatically in viewDidAppear but those are getting reset by the constraints system, AFAIK.
I think I actually worked it out though.
I had the labels height set manually from when I drag-dropped and resized it. Deleting the height constraint on the UILabel made it size to fit content, which causes its superview to resize too. At least I think that's the case, I'm new to constraints.
Will leave the question up since it will probably bite someone else too.