is there a way in which a UITableView can always take a fixed height and can scale the static cells i'm using to the remaining height? I'm trying to achieve that my tableview layout is always visible on different devices.
I think I understand what you're getting at with having the table view showing on all devices. Instead of setting a specific size I'd recommend using auto layout instead! You can read more here.
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I have a stack view that contains three UICollectionViews, set up to give each of them equal vertical space. That stack view is set to be the height of half of the display, so that it uses more space on larger devices. This has been set up in Interface Builder.
So, I need to set the cell size of the UICollectionView at runtime, since until we are running, I don't know what the actual size of the cells will be. I want them to be square, so I just want to take into account the height of the UICollectionView, subtract out the top and bottom section insets, and set the itemSize to the resulting size.
I attempt to do this in viewDidLayoutSubviews, since by then I figure that the initial heights of the collection views have been set. However, they appear to be set to 1000x1000 (even though they are a much more reasonable size in the storyboard), and so I compute a cell size based on a collection view height of 1000. This is too large, but I figure that I'll get called again and get another chance to recompute it. And I do, but not before UICollectionView complains loudly that the itemSize is incorrect (ie. too large to fit in the collectionView, which now has the "correct" size.)
What is the best way to get the behavior I'm looking for without the warnings from UICollectionView? Setting the collection view item size at runtime based on the eventual size of the UICollectionView is something I've struggled with in the past, and there never seems to be the "right" time to set the itemSize. I don't want to dynamically return it, if only because it's not something that changes during the life of the program. There just seems to be some inconsistencies that occur when laying out the views initially.
It seems odd to me that the collection view comes in with an initial size of 1000.0 by 1000.0, but I'm not sure how or why to fix that - perhaps it has something to do with being embedded in a stack view?
Edited to add: It is almost certainly the UIStackView that is causing the layout issues. I created a dummy project to test the size of a UICollectionView when it is the top level view vs embedded in a UIStackView. If it is not embedded, when viewDidLayoutSubviews is called, it has been properly sized to fit the bounds of its superview. However, if it is inside of a UIStackView, it stays at the default size of 1000x1000.
For now, I am working around this problem by adding the following code in viewDidLayoutSubviews:
if collectionView.bounds.size.width > view.bounds.size.width {
view.layoutIfNeeded()
}
Where collectionView is inside a UIStackView and view is the main view of the UIViewController. This allows all subsequent calculations based on the size of the view to be correct, and hopefully will not get called if the UIStackView behavior ever gets fixed.
Similar discussions here and here. Interesting point that in XCode8, the new default is to not save sizes of views in the XIB file, but instead bring everything in with an initial size of 1000x1000, to be resolved during the first layout pass. Except for UIStackViews, I guess.
Are you having sizeForItemAtIndexPath() return itemSize? I have found that implementing that function is the only reliable way to size a UICollectionViewCell dynamically at runtime.
I'm populating an UILabel with JSON data and I want it to adjust its height to the content it loads. Also the rest of the labels in the view should move. How can I do this using Swift?
Use autolayout.
You can give priority to the label you load from the json and shrink other labels.
This tutorial is a good place to start with auto layout - http://www.raywenderlich.com/115440/auto-layout-tutorial-in-ios-9-part-1-getting-started-2.
Visit http://nscookbook.com/2015/06/ios-programming-recipe-36-a-fixed-width-dynamic-height-scrollview-in-autolayout/
You can do that either in the storyboard or in the code
I would consider putting the labels in a UIStackView if your app requires iOS 9+. If for some reason the labels aren't resizing properly when you change the text, you can force it by calling [label sizeToFit];.
Is there a way to have each label equal distances apart depending on how many lines are displaying per table cell. I can see all the data if I use both hands to tug the info up the screen but that isnt user friendly.
It sounds like you have UILabels in UITableViewCells? You may need to adjust the height of the cells via UITableViewDelegate's tableView:heightForRowAtIndexPath: message. In there, you probably want to calculate your height using boundingRectForSize:options:attributes:context: from NSString (iOS 7 and later). Make sure the numberOfLines property in your UILabel is 0 to adjust for the expanding height, and set the appropriate constraints.
I have a UIScrollView with several UITableViews embedded in it. I want to allow each table to expand its height as much as is needed to display all of its cells. The scroll view's frame takes up the whole screen, so its contentSize.height need to expand to fit the biggest table (which I think is the default behavior, but I mention it just in case I'm incorrect). Can this all be done on my storyboard? Or if I will need to add code to do it, I found this tutorial, but it's for iOS 6 - has any of the code for this constraint stuff changed for iOS 7?
If you know in advance how much room each table takes up you can do it purely in your storyboard, but because each UITableView is also a scrollview the default behavior of a UITableView is to fill the assigned size with content and scroll if there is overflow.
If you do not know the height of the tables at design time, you will need to set them at run time. See Autolayout a UIScrollView to fit content including subviews and grouped tables for an example, the short answer is to add a height constraint to your table, drag it into your controller as an outlet, and then set the height when you know it.
It can be done both ways.Manually moving UI elements through code(mentioning locations) and overriding it in did rotate or through mentioning constraints in auto layout.
This link http://www.doubleencore.com/2013/09/auto-layout-updates-in-ios-7/ provides details of ios7 auto layout .
I have built a very simple sample of an app (Source code on github) using a UICollectionView.
Everything is working fine, as long as the app is in portrait mode. When it is changed to landscape mode however, the content cell is not resized appropriately, and thus, nothing is displayed.
I thought that all the necessary AutoLayout constraints are in place. I am aware that I can implement collectionView:layout:sizeForItemAtIndexPath:, but my goal is to use AutoLayout as much as possible (simply to understand AutoLayout better).
What am I missing here?
You can use autolayout to set the position and size of the collection view. And you can use autolayout to set the position and size of the subviews inside each cell. But you cannot use autolayout to control the position and size of the cells. You must use the collection view's layout object to set the position and size of each collection view cell. If you want the cells to change size when the interface orientation changes, you must update your layout object to report the new size and invalidate the layout.