Using the Storyboard editor with auto-layout and constraints, I have created a hierarchy with a UIViewController (1) inside of which there is a Container(2) into which in turn a UIViewcontroller(3) is embedded.
Setting the background color of the embedded UIViewController(3) to a different color than (1) shows me that the restraints are being enforced: Visually, it appears to have the size I expect both in the storyboard-editor, in the emulator and on my device.
But I fail to get the size of UIViewController(3) from code, I have tried accessing the UIViewControllers(3) views frame and bounds, both with incorrect results, they seem to return the same size as the size of the host UIViewController(1), which is clearly wrong since once is indeed embedded in the other.
I have tried also accessing the self.parentViewController.view frame and bounds, but these both return 0.0.
In the embedded UIViewController (3):
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"Size: %f x %f", self.view.frame.size.width, self.view.frame.size.height);
NSLog(#"Origin: %f x %f", self.view.frame.origin.x, self.view.frame.origin.y);
}
I would expect the output of this to be something which resembles, atleast in aspect ratio, the actual visible size of the UIViewController (3), but it is in fact equal to what I get if I put the same code from UIViewController (1), which is clearly not true since they are not of same size.
I usually make an outlet for the view, which makes it much easier to get the parameters e.g. in your interface make an IBOutlet and connect to your view
IBOutlet UIView *outletYourView
and wherever you need the information call
outletYourView.frame.size.width;
outletYourView.frame.size.height;
etc.
Related
I'm loading a view from a storyboard programatically, but there's an issue with my subview heights (I'm using Autoresize Subviews etc).
When the view loads, the main UIView appears to be the correct size, but the subviews that depend on the constraints to dynamically calculate their final height don't seem to be resizing from the sizes they were set at in interface builder.
Loading the view like so:
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
ApplicationRecordingViewController* recordingController = (ApplicationRecordingViewController*)[storyboard instantiateViewControllerWithIdentifier:#"recordView2"];
[self presentViewController:recordingController animated:NO completion:nil];
Orange area's height is from top of main view to top of grey area. Grey area is fixed height
The strange thing is, if I set the simulated size in interface builder as the correct view for my phone, the sizes work out. I guess the initial heights for subviews are 'baked' into the view, but then (usually) resized when the view actually loads?
Note: The orange area should be completely filled by the camera view I'm loading into it.
Incorrect height
Correct height if I change simulated layout
Would love to know what I'm doing wrong!
Edit 1: Constraints
Camera is the orange bit. The Camera bottom constraint is currently set as the bottom of the view + enough room for the gray bar. Have also tried setting the bottom to match the top of the gray bar!
Link to Storyboard with Scene
I know you're all better than me, but I experienced the same in my last project. My Camera View inside a UIView is not in full screen or resizing and fitting the whole UIView, and I also posted it on my daily blog.
Implement viewDidLayoutSubviews -- Inside that method, layout again your video preview layer.Do not alloc init anything inside that method, just re-layout your views. After that, your video preview will fill the height and width of its parent, or whatever you've been targetting.
The issue also has something to do with the hierarchy of the constraints and views.
You already got the answer.
'if I set the simulated size in interface builder as the correct view for my phone, the sizes work out.'
You may call some functions to get height in viewDidLoad or viewWillAppear.
Change Code like this
- (void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self.view setNeedsLayout];
[self.view layoutIfNeeded];
CGFloat height = [self getHeight];
}
or
- (void) viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
CGFloat height = [self getHeight];
}
As i can see in your storyboard constrain you have set bottom space to bottom layout guide 150 . i think this is the issue . if you give fixed height to bottom view then no need to set constant as from bottom layout guide --> 150 .
Your old constrain :- >
Just set bottom space of orangeview from greenview = 0.
Check new constrain ,
Here is your storyboard link ,
Storyboard Download link
Here is your output,
After investigating the layout a little more, I found the camera view (orange) seemed to be the correct size, but the live camera preview wasn't.
Solution was to move the camera library (SCRecorder)'s init method into viewDidAppear (was in viewDidLoad before).
My thinking is iOS doesn't autolayout the camera preview view in the same way as normal UIViews, etc.
#interface ApplicationRecordingViewController () {
SCRecorder *_recorder;
}
#end
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
_recorder.previewView = _previewView;
}
Perhaps you can try to get rid of these two hook.
I have two questions related to UITableViews.
1) The first one is, what is the gap at the top of the UITableView? My app always starts with the top cell not flush with the top of the tableview (as shown in the second image), it starts about one cell lower, i.e. where that gap is in the interface builder. I can't find where that is coming from, or why.
2) I can't seem to resize the uitableview programmatically, I'm trying to reduce the height after a popup appears. I've shown an example of it not working in the second picture.
Here is (an example of) what I am trying at the moment:
- (void)viewDidLoad
{
[super viewDidLoad];
self.table_view.delegate = self;
CGRect tableBounds = self.table_view.bounds;
tableBounds.size.height -= 100;
self.table_view.bounds = tableBounds;
CGRect tableFrame = self.table_view.frame;
tableBounds.size.height -= 100;
self.table_view.frame = tableFrame;
}
Thanks!
UITableView Selected:
Simulation:
In your xib (or storyboard) put your UITableView at position (0,0). ( the same position as the navigation bar).
The first image shows that your table view has problems even in Interface Builder. It looks as if you've set the top inset incorrectly; check your edge insets.
The reason your resizing code is not working is probably that it is too early (viewDidLoad); put it in viewDidAppear: and see if that works, and if it does, try moving it back to viewWillAppear: so the user doesn't see the resizing. If it doesn't work, it might be because you're using auto layout; you can't manually alter the frame of something whose frame is dictated by auto layout. (Your resizing code is also silly; you want to set the frame, not the bounds.) But it might also be because you're using a UITableViewController in a UINavigationController; if you do that, the table view is under the navigation controller's direct control and its size is not up to you.
I have following setup
XIB file which has only landscape view. This view is connection to my controller
There is a label on this view which is connected to IBOutlet UILabel* label
This label is configured like this (it occupies the whole width of screen).
I overrided viewWillAppear and do this (to get the size of label).
-(void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
CGRect rect = _labelTitleLand.frame;
}
The strange thing (which I don't understand). That it returns size = (width 768, height 21) when it launched in portrait (on iPad), which is correct.
And it returns size = (width 741 height 21) when it's launched in landscape. Which is weird. I anticipated that it will return width 1024, height 21 for landscape.
I was under impression that at the moment of viewWillAppear, all controls sizes are calculated already.
Update 1
If I check labelTitleLand.frame on viewDidAppear then it returns correct results. However, I don't like this, because I want to do some actions (based on this size) which influence how view will be drawn. In the case, if I will do it on viewDidAppear, as I understand there will be visible redrawing.
The layout of the view hierarchy has to be complete before you will get the actual final frames.
So you should check the frame in viewDidLayoutSubviews, which will still be before the view hierarchy is actually drawn. If you need to make changes here you can without causing any redrawing to occur.
viewWillAppear is too early because this is before your autoresizing masks (and/or autolayout constraints) have had their effect.
This seems a problem related to when a method is actually called at runtime.
I solved similar situation using
[self performSelector:#selector(checkMethod) withObject:nil afterDelay:0.1];
in viewWillAppear, and then:
- (void)checkMethod
{
rect = _labelTitleLand.frame;
}
This gives your app the time needed to set its own frame.
It is not so elegant and it looks like a workaround, but it is very effective.
You can also try to force the frame of the UIView that is container of the UILabel in viewWillAppear like this:
-(void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.view.frame = CGRectMake(0.0f, 0.0f, 1024.0f, 768.0f);
CGRect rect = _labelTitleLand.frame;
}
But the first solution is more reliable and usually no lag is experienced.
I have an iPad-application. In landscape orientation the UIViewController's view actual width = 1024px and height = 768 - 20 (statusBar) - 44 (navigationBar) = 704px.
So I wanna get this [1024 x 704] size and I'm using self.view.bounds for it. It returns [748 x 1024], which is wrong! But when I rotate the screen twice (current -> portrait -> current), the view's bounds are correct - [1024 x 704].
The view was initialized like this:
- (void)loadView {
self.view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
self.view.backgroundColor = [UIColor lightGrayColor];
}
And bounds were get like this:
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(#"bounds = %#", NSStringFromCGRect(self.view.bounds));
}
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
NSLog(#"bounds = %#", NSStringFromCGRect(self.view.bounds));
}
So the question is.. How can I get the correct view's bound in the very beginning?
How to do this correctly
Your UIViewController subclass should override the method viewWillLayoutSubviews, see also here.
When this method is called, the viewController's view has its correct size and you can make any necessary adjustments to subviews prior to the layout pass over the subviews.
Swift
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
NSLog("bounds = \(self.view.bounds)")
}
Obj-C
- (void)viewWillLayoutSubviews {
[super viewWillLayoutSubviews];
NSLog(#"bounds = %#", NSStringFromCGRect(self.view.bounds));
}
Documentation
When a view's bounds change, the view adjusts the position of its subviews. Your view controller can override this method to make changes before the view lays out its subviews. The default implementation of this method does nothing.
As you see from the emphasised part, this method is called every time the view controller's view changes size, as well as when the view first appears. This lets you respond correctly to rotation and other bounds change events
Several ways that don't work
A few approaches suggested in other answers don't work well, or have serious drawbacks. I urge you to avoid these approaches and I'll go through them to discuss the reasons you should avoid them.
viewDidLoad and viewWillAppear – during these calls view does not yet have its final size. The size you get will only ever be correct by pure chance, so as to mislead you.
viewDidAppear – this is too late. Your view is already on screen and visible to the user. Making changes here will cause visible changes / abrupt glitches and will look amateurish. Once again, please – for your sake, for my sake, for everyone's sake: don't do it! You're better than that and so are your users.
UIScreen.mainScreen.bounds.size – this is extremely low level. You're implementing a UIViewController and the size of its view depends on the controllers it is nested in (navigation, tab, paging, any custom controllers, etc), how the device is rotated, and potentially, how the screen has been split up for multitasking. So, while you might be able to compensate for all these and calculate the final size of your view, you'll end up with complex and brittle code that can easily break if Apple decide to change any of these metrics. UIViewController will do all this for you if you just override viewWillLayoutSubviews.
Other than not providing correct information, these problematic approaches will not help you with auto-rotation or other events that cause the view controller's view to change size, such as multitasking gestures. This is something you really want to handle smoothly.
So please: be a champ. Do it the right way. Use viewWillLayoutSubviews. Your implementation will be called for every size change, and your users, future self and team members will celebrate you for it. Bravo!
Further tips
When viewWillLayoutSubviews is called, the only view in your hierarchy that will be resized to its final size is viewController.view. The give away for this is in the name of the method. It's telling you view… (your view controller's root view) …WillLayout… (really soon now, but it's not happened yet) …Subviews (everything else in its hierarchy under the root view).
So subview layout has not happened yet. Every child under the root does not yet have a valid final size. Any size information you query from the child views will be at best completely wrong.
More likely, and enormously worse, it will be misleadingly correct.
It happens to be what you expect and need due to a default at this size and orientation, or due to your storyboard settings. But this is only by chance and isn't something you can rely on with different device sizes or orientations.
If you need to be told when a particular subview changes size, and know its exact final size, you should generally override the layoutSubviews method of that particular UIView subclass.
As per some of the other answers, the issue you are seeing is because viewDidLoad is called before the rotation happens. Because the iPad always initializes in portrait mode, if you get the size values in viewDidLoad, they will always be the portrait sizes - this is irrespective of any orientations you've configured.
To get the size after the orientation/rotation happens, get the size values in viewDidAppear.
I don't particularly understand why iOS doesn't handle this better - especially given that you define the orientations in the project settings, and, in Xcode Interface Builder. But, I'm sure there is a good reason ;-).
I've always used:
CGSize sizeOfScreen = [[UIScreen mainScreen] bounds].size;
to get the size of the screen, and:
CGSize sizeOfView = self.view.bounds.size;
to get the view's size. I have just tested it on viewDidLoad and it returned:
2012-07-17 10:25:46.562 Project[3904:15203] bounds = {768, 1004}
Which is correct since the CGSize is defined as {Width, Height}.
This is what I found in my last project: the frame of self.view will be adjusted after viewDidLoad according to if this screen has navigation bar etc.
So maybe you want to use that value after viewDidLoad (maybe in viewWillAppear or viewDidAppear) or adjust it manually by substract the height of bars.
I ran into this issue and found that getting the bounds in viewDidAppear worked for my needs.
If you want to get correct bounds of view in ViewDidLoad method, you can use Dispatch async with delay for it. See this example below:
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
// Get your bounds here
}
I'm building an iPad app with views that are split horizontally and animate in from the top and bottom (think of jaws sliding closed and open to appear and disappear respectively).
My problem is the layout of the custom jaws subview is broken only when the view loads in a landscape orientation. (The jaws-view container loads at the proper size, but the subsequent subviews for the top and bottom half are too tall, and going off the screen. They are the correct width though.)
I can start in portrait and then rotate and everything is arranged correctly.
I've tried setting the frame of the new view to the bounds of the original in a bunch of places (as suggested by many answers that didn't work for me, links upon request) but either haven't found the right spot, or need something more.
Do I need to do anything special to get the size to propagate? Is there a point before which I should not do animation? (I'm trying to move the top and bottom in my new view controller's viewDidLoad.)
The solution to this required 2 parts.
The first was described in this answer:
https://stackoverflow.com/a/8574519/1143123
which describes using viewWillAppear method instead of viewDidLoad (called earlier and "incorrect" values for bounds). This solved the problem of the view being layed out properly when loading that view in landscape (and propagated to subsequent rotations).
The second part was that the view could still get messed up if I started animating it and then did a rotation in the meantime. I changed my animation class to only move the center coordinate (as opposed to sliding the frame) which would have been better in the first place, but that didn't solve it. In the end I hardcoded the following in the ViewController for the class exhibiting these issues:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
[super didRotateFromInterfaceOrientation:fromInterfaceOrientation];
// The container view should match the size of the current view
gameView.frame = self.view.bounds;
CGFloat width = self.view.bounds.size.width;
if(roundInProgress) {
gameView.jawsTop.frame = CGRectMake(0, 0, width, self.view.bounds.size.height/2);
gameView.jawsBottom.frame = CGRectMake(0, self.view.bounds.size.height/2, width, self.view.bounds.size.height/2);
} else {
// If round not in progress, game cards should be offscreen
CGFloat height = self.view.bounds.size.height/2;
gameView.jawsTop.frame = CGRectMake(0, -height, width, height);
gameView.jawsBottom.frame = CGRectMake(0, self.view.bounds.size.height, width, height);
}
}
Without seeing your code my guess is that it has to do with the "Autoresize Subviews" property of your parent view and/or the autosizing set-up for your subviews. Try changing that property in Interface Builder to see if that fixes your issue.