I have an iphone app with 2 ViewControllers . Both screens(viewcontrollers) show a loading screen. I create the loading screen programmatically:
UIView *loadingScreen = [[UIView alloc] initWithFrame:CGRectMake(100,200,144,144)];
loadingScreen.center = CGPointMake(self.view.frame.size.width / 2.0, self.view.frame.size.height / 2.0);
//{.. Other customizations to loading screen
// ..}
[self.view addSubview:loadingScreen];
For some reason, the second viewcontroller's loadingScreen is significantly lower and it isn't centered on the screen. The first viewcontroller works perfectly and is dead center like I want.
The second viewcontroller is a UITableView and it shows the uinavigationbar, whereas the first viewcontroller doesn't show the uinavigationbar. Also, I use storyboard for my app.
I've outputted to the NSLog self.view.frame.size.height and loadingScreen.center in both instances and THEY HAVE THE SAME COORDINATES! So, not sure why it is showing up lower. Any ideas why the second loadingScreen is lower and how to fix? Thanks!
You mention that one screen displays a UINavigationBar while the other does not. When you display a navigation bar, it offsets the rest of your view - in this case by shifting it down.
There are two quick fixes. You can either adjust your center point up by the size of the UINavigationBar (65 pts - unless it's a custom UINavigationBar and you've changed its size) or you can set the "Adjust Scroll View Insets" value to false in the attributes inspector.
The latter is probably the easiest and comes most recommended. Note though, that the top of your UITableView will now be underneath the UINavigationBar.
My final note would be that if you wanted to do it programmatically than in your UITableView's delegate you can call
- (BOOL)automaticallyAdjustsScrollViewInsets
{
return NO;
}
Related
I started building a TableView in my app by using a TableViewController in a storyboard. When you do this, you have a very cool effect when you scroll down your list : the cells moving behind the nav bar get blurred.
Some time later, I had to move from this TableViewController to a ViewController with a TableView inside (I had to add other views at the bottom of the table).
In order to avoid having the first cells hidden by the navigation bar (being over it), I added constraints to the Top and Bottom Layout Guides, and to the left and right edges of the view.
This works fine, but I lost the cool blurred scrolling effect : the cells seem to be disappearing before going behind the navigation bar.
I've seen workarounds with people not using constraints and putting magic numbers in interface builder. I cannot do this, first because I dislike it, and second because I have to be iOS 6 compatible.
What did I miss to be able to benefit again from the blurred navigation bar effect ?
You have to manually adjust the contentInset of the table view and make sure the table view frame origin is 0, 0.
In this way the table view will be below the navigation bar, but there will be some margin between the content and the scroll view edges (the content gets shifted down).
I advise you to use the topLayoutGuide property of the view controller to set the right contentInsets, instead of hard coding 64 (status bar + navigation bar).
There's also bottomLayoutGuide, which you should use in case of UITapBars.
Here is some sample code (viewDidLoad should be fine):
// Set edge insets
CGFloat topLayoutGuide = self.topLayoutGuide.length;
tableView.contentInset = UIEdgeInsetsMake(topLayoutGuide, 0, 0, 0);
By the way, this properties of UIViewController might help you (you should not need to change their default values, but I don't know what your view hierarchy is):
automaticallyAdjustsScrollViewInsets
edgesForExtendedLayout
extendedLayoutIncludesOpaqueBars
The tableView needs to be full screen. That is underneath the top and bottom bars. Note don't use the top and bottom layout guides as they are used for positioning relative to the bars not underneath.
Then you need to manually set the content inset of the tableview. This sets the initial scroll position to under the top bar.
Something like:
CGSize statusBarSize = [[UIApplication sharedApplication] statusBarFrame].size;
CGFloat h=MIN(statusBarSize.width, statusBarSize.height);
UIEdgeInsets e = UIEdgeInsetsMake(self.navigationController.navigationBar.bounds.size.height + h,
0.0f,
0.0f,
0.0f);
self.tableView.contentInset = e;
Not you get this functionality for free when using a tableView controller and the "Automatically Adjust content inset" settings
You probably have the coordinates of your tableView not set to (0, 0) to map to those of the viewController.view.frame or viewController.view.bounds. If you have done that, try setting
self.navigationController.navigationBar.translucent = YES;
UIViewController property edgesForExtendedLayout does the trick. If you are using storyboards just make sure Extended Edges Under Top Bars is on (and it is by default).
If you are creating your view controller programmatically try this:
- (void)viewDidLoad
{
[super viewDidLoad];
self.edgesForExtendedLayout = UIRectEdgeAll;
}
And of course, your table view needs to have proper autoresizing mask/layout constraints
edgesForExtendedLayout is not what you want here, as this will limit the table view underneath the navigation bar. In iOS 7, the view controllers uses fullscreen by default, and the property controlling where the tableview content starts is automaticallyAdjustsScrollViewInsets. This should be YES by default, so check if it is somehow set to NO, or try setting it explicitly.
Check this answer for a good explanation on how this works:
https://stackoverflow.com/a/19585104/1485715
I have been reading a lot about iOS7 UI transition.
I am not able to get what these three properties automaticallyAdjustsScrollViewInsets, extendedLayoutIncludesOpaqueBars, edgesForExtendedLayout??
For example I am trying to make my view controllers start below the status bar but I am not able to achieve it.
Starting in iOS7, the view controllers use full-screen layout by default. At the same time, you have more control over how it lays out its views, and that's done with those properties:
edgesForExtendedLayout
Basically, with this property you set which sides of your view can be extended to cover the whole screen. Imagine that you push a UIViewController into a UINavigationController. When the view of that view controller is laid out, it will start where the navigation bar ends, but this property will set which sides of the view (top, left, bottom, right) can be extended to fill the whole screen.
Let see it with an example:
UIViewController *viewController = [[UIViewController alloc] init];
viewController.view.backgroundColor = [UIColor redColor];
UINavigationController *mainNavigationController = [[UINavigationController alloc] initWithRootViewController:viewController];
Here you are not setting the value of edgesForExtendedLayout, therefore the default value is taken (UIRectEdgeAll), so the view extends its layout to fill the whole screen.
This is the result:
As you can see, the red background extends behind the navigation bar and the status bar.
Now, you are going to set that value to UIRectEdgeNone, so you are telling the view controller to not extend the view to cover the screen:
UIViewController *viewController = [[UIViewController alloc] init];
viewController.view.backgroundColor = [UIColor redColor];
viewController.edgesForExtendedLayout = UIRectEdgeNone;
UINavigationController *mainNavigationController = [[UINavigationController alloc] initWithRootViewController:viewController];
And the result:
automaticallyAdjustsScrollViewInsets
This property is used when your view is a UIScrollView or similar, like a UITableView. You want your table to start where the navigation bar ends, because you wont see the whole content if not, but at the same time you want your table to cover the whole screen when scrolling. In that case, setting edgesForExtendedLayout to None won't work because your table will start scrolling where the navigation bar ends and it wont go behind it.
Here is where this property comes in handy, if you let the view controller automatically adjust the insets (setting this property to YES, also the default value) it will add insets to the top of the table, so the table will start where the navigation bar ends, but the scroll will cover the whole screen.
This is when is set to NO:
And YES (by default):
In both cases, the table scrolls behind the navigation bar, but in the second case (YES), it will start from below the navigation bar.
extendedLayoutIncludesOpaqueBars
This value is just an addition to the previous ones. By default, this parameter is set to NO. If the status bar is opaque, the views won't be extended to include the status bar, even if you extend your view to cover it (edgesForExtendedLayout to UIRectEdgeAll).
If you set the value to YES, this will allow the view to go underneath the status bar again.
If something is not clear, write a comment and I'll answer it.
How does iOS know what UIScrollView to use?
iOS grabs the first subview in your ViewController's view, the one at index 0, and if it's a subclass of UIScrollView then applies the explained properties to it.
Of course, this means that UITableViewController works by default (since the UITableView is the first view).
Not sure if you are using storyboards, but if you are, to make your view controllers start below the status bar (and above the bottom bar):
Select the view controller in IB,
In the attributes inspector, deselect 'Extend Edges - Under Top Bars' and 'Extend Edges - Under Bottom Bars'.
I am using storyboards and using the above advice worked however I wasn't exactly sure how to implement it. Below is a short example in swift of how it cleared up the problem by putting the recommended solution into the ViewController.
import Foundation
import UIKit
// This ViewController is connected to a view on a storyboard that
// has a scrolling sub view.
class TheViewController: UIViewController {
// Prepares the view prior to loading. Putting it in viewDidAppear didn't work.
override func viewWillAppear(animated: Bool) {
// this method is an extension of the UIViewController
// so using self works as you might expect.
self.automaticallyAdjustsScrollViewInsets = false
// Default is "true" so this sets it to false tells it to use
// the storyboard as you have it placed
// and not how it thinks it should place it.
}
}
My Problem:
Auto Adjust set to true by default causing a difference between storyboard design and simulator
Resolved:
Code above applied, turning off the auto-adjust.
I solved this problem by adding this line, but my problem was related to a UIView, not UIScrollView
self.navigationController.navigationBar.translucent = NO;
Just bare in mind that
automaticallyAdjustsScrollViewInsets
property works only if some kind of scroll view (table view, collection view,...) is either
The view of VC, or
First subview of this view
Other suggested, that it doest work even if it is the first subview, but there are other scroll views in the view hierarchy.
EDIT (extension DIY)
If you want similar behaviour even if you can't fulfil these conditions (e.g. you have a background image below the scroll view), you can adjust the scroll view insets manually. But please don't set it to constant like 44 or 64 or even 20 like many suggest around SO. You can't know the size ever. There can be the incall/gps/audio notification, navigation bar doesn't have to be always 44 pts etc.
I think the best solution is to use layoutGuide length in didLayoutSubviews:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
scrollView.contentInset = UIEdgeInsets(top: topLayoutGuide.length, left: 0, bottom: 0, right: 0)
scrollView.scrollIndicatorInsets = scrollView.contentInset
}
You can use the bottomLayoutGuide in the same way.
I get a weird interface bug with my UIScrollView and I cant figure out how to solve it. I only wrote one line of code (shown below) and it is a blank project's setup easily reproducible!
Setting:
I have a UIScrollView that contains a UISegmentedControl (since the segments of
the control are loaded dynamically, it could exceed the width of the screen and the scrollView is supposed to scroll the segmentedControl horizontally, the height of the scrollview is the same as the UISegmentedControl's).
The ViewController that contains this is embedded in a tabBar (or navigation bar, which also shows the bug). The whole thing is using Auto-Layout.
Bug:
When I scroll the SegmentedControl some degree to the right and then switch the viewController by clicking the other tab on the tabBarController, the content-offset of the segmented control gets weirdly shifted when switching back to the initial viewcontroller. When I try to scroll to the leftmost part of the scrollview it won't let me. When switching the tabs a couple of times, it gets fixed again and I can do this over.
What I did (can you reproduce this?):
Create a blank single-view ios project
Embed the already given viewController in a tabbarcontroller.
Put a scrollView on the upper portion of the view that fits the screen from left to right.
Put a UISegmentedControl on the topleft corner of the scrollview and drag the scrollview to fit the segmented controls height height
Change the Segmented control's width a bit so xcode adds a width-constraint. in the segmented control's width constraint change the width constraint's relation to "greater than or equal"
create an outlet to the segmented control
in viewDidload add this code
[self.segmentedControl insertSegmentWithTitle:#"A really long title so it you have to scroll to see it" atIndex: 0 animated: NO];
Create a blank viewcontroller and add it as a second viewController for the tabbarController.
This is how my storyboard looks like:
Now run the project, scroll the segmented control to it's right end as far as it goes. Switch the tab and switch back and please tell me how your scrollview now behaves - and WHY.
My guess would be it has something to do with Auto Layout maybe? Can't figure out what though.
I tried fixing this by setting the scrollView's contentSize in viewDidAppear or changing the content offset of the scrollView in viewDidAppear or changing frames, combination of those and what not....
Extra question:
Is it no longer neccessary to set the scrollViews contentSize property? Why does it scroll the content automatically?
After googeling I found the answer in another StackOverflow question.
What you need to do is save the scrollview.contentOffset on viewWillDisappear,
set it to CGPointZero on viewDidDisappear and set it back to the saved state on viewDidLayoutSubviews:
-(void) viewWillDisappear: (BOOL) animated {
self.lastContentOffset = self.scrollView.contentOffset;
[super viewWillDisappear: animated];
}
-(void) viewDidDisappear:(BOOL)animated {
[super viewDidDisappear: animated];
self.scrollView.contentOffset = CGPointZero;
}
- (void)viewDidLayoutSubviews {
[super viewDidlayoutSubviews];
self.scrollView.contentOffset = self.lastContentOffset;
}
This is a weird error that may just be an issue in Xcode for all I know. I have a tab bar controller where the first view is a UITableView with (obviously) a number of cells. When you select a cell, I've set up a segue on the MainStoryboard to go to a detail view controller. I want the tab bar to be hidden when I go to the detail view, so I went into the storyboard, chose my detail view, and clicked "Hides Bottom Bar on Push" in the editor screen that starts with "Simulated Metrics."
Everything works just fine, except that when I tap on a cell, a black bar flashes at the top of the UITableView screen, dropping the tableview cells down (as if the cells are falling down below the tab bar at the bottom), just before the screen pushes over to the detail view. The effect isn't harmful at all, but it's very disconcerting, and I'd like to smooth that out.
The only fix I've found is to uncheck the "Hides Bottom Bar when Pushed" option on the storyboard. That indeed does get rid of that black bar flash, but of course the tab bar stays on the screen when I go to the detail view, which is what I don't want.
Any ideas?
Just for completeness' sake, I went ahead and ran
[self.navigationController setToolbarHidden:YES animated: YES];
on the detail view controller's viewWillAppear method (and even tried it with the storyboard option both on and off), but there was no difference. The toolbar did indeed hide just fine, but I still got that black line at the top. So weird.
I know it is too late !!! I ran into same issue. It seems like the Auto resizing mask for the view was incorrect to be exact the UIViewAutoresizingFlexibleTopMargin. I checked this on in the xib file. If you are trying to do it in code make sure this flag -UIViewAutoresizingFlexibleTopMargin - is not included in the autoresizing mask.
Hope this will help some one in the future
I know it is a bit late, but I have same problem and I can't solve it with any of the previous answers. (I suppose this is the reason non was accepted).
The problem is that view size of the SecondViewController is same as view size of a previous ViewController, so too small to fit in a ViewController with Toolbar hidden. Thats why black background of a UITabBarController is visible at the top when transition is happening, and on a viewDidAppear view will stretch on right size.
For me it help to subclass root UITabBarController and set background color to same background color as SecondViewController has.
class RootViewController: UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = Style.backgroundColor
}
}
Then you can leave checkbox checked inside storyboard and it will look ok.
P.S.
If you have some views, that is position on the bottom part of the view, you need to set bottom constraints so they are smaller by 49 (because this is the height of the toolbar), and then on viewDidAppear set the right constraint.
For example:
I have view that need to be position 44 px from bottom edge. Before, I have constraint set to 44 and I have some strange behaviour of that view. It was placed to height and then jump on the right place.
I fix this with setting constraint to -5 (44-49), and then in viewDidAppear set the constraint back to 44. Now I have normal behaviour of that view.
Wow I just had the same issue now, very painful, and no info on the net about it.
Anyway, a simple workaround for me was to change the current view's Frame moving the y coordinates up and making the height bigger by the height of the tab bar. This fixed the problem if done straight after pushing the new view onto the navigation controller. Also, there was no need to fix the Frame afterwards (it must be updated when the view is shown again).
MonoTouch code:
UIViewController viewControllerToPush = new MyViewController();
viewControllerToPush.HidesBottomBarWhenPushed = true; // I had this in the MyViewController's constructor, doesn't make any difference
this.NavigationController.PushViewController(viewControllerToPush, true);
float offset = this.TabBarController.TabBar.Frame.Height;
this.View.Frame = new System.Drawing.RectangleF(0, -offset, this.View.Frame.Width, this.View.Frame.Height + offset);
Objective C code (untested, just a translation of the monotouch code):
UIViewController *viewControllerToPush = [MyViewController new];
viewControllerToPush.hidesBottomBarWhenPushed = YES; viewControllerToPush.hidesBottomBarWhenPushed = YES;
float offset = self.tabBarController.tabBar.frame.size.height; float offset = self.tabBarController.tabBar.frame.size.height;
self.view.frame = CGRectMake(0, -offset, self.view.frame.width, self.view.frame.height + offset); self.view.frame = CGRectMake(0, -offset, self.view.frame.size.width, self.view.frame.size.height + offset);
Do this in viewWillAppear of detailViewController, it should work fine
subclass your navigation controller, or just find the navigation bar
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
let backdropEffectView = navigationBar.subviews[0].subviews[0].subviews[0] //_UIBackdropEffectView
let visualEffectView: UIVisualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .Light))
visualEffectView.frame = backdropEffectView.frame
backdropEffectView.superview?.insertSubview(visualEffectView, aboveSubview: backdropEffectView)
backdropEffectView.removeFromSuperview()
}
I have a problem with top 20px behind status bar, specifically I cannot put anything there.
When I created the UI I used the storyboard approach and set status bar style to translucent black. But when do the layout in Xcode my views' height is fixed to 460px (grayed out).
Please help.
Got an answer from a friend, will mark his solution as right answer as soon as he posts it here. For now here is the solution:
In Interface Builder set up the view controller as wanting full screen and of freeform size: http://cl.ly/0x1p1u3q3B1y3b3C3U2n
Then in the view's size settings set its height to 480px: http://cl.ly/1p1b0e060p1Y37393D08
Ensure status bar style is translucent black in the Info.plist: http://cl.ly/153Y391S1b0G3J3z3Y1O
Get satisfactory result: http://cl.ly/0Q1M390i3A3h2F3u2T19
Here's solution without single line of code.
In Interface Builder set up the view controller as wanting full screen and of freeform size.
In the view's size settings set its height to 480px
Ensure status bar style is translucent black in the Info.plist.
Launch and observe
See the links for screenshots of each step in the top post.
Okay, having been told it's possible, I tried placing a view on top of the main view and setting its y coordinate to -20. Then I west to Info.plist and set Status bar style to Transparent black style (alpha of 0.5). The view I placed was visible beneath the status bar.
This only happened at run time; in Interface Buider the simulated translucent status bar is gray but opaque.
Edit: If you want to move your view controller's main view into this space, it is possible during viewWillAppear. (If you try to move it during viewDidLoad, it gets moved back afterwards.)
- (void)viewWillAppear:(BOOL)animated;
{
[super viewWillAppear:animated];
// Move the main view upwards if it isn't already there.
CGRect frame = [[self view] frame];
frame.size.height += frame.origin.y;
frame.origin.y = 0;
[[self view] setFrame:frame];
}
However, it gets moved back after rotation, and my attempts to respond to rotation ended up breaking the cell layout if I did this to a UITableView.
Here is the Swift version. Seems to work. Good solution for taking those App Store screen shots (well in addition to making the info.plist changes.
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
// Move the main view upwards if it isn't already there.
var frame: CGRect = self.view.frame
frame.size.height += frame.origin.y
frame.origin.y = 0
self.view.frame = frame
}
Just make negative Y (-20) coordinate in interface builder.
Try changing the value for "Status Bar" in the "Simulated Metrics" section of the Attributes inspector in Interface Builder. If you set it to "Inferred", Xcode will make no assumptions about the view controller, allowing you to set the size of the view to ANY size you want (even sizes that don't make any sense). Check out this post about the status bar for info on hiding it in your app.