Strange top spacing for ScrollView - ios

I settled the scrollview and the image should be at the top.
But when I pushed this view on navigation controller it adds some strange spacing at the top
if let destination = self.storyboard?.instantiateViewControllerWithIdentifier(StoryboardNames.ItemDetailsView.rawValue) as? ItemDetailsViewConroller {
destination.itemEntity = updatedItem
self.navigationVC?.pushViewController(destination, animated: true)
}
But, I'm opening this view from different navigation controllers.
From first the sizing is correct (no spacing at the top), but from another I receive this strange bug.
Does anyone know why this is caused?

write this below line in your viewDidLoad method:
self.automaticallyAdjustsScrollViewInsets = false

Uncheck Scrollview insets in storyboard

This thing will be happening if and only if you are adding ScrollView or its subclass(tableview,collectionView,textview etc) at first position in viewController's main view. You can move it to second or any other position or solve by doing following thing:
select your viewcontroller, and see its layout attribute as shown in following image, here uncheck the "Adjust Scroll View Insets". This will stop adding 20 pixel space above.

Related

Scrollview Autolayout with Tabbar and Navigationbar

I need to set constraints in uiscrollview in viewcontroller containing navigationbar and tabbar.I have placed a uiview(contentView) inside scrollview which is of same height as of scrollview.These are the things which I have set curently,
set 4 constraints for scrollview(top,bottom,left,right) with
constraints to margin unchecked which is 0 for all edges.
set 4 constraints for uiview(contentView) inside
scrollview(top,bottom,left,right) with constraints to margin
unchecked which is 0 for all edges.
set equal width and equal height
for scrollview and UIView(contentView)
output is displaying like this uiview(contentView) gets placed lower about 64 px (approx).This view should not place like this.Can anyone help me to solve this.
Here is the project demo which I have worked and can be downloaded here
Select the scene and in the attributes inspector, uncheck: "Under Top Bars" and "Under Bottom Bars".
Then in the storyboard make the scroll view start at the very top of the View Controller, where the navigation bar starts, and then the UIView, where the navigation Bar ends.
Later, select the Scroll View and set the constraints as they come by default.
I guess it's not the cleanest way to do it but I had the same issue and worked for me.
You might try self.automaticallyAdjustsScrollViewInsets = false
The Tab Bar has to be set in the tree UNDER the scrollView, like this:
Try this
override func viewDidLoad() {
self.edgesForExtendedLayout = UIRectEdge()
self.extendedLayoutIncludesOpaqueBars = false
}
I have found the solution for it,The parent ViewController class is set to under top bar and disabling it and changed the frame accordingly in the parent and set the same property and frame to child viewcontroller fixed the issue.

Empty white space above UITableView inside a UIView

I'm trying to position a TableView inside my ViewController view but leaving a 44 height gap between the bottom of the navigation bar and the top of the table. I then wanted to place a UITextField inside that gap to act as a stationary header. For some reason, the TableView has an empty white space above the start of the "Prototype Cells". Its just white space. Here is what it looks like in the storyboard.
When viewing the app display, this is what it looks like:
When scrolling the table, it goes all the way up to the correct place:
Try to look in the 'attribute inspector' (in the right menu) of the Participants ViewController.
Check for the option 'Extend Edges' and uncheck the 'Under Top Bars', and then relocate your tableview.
Another possible solution is to just uncheck the option 'Adjust Scroll View Insets'.
The reason is that when the viewController extends its edges, let's say under the top bar, the tableView's scrollView automatically adjusts its inset top, so that the content of the tableView will start exactly under the top bar. But in your case this is not needed, since your tableView itself starts under the bar.
Focus on the ViewController and got to the Attribute Inspector tab:
Try this one:
self.tableView.contentInset = UIEdgeInsetsMake(-65, 0, 0, 0)
Just add this in you ViewDidLoad method
self.automaticallyAdjustsScrollViewInsets = NO;
change your table view style from grouped to plain
You should not need to change the default setting for Extend Edges.
Looks like the real problem is a blank table header view in your storyboard. It's showing in the screenshot you provided of your storyboard, right below the Enter Name view and right above the Prototype Cells view. Delete it.
My issues is, I set tableHeaderView as new UIView like this
self.tableHeaderView = UIView(frame: .zero)
Remove this line, the issue is gone. Try this:
//self.tableHeaderView = UIView(frame: .zero)
This is the 2022, iOS 15 solution if anyone stumbles upon this.
if #available(iOS 15.0, *) {
UITableView.appearance().sectionHeaderTopPadding = CGFloat(0)
}
I just found a solution for this.
In my case, i was using TabBarViewController, A just uncheck the option 'Adjust Scroll View Insets'. Issues goes away.
https://i.stack.imgur.com/qgQI8.png
For Objective-C folks, add this in your ViewDidLoad method.
[self.tableView setContentInset:UIEdgeInsetsMake(-20, 0, 0, 0)];

iOS 7 TableView in a ViewController and NavigationBar blurred effect

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

Weird interface bug UIScrollView in UITabBarController. Reproducible by others?

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;
}

Black bar flashes at top of UITableView when pushing to view with "Hides Bottom Bar When Pushed" in IB

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()
}

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