I am trying to display a modal viewController in an iPad app using the UIModalPresentationFormSheet view style. I am looking to produce something similar to the Mail app's new message UI/animation.
There are two things that are not behaving correctly:
The modal viewController that is presented always animates to y=0, i.e. to the very top of the
view and not some pixels below the status bar as it does in the mail app.
The documentation says:
UIModalPresentationFormSheet The width
and height of the presented view are
smaller than those of the screen and
the view is centered on the screen. If
the device is in a landscape
orientation and the keyboard is
visible, the position of the view is
adjusted upward so that the view
remains visible. All uncovered areas
are dimmed to prevent the user from
interacting with them.
However, in my case there is no dimming and I can still interact with the parentView below the modalViewController.
The controller that presents the modalView I do this:
AddNewItemViewController *newItemViewController = [[AddNewItemViewController alloc] initWithNibName:#"AddNewItemViewController" bundle:nil];
[self presentModalViewController:newItemViewController animated:YES];
[newItemViewController release];
In the viewController being presented I do this:
- (void)viewDidLoad {
[nameField becomeFirstResponder];
[self setModalTransitionStyle:UIModalTransitionStyleCoverVertical];
[self setModalPresentationStyle:UIModalPresentationFormSheet];
[super viewDidLoad];
}
I hope someone can help me out.
Is there some other properties I need to set on the parent and modalViewController?
Is the viewDidLoad not the right place to do this setup?
Thanks in advance:)
You set the transition and presentation styles when you create the modal view, before you call presentModalViewController. Remember, the view that creates the modal view 'owns' that object. You want the owner to set these properties because you might implement this modal view elsewhere in the app and want different transition or presentation styles. This way, you set it each time as appropriate.
AddNewItemViewController *newItemViewController = [[AddNewItemViewController alloc] initWithNibName:#"AddNewItemViewController" bundle:nil];
newItemViewController.modalPresentationStyle = UIModalPresentationFormSheet;
[self presentModalViewController:newItemViewController animated:YES];
[newItemViewController release];
You're right in calling becomeFirstResponder in viewDidLoad.
Related
I am updating our app to be compiled with xcode6/iOS8.
One issue I am running into is that when a modal view is presented. the underlying subview is removed. It is completely blacked out.. until the modal view is dismissed.. then it re-appears.
Has anyone run into this with iOS8? The same code has worked since iOS4.
Code:
PigDetailViewController *pigDetailViewController = [[PigDetailViewController alloc] initWithNibName:#"PigDetailViewController" bundle:nil];
self.navigationController.modalPresentationStyle = UIModalPresentationCurrentContext;
self.navigationController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:pigDetailViewController animated:YES completion:nil];
In iOS 8 they've added a new presentation style that behaves like UIModalPresentationCurrentContext in the circumstance you've described, it's UIModalPresentationOverCurrentContext. The catch here is that unlike with UIModalPresentationCurrentContext, you want to set the view controller to be PRESENTED with this presentation style, like so:
PigDetailViewController *pigDetailViewController = [[PigDetailViewController alloc] initWithNibName:#"PigDetailViewController" bundle:nil];
pigDetailViewController.modalPresentationStyle = UIModalPresentationOverCurrentContext;
self.navigationController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:pigDetailViewController animated:YES completion:nil];
Note that to support iOS 7 and below you'll likely need to check the OS version and decide how to present the view controller based on that.
edit: I'd like to add one more note to this. In iOS7 with UIModalPresentationCurrentContext, when the presented VC was dismissed, the underlying VC had its viewDidAppear method called. In iOS8 with UIModalPresentationOverCurrentContext, I've found the underlying VC does not have its viewDidAppear method called when the VC presented over top of it is dismissed.
Adding a point to BrennanR's answer.. even viewWillAppear doesn't call when the VC presented over top of it is dismissed.
I think you are misunderstanding how a modal view controller works.
When you present a view controller modally it will control the entire screen. It has an opaque background (normally black) and then draws its view on top of that.
So, if you set the view.backgroundColor to yellow (for example) it will have a yellow background. If you set it to clear then it will show through to the black background.
What I think you want is for the other view to "show through" so it looks like the modal view is sitting on top of it.
The best way I have found of doing this is to use this method...
// in the view controller that is presenting the modal VC
modalVC = // the modal VC that you will be presenting
UIView *snapshotView = [self.view snapshotViewAfterScreenUpdates:NO];
[modalVC.view insertSubView:snapshotView atIndex:0];
// present the modal VC
This will take a "screenshot" of the current view hierarchy and then place that snapshot underneath everything in the modal VC.
That way your black screen will be replaced by a screenshot of the previous view controller.
I am trying to add custom UIViewController on top of everything but not covering full screen (basically popover), like this:
- (void) displayPopoverController: (UIViewController*) content;
{
[self addChildViewController:content];
content.view.frame = [self frameForContentController];
[self.view addSubview:content.view];
[content didMoveToParentViewController:self];
}
Everything works, but unfortunately it is underneath the navigation bar. So I decided to add UIViewController to the navigation controller like this:
- (void) displayPopoverController: (UIViewController*) content;
{
[self.navigationController addChildViewController:content];
content.view.frame = [self frameForContentController];
[self.navigationController.view addSubview:content.view];
[content didMoveToParentViewController:self.navigationController];
}
It worked, but there are 2 problems:
1) viewWillAppear is not called when I add popover (only viewDidLoad is called)
2) If I change orientation, my popover receives notification and adjusts to new orientation, but UIViewController behind it does not. It will only update its view after I remove popover.
Is there any way to fix 1 and 2? Maybe there is better approach(I don't want to use UIPopoverController with custom UIPopoverBackgroundView)?
IMO you should make a custom transition and present UIViewController modally.
You can get help on Custom UIViewController transition here : http://www.doubleencore.com/2013/09/ios-7-custom-transitions/
I am trying to add custom UIViewController on top of everything but not covering full screen
If you can confine yourself to iOS 7, your problems are over. You can use presentViewController: and a custom transition to do exactly what you are trying to do. This, in my view, is the most important new feature of iOS 7: you can present a view controller's view only partially covering the main interface.
See my book; for the particular example code from the book, see https://github.com/mattneub/Programming-iOS-Book-Examples/blob/master/bk2ch06p304customPresentedAnimation2/ch19p620customPresentedAnimation2/ViewController2.m
Plus I've now posted a single project at https://github.com/mattneub/custom-alert-view-iOS7. It shows how to make a view controller presented view that only partially covers the interface, plus it demonstrates that device rotation works correctly for all visible views (i.e. what's in front and what's visible behind).
I have an iOS application using storyboards where I display a view controller that I create from an .xib file to the user. This view controller accepts some user input, but I then have to dismiss it and return to the main application. I am able to display the view controller, which also has a button that calls a method to dismiss the view controller. My problem is that after the user presses the button to go back to the main application, the entire screen goes black. Here is my code for the button from the .xib view controller that is trying to remove itself from the display:
- (IBAction)myButtonAction:(id)sender {
[self.view removeFromSuperview];
}
Here is the code from my main application's view controller which calls the .xib view Controller in the first place:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
_nextView = [[NextLandscapeViewController alloc] initWithNibName:#"NextLandscapeViewController" bundle:nil];
[_nextView setDelegate:(id)self];
NextNavigationController *navigationController = [[NextNavigationController alloc] initWithRootViewController:_nextView];
[self presentViewController:navigationController animated:YES completion:nil];
}
NextNavigationController is a subclass of UINavigationController which I do for the purpose of loading _nextView in landscape mode instead of portrait mode. This part is working fine. My concern now is dismissing this viewController after the user is finished working with it, and return back to the calling view controller in the main application.
Is there any reason why my screen is black? How I can resolve this issue?
Don't use removeFromSuperview, use [self dismissViewControllerAnimated:YES completion:nil]; Just like you use a pop to undo a push, you use dismissViewController to undo a presentViewController. The reason you get a black screen is because presenting a view controller removes the view of the presenting view controller from the window's hierarchy. So, when you remove the view from the superview, there's nothing underneath but the window.
So in my universal app I have a section where a person can look at an existing list of notes from our system (retrieved through a simple web service) and then also create a new note if they want. So for the iphone it's pretty simple layout, a TableViewController for displaying the list with a "Add" button on the NavigationBar that presents the modalview for adding the new item. On the iPad though, the same layout has a lot of wasted space so I opted to go with the popOver method to show the list in a popOver and then let them add from there. My problem is that when the user clicks on the Add button within the PopOver view, the modal view comes up full screen instead of just coming up within the popover view. Here's the code I have so far:
-(void) AddButtonPressed:(id)sender {
NewNoteVC *newNote = [[[NewNoteVC alloc] initWithNibName:#"NewNoteVC" bundle:nil] autorelease];
newNote.defaultClientID = defaultClientID;
UINavigationController *navCon = [[[UINavigationController alloc] initWithRootViewController:newNote] autorelease];
if ([isPopOver isEqualToString:#"YES"]) {
[navCon setModalInPopover:YES];
[self.navigationController setModalInPopover:YES];
[self.navigationController presentModalViewController:navCon animated:YES];
}
else {
[self.navigationController presentModalViewController:navCon animated:YES];
}
}
The "isPopOver" string is just a placeholder sent from the previous screen that called this TableView (I know I can switch this to a boolean for better performance I just put this together real quick to try it out). I know I messed up somewhere, I just don't know what setting I need to get this working correctly.
You need to define the view controller's modalPresentationStyle to be "current context".
navCon.modalPresentationStyle = UIModalPresentationCurrentContext;
This will result in modal view controller filling the popover like the popover's root controller.
Try using the presentViewController:animated:completion: instead of presentModalViewController:animated: and set self.navigationController.definesPresentationContext = YES
I am trying to get a popup effect and want to design the popup view in another view controller so i can use the xib to do it.
When i used the presentViewController or pushViewController and set the background to transparent, i end up seeing the Window's background color.
I tried this code to add subview to the navigation controller's view so that i can have the Info view cover the entire screen with a transparent background. I also have tab bar to cover up as well.
InfoVC *vc = [[InfoVC alloc] initWithNibName:#"InfoVC" bundle:nil];
[self.navigationController.view addSubview:vc.view];
My problem is inside my InfoVC when i try to dismiss it, the app will crash with some EXC_BAD_ACCESS message:
[self.view removeFromSuperview];
EDIT:
I found a way to stop it crashing but setting the InfoVC as a property in the MainVC. I think the reason for crash is when i call "self.view" in the action inside the InfoVC, it doesn't know that self is the InfoVC inside MainVC.
InfoVC *vc = [[InfoVC alloc] initWithNibName:#"InfoVC" bundle:nil];
[self.navigationController.view addSubview:vc.view];
No no no no. Never never do that.
There is an elaborate dance that you must traverse in order to put a view controller's view inside another view controller's view (or remove it afterwards) if it doesn't come with built-in facilities for doing this (the way a UISplitViewController does, or the way a navigation controller manages the views of the view controllers that are pushed and popped within it).
Read up on customer container controllers. One of the examples from my book is here:
https://github.com/mattneub/Programming-iOS-Book-Examples/blob/master/ch19p556containerController/p476containerController/ViewController.m
Shouldn't you be using the following to remove the view from its superview?
[vc.view removeFromSuperview];
You can never have a UIView remove it's subviews, the subviews themselves must remove themselves from it's superview. You can easily loop through subviews and have them removed like so
for (UIView *view in vc.view.subviews) {
[view removeFromSuperview];
}
Docs for reference:
http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html
After a "modally" presented view controller has appeared the views under the now presented view controller will be removed; this saves memory, and eases rendering. In your case, though, you also end up seeing the window behind the "modally" presented view.
The natural, and seemingly logical, next step is to simply take one view controller's view and cram it into another. However, as you have discovered, this is problematic. With the newly inserted view safely retained by the view hierarchy it is safe, but the new view controller is not so lucky, it is quickly deallocated. So when this new view tries to contact its controller you will get an EXC_BAD_ACCESS and crash. One workaround, again as you have found, is to simply have the original view controller keep a strong reference to the new view controller. And this can work... badly. There's still a good chance you will get an UIViewControllerHierarchyInconsistencyException.
Of course if you simply want to add a small view you create in IB you don't need to use a view controller as the "File's Owner" and there are many examples of creating an instance of a view from a xib file.
The more interesting question here is, "How would/does apple do it?" Apple consistently says that a view controller is the correct controller for an encapsulated unit of work. For example, their TWTweetComposeViewController, you present it, and it seems to float. How?
The first way of accomplishing this that comes to my mind is to have a clear background that isn't clear. That is, create an image of the screen before the presented view controller appears and set that as the background before the presenting view is removed. So for example(Explanation to follow):
QuickSheetViewController.xib
QuickSheetViewController.h
#import <UIKit/UIKit.h>
#interface QuickSheetViewController : UIViewController
- (IBAction)dismissButtonPressed:(id)sender;
#end
QuickSheetViewController.m
#import "QuickSheetViewController.h"
#import <QuartzCore/QuartzCore.h>
#implementation QuickSheetViewController {
UIImage *_backgroundImage;
}
-(void)renderAndSaveBackgroundImageFromVC:(UIViewController *)vc{
UIGraphicsBeginImageContext(vc.view.bounds.size);
[vc.view.layer renderInContext:UIGraphicsGetCurrentContext()];
_backgroundImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
-(void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
// save an image of the current view, and set our background to clear so we can see the slide-in.
[self renderAndSaveBackgroundImageFromVC:self.presentingViewController];
self.view.backgroundColor = [UIColor clearColor];
}
-(void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
// Time to use our saved background image.
self.view.backgroundColor = [UIColor colorWithPatternImage:_backgroundImage];
}
-(void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
// Set our background to clear so we can see the slide-out.
self.view.backgroundColor = [UIColor clearColor];
}
- (IBAction)dismissButtonPressed:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#end
The majority of this example hinges upon the renderAndSaveBackgroundImageFromVC: method. In which, we create a graphics context render the view we are about to cover into it, and then create a UIImage to later (in viewDidAppear) use as a background.
Now simply use it like:
QuickSheetViewController *newVC = [[QuickSheetViewController alloc] initWithNibName:nil bundle:nil];
[self presentViewController:newVC animated:YES completion:nil];
You will see through the background just long enough for the animation to happen, then we use our saved image to hide the removal of the presenting view.