How to Dismiss a Storyboard Popover

问题:

I've created a popover from a UIBarButtonItem using Xcode Storyboards (so there's no code) like this:

Presenting the popover works just fine. However, I can't get the popover to disappear when I tap the UIBarButtonItem that made it appear.

When the button is pressed (first time) the popover appears. When the button is pressed again (second time) the same popover appears on top of it, so now I have two popovers (or more if I continuer pressing the button). According to the iOS Human Interface Guidelines I need to make the popover appear on the first tap and disappear on the second:

Ensure that only one popover is visible onscreen at a time. You should not display more than one popover (or custom view designed to look and behave like a popover) at the same time. In particular, you should avoid displaying a cascade or hierarchy of popovers simultaneously, in which one popover emerges from another.

How can I dismiss the popover when the user taps the UIBarButtonItem for a second time?

回答1:

EDIT: These problems appear to be fixed as of iOS 7.1 / Xcode 5.1.1. (Possibly earlier, as I haven't been able to test all versions. Definitely after iOS 7.0, since I tested that one.) When you create a popover segue from a UIBarButtonItem, the segue makes sure that tapping the popover again hides the popover rather than showing a duplicate. It works right for the new UIPresentationController-based popover segues that Xcode 6 creates for iOS 8, too.

Since my solution may be of historical interest to those still supporting earlier iOS versions, I've left it below.

---

If you store a reference to the segue's popover controller, dismissing it before setting it to a new value on repeat invocations of prepareForSegue:sender:, all you avoid is the problem of getting multiple stacking popovers on repeated presses of the button -- you still can't use the button to dismiss the popover as the HIG recommends (and as seen in Apple's apps, etc.)

You can take advantage of ARC zeroing weak references for a simple solution, though:

1: Segue from the button

As of iOS 5, you couldn't make this work with a segue from a UIBarButtonItem, but you can on iOS 6 and later. (On iOS 5, you'd have to segue from the view controller itself, then have the button's action call performSegueWithIdentifier: after checking for the popover.)

2: Use a reference to the popover in -shouldPerformSegue...

@interface ViewController
@property (weak) UIPopoverController *myPopover;
@end

@implementation ViewController
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // if you have multiple segues, check segue.identifier
    self.myPopover = [(UIStoryboardPopoverSegue *)segue popoverController];
}
- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender {
    if (self.myPopover) {
        [self.myPopover dismissPopoverAnimated:YES];
        return NO;
    } else {
        return YES;
    }
}
@end

3: There's no step three!

The nice thing about using a zeroing weak reference here is that once the popover controller is dismissed -- whether programmatically in shouldPerformSegueWithIdentifier:, or automatically by the user tapping somewhere else outside the popover -- the ivar goes to nil again, so we're back to our initial state.

Without zeroing weak references, we'd have to also:

• set myPopover = nil when dismissing it in shouldPerformSegueWithIdentifier:, and
• set ourself as the popover controller's delegate in order to catch popoverControllerDidDismissPopover: and also set myPopover = nil there (so we catch when the popover is automatically dismissed).

回答2:

I found the solution here https://stackoverflow.com/a/7938513/665396 In first prepareForSegue:sender: store in a ivar/property the pointer to the UIPopoverController and user that pointer to dismiss the popover in the subsequent invocations.

...
@property (nonatomic, weak) UIPopoverController* storePopover;
...

- (void)prepareForSegue:(UIStoryboardSegue *)segue 
                 sender:(id)sender {
if ([segue.identifier isEqualToString:@"My segue"]) {
// setup segue here

[self.storePopover dismissPopoverAnimated:YES];
self.storePopover = ((UIStoryboardPopoverSegue*)segue).popoverController;
...
}

回答3:

I've used custom segue for this.

1

create custom segue to use in Storyboard:

@implementation CustomPopoverSegue
-(void)perform
{
    // "onwer" of popover - it needs to use "strong" reference to retain UIPopoverReference
    ToolbarSearchViewController *source = self.sourceViewController;
    UIViewController *destination = self.destinationViewController;
    // create UIPopoverController
    UIPopoverController *popoverController = [[UIPopoverController alloc] initWithContentViewController:destination];
    // source is delegate and owner of popover
    popoverController.delegate = source;
    popoverController.passthroughViews = [NSArray arrayWithObject:source.searchBar];
    source.recentSearchesPopoverController = popoverController;
    // present popover
    [popoverController presentPopoverFromRect:source.searchBar.bounds 
                                       inView:source.searchBar
                     permittedArrowDirections:UIPopoverArrowDirectionAny
                                     animated:YES];

}
@end

2

in view controller that is source/input of segue e.g. start segue with action:

-(void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar
{
    if(nil == self.recentSearchesPopoverController)
    {
        NSString *identifier = NSStringFromClass([CustomPopoverSegue class]);
        [self performSegueWithIdentifier:identifier sender:self];
    } 
}

3

references are assigned by segue which creates UIPopoverController - when dismissing popover

-(void)searchBarTextDidEndEditing:(UISearchBar *)searchBar
{
    if(self.recentSearchesPopoverController)
    {
        [self.recentSearchesPopoverController dismissPopoverAnimated:YES];
        self.recentSearchesPopoverController = nil;
    }    
}

regards, Peter

回答4:

I solved it creating a custom ixPopoverBarButtonItem that either triggers the segue or dismisses the popover being shown.

What I do: I toggle the action & target of the button, so it either triggers the segue, or disposes the currently showing popover.

It took me a lot of googling for this solution, I don't want to take the credits for the idea of toggling the action. Putting the code into a custom button was my approach to keep the boilerplate code in my view to a minimum.

In the storyboard, I define the class of the BarButtonItem to my custom class:

Then I pass the popover created by the segue to my custom button implementation in the prepareForSegue:sender: method:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender  
{
    if ([segue.identifier isEqualToString:@"myPopoverSegue"]) {
        UIStoryboardPopoverSegue* popSegue = (UIStoryboardPopoverSegue*)segue;
        [(ixPopoverBarButtonItem *)sender showingPopover:popSegue.popoverController];
    }
}

Btw... since I have more than one buttons triggering popovers, I still have to keep a reference of the currently displayed popover and dismiss it when I make the new one visible, but this was not your question...

Here is how I implemented my custom UIBarButtonItem:

...interface:

@interface ixPopoverBarButtonItem : UIBarButtonItem

- (void) showingPopover:  (UIPopoverController *)popoverController;

@end

... and impl:

#import "ixPopoverBarButtonItem.h"
@interface ixPopoverBarButtonItem  ()
@property (strong, nonatomic) UIPopoverController *popoverController;
@property (nonatomic)         SEL                  tempAction;           
@property (nonatomic,assign)  id                   tempTarget; 

- (void) dismissPopover;

@end

@implementation ixPopoverBarButtonItem

@synthesize popoverController = _popoverController;
@synthesize tempAction = _tempAction;
@synthesize tempTarget = _tempTarget;

-(void)showingPopover:(UIPopoverController *)popoverController {

    self.popoverController = popoverController;
    self.tempAction = self.action;
    self.tempTarget = self.target;
    self.action = @selector(dismissPopover);
    self.target = self;
}    

-(void)dismissPopover {
    [self.popoverController dismissPopoverAnimated:YES];
    self.action = self.tempAction;
    self.target = self.tempTarget;

    self.popoverController = nil;
    self.tempAction = nil;
    self.tempTarget = nil;
}


@end

ps: I am new to ARC, so I am not entirely sure if I am leaking here. Please tell me if I am...

回答5:

I have solved this problem with no need to keep a copy of a UIPopoverController. Simply handle everything in storyboard (Toolbar, BarButtons. etc.), and

• handle visibility of the popover by a boolean,
• make sure there is a delegate, and it is set to self

Here is all the code:

ViewController.h

@interface ViewController : UIViewController <UIPopoverControllerDelegate>
@end

ViewController.m

@interface ViewController ()
@property BOOL isPopoverVisible;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.isPopoverVisible = NO;
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // add validations here... 
    self.isPopoverVisible = YES;
    [[(UIStoryboardPopoverSegue*)segue popoverController] setDelegate:self];
}

- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender {
    return !self.isPopoverVisible;
}

- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController {
    self.isPopoverVisible = NO;
}
@end

回答6:

I took rickster's answer and packaged it into a class derived from UIViewController. This solution does require the following:

• iOS 6 (or later) with ARC
• Derive your view controller from this class
• make sure to call the "super" versions of prepareForSegue:sender and shouldPerformSegueWithIdentifier:sender if you are overriding those methods
• Use a named popover segue

The nice thing about this is you don't have to do any "special" coding to support the proper handling of Popovers.

Interface:

@interface FLStoryboardViewController : UIViewController
{
    __strong NSString            *m_segueIdentifier;
    __weak   UIPopoverController *m_popoverController;
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender;
- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender;
@end

Implementation:

@implementation FLStoryboardViewController

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if( [segue isKindOfClass:[UIStoryboardPopoverSegue class]] )
    {
        UIStoryboardPopoverSegue *popoverSegue = (id)segue;

        if( m_popoverController  ==  nil )
        {
            assert( popoverSegue.identifier.length >  0 );    // The Popover segue should be named for this to work fully
            m_segueIdentifier   = popoverSegue.identifier;
            m_popoverController = popoverSegue.popoverController;
        }
        else
        {
            [m_popoverController dismissPopoverAnimated:YES];
            m_segueIdentifier = nil;
            m_popoverController = nil;
        }
    }
    else
    {
        [super prepareForSegue:segue sender:sender];
    }
}


- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender
{
    // If this is an unnamed segue go ahead and allow it
    if( identifier.length != 0 )
    {
        if( [identifier compare:m_segueIdentifier]  ==  NSOrderedSame )
        {
            if( m_popoverController == NULL )
            {
                m_segueIdentifier = nil;
                return YES;
            }
            else
            {
                [m_popoverController dismissPopoverAnimated:YES];
                m_segueIdentifier = nil;
                m_popoverController = nil;
                return NO;
            }
        }
    }

    return [super shouldPerformSegueWithIdentifier:identifier sender:sender];
}

@end

Source available on GitHub