ios8 iPad uiwebview crashes while displaying popover when user taps drop down list HTML select tag

Question

On ios8 and iPad if a uiwebview is displaying a HTML page containing a drop down list

eg this page http://www.w3schools.com/tags/tryit.asp?filename=tryh

Answer 1

The solution mentioned in the question did not help me, however it did point me in the right direction. After some investigation I would say it's some sort of race condition between presenting and removing the popover. As a workaround you can postpone the presentation in the delegate of the UIWebView:

-(void)presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion
{
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_USEC), dispatch_get_main_queue(),
               ^{
                   [super presentViewController:viewControllerToPresent animated:flag completion:completion];
               });
}

Answer 2

I had different exception in the same scenario, and none of workarounds from here helped me.

This was my exception:

Terminating app due to uncaught exception 'NSRangeException', reason: '-[UITableView _contentOffsetForScrollingToRowAtIndexPath:atScrollPosition:]: row (4) beyond bounds (0) for section (0).'

This is code I used to workaround it:

-(void)presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion {
    if ([viewControllerToPresent respondsToSelector:NSSelectorFromString(@"_cachedItems")]) {
        if([viewControllerToPresent valueForKey:@"_cachedItems"] == nil) {
            if (completion != nil) {
                completion();
            }
            return;
        }
    }

    [super presentViewController:viewControllerToPresent animated:flag completion:completion];
}

It's very nasty workaround that prevents from showing dropdown in cases when it's about to crash, and this solution can stop working in any time as it uses internal properties. However it was the only solution that worked for me so maybe it will be helpful for someone.

Answer 3

I have decreased the probability of occurrence of crash in this way.. Used javascript code and native ios

Web Side code changes

1. Register a 'click' event listener to your html component(drop down).
2. In the call back method send notification to native code. ex : "window.location='fromJavaScript://PopoverIssue'; "
3. It will call uiwebviews shouldStartLoadWithRequest

Native Side code changes

1. Implement UIPopoverPresentationControllerDelegate protocol on viewcontroller which has uiwebview and over ride popoverPresentationControllerShouldDismissPopover popoverPresentationControllerDidDismissPopover
2. put below code in shouldStartLoadWithRequest method of uiwebview for the above click notification

   [[UIApplication sharedApplication] beginIgnoringInteractionEvents];
       self.popoverPresentationController = self.presentedViewController.popoverPresentationController;
       self.existedPopoverDelegate = [self.popoverPresentationController delegate];
       self.popoverPresentationController.delegate = self;
       dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
       dispatch_async(queue, ^{
           int64_t delay = 2.0;
           dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, delay * NSEC_PER_SEC);
           dispatch_after(time, dispatch_get_main_queue(), ^{
               if([[UIApplication sharedApplication] isIgnoringInteractionEvents])
               {
                   [[UIApplication sharedApplication] endIgnoringInteractionEvents];
               }
           });
       });

3. implement the overridden protocol methods as follows

   
   
   
   (BOOL)popoverPresentationControllerShouldDismissPopover:(UIPopoverPresentationController *)popoverPresentationController
   {
   [self.existedPopoverDelegate popoverPresentationControllerShouldDismissPopover:popoverPresentationController];
   return YES;
   }
   (void)popoverPresentationControllerDidDismissPopover:(UIPopoverPresentationController *)popoverPresentationController
   {
   [self.existedPopoverDelegate popoverPresentationControllerDidDismissPopover:popoverPresentationController];
   dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
   dispatch_async(queue, ^{
   int64_t delay = 2.0;
   dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, delay * NSEC_PER_SEC);
   dispatch_after(time, dispatch_get_main_queue(), ^{
       if([[UIApplication sharedApplication] isIgnoringInteractionEvents])
       {
           [[UIApplication sharedApplication] endIgnoringInteractionEvents];
       }
   });
   });
   }