UIPageViewController scroll automatically issue - ios

Question

I have implemented automatic scrolling of UIPageViewController after every 5 seconds using timer like this:
_bannerTimer = [NSTimer scheduledTimerWithTimeInterval:5.0
target:self
selector:#selector(loadNextController)
userInfo:nil
repeats:YES];
- (void)loadNextController
{
self.index++;
HeaderAdVC *nextViewController;
if(self.index>arrayImages.count-1)
{
self.index=0;
[pageIndicator setCurrentPage:0];
nextViewController = [self viewControllerAtIndex:0];
}
else
{
nextViewController = [self viewControllerAtIndex:self.index];
}
[pageIndicator setCurrentPage:self.index];
[pageController setViewControllers:#[nextViewController]
direction:UIPageViewControllerNavigationDirectionForward
animated:YES
completion:nil];
}
and removing the timer in viewWillDisappear
-(void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[_bannerTimer invalidate];
}
Problem :
My problem is when the loadNextController method is called my app stop responding.
If i switch to next page still getting the same problem on every view.

Answer 1

Do some changes like below , do all non-ui task in background thread and all UI operation in Main thread ,try this
- (void)loadNextController
{
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
self.index++;
HeaderAdVC *nextViewController;
if(self.index>arrayImages.count-1)
{
self.index=0;
[pageIndicator setCurrentPage:0];
nextViewController = [self viewControllerAtIndex:0];
}
else
{
nextViewController = [self viewControllerAtIndex:self.index];
}
dispatch_async(dispatch_get_main_queue(), ^{
[pageIndicator setCurrentPage:self.index];
[pageController setViewControllers:#[nextViewController]
direction:UIPageViewControllerNavigationDirectionForward
animated:YES
completion:nil];
});
});
}
i hope this will help you ..