Thursday, December 20, 2012

PageCurl bug from iOS 5.1 to 6.0

After bleeding too much of blood to solve crashing issue while trying to flip the first page(left side) and last page(right side) , finally i have come up with following solution. :)

OLD CODE(iOS 5.1) : when returning nil on the first and last page you will experience the app crash.It works fine in iOS 5.1,but in iOS 6 it wont.


- (UIViewController *)pageViewController:
(UIPageViewController *)pageViewController viewControllerBeforeViewController:
(UIViewController *)viewController
{
    for (UIGestureRecognizer *recognizer in pageController.gestureRecognizers) {
        if ([recognizer isKindOfClass:[UITapGestureRecognizer class]]) {
            recognizer.enabled = NO;
        }
    }
    NSUInteger index = [self indexOfViewController:
                        (MainViewController *)viewController];
    if ((index == 0) || (index == NSNotFound)) {
        return nil;
    }
    
    index--;
    return [self viewControllerAtIndex:index];
}
- (UIViewController *)pageViewController:
(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    for (UIGestureRecognizer *recognizer in pageController.gestureRecognizers) {
        if ([recognizer isKindOfClass:[UITapGestureRecognizer class]]) {
            recognizer.enabled = NO;
        }
    }
    NSUInteger index = [self indexOfViewController:
                        (MainViewController *)viewController];
    if (index == NSNotFound) {
        return nil;
    }
}

SOLUTION(iOS 6) : After adding the gesture effect to the superview,just call the delegate called -(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer. What i did is quiet simple, computing the speed of the user flipping the first page and last page (i mean using the gesture recognizer) , i denied the swiping.All you need to do is just paste the following code,and you are DONE!.

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    if (pageNum==0) {
        
        if ([(UIPanGestureRecognizer*)gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]] &&
            [(UIPanGestureRecognizer*)gestureRecognizer velocityInView:gestureRecognizer.view].x > 0.0f) {
            //NSLog(@"Swiping to left on 1st page is denied");
            return NO;
        }
        if ([(UITapGestureRecognizer*)gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]] &&
            [(UITapGestureRecognizer*)gestureRecognizer locationInView:gestureRecognizer.view].x < self.view.frame.size.width/2) {
         //NSLog(@"tapping to left on 1st page is denied");
            return NO;
        }
    }
    
    else if(pageNum ==totalNoOfFiles-1)
    {
        
        if ([(UIPanGestureRecognizer*)gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]] &&
            [(UIPanGestureRecognizer*)gestureRecognizer velocityInView:gestureRecognizer.view].x < 0.0f) {
            //NSLog(@"Swiping to right on 1st page is denied");
            return NO;
        }
        if ([(UITapGestureRecognizer*)gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]] &&
            [(UITapGestureRecognizer*)gestureRecognizer locationInView:gestureRecognizer.view].x > self.view.frame.size.width/2) {
          //NSLog(@"Tapping to right on 1st page is denied");
            return NO;
        }
    }
    
    return YES;
}


- (UIViewController *)pageViewController:(UIPageViewController*) pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
 {
  int index = [self indexOfViewController:(ChildViewController *)viewController];
                index--;
        
    return [self viewControllerAtIndex:index];
}


- (UIViewController *)pageViewController:
(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    int index = [self indexOfViewController:(ChildViewController *)viewController];
          
            index++;
     return [self viewControllerAtIndex:index];
}



Hope your life is saved :)

4 comments:

  1. yes,yu saved my life. .It would've been nice,if u had pasted the whole code

    ReplyDelete
  2. i did the same,though its not working for me.,control not passing to the delegate - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer..

    ReplyDelete
  3. Hi
    can you please share the App url in which you have implement this code ?

    ReplyDelete