Draw a path above UIPageViewController

Question

I am now creating an application for kids.This application uses "UIPageViewController". Kids can draw lines inside pages by dragging their fingers.

The problem is that when drag above page that page get flipped: how I can disable page flipping action from certain region so that kids can draw lines there?

Answer 1

Add tap UITapGestureRecognizer in viewDidLoad

/** add gesture recognizier */
UITapGestureRecognizer *singleTap =[[UITapGestureRecognizer alloc] initWithTarget:self action:nil];
singleTap.numberOfTouchesRequired = 1;
singleTap.cancelsTouchesInView    = NO;
singleTap.delegate                = self;
[_pageController.view addGestureRecognizer:singleTap];
[singleTap release];

catch UITapGestureRecognizer delegate method.

/** recognized tap on pageviewcontroller */
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:    (UITouch *)touch
{
    CGPoint touchPoint   = [touch locationInView:self.view];
    /** detect screen resolution */
    CGRect  screenBounds = [UIScreen mainScreen].bounds;

    if(touchPoint.x > (screenBounds.size.width *0.15) && touchPoint.x <     (screenBounds.size.width *0.75))
    {
        /** tap is on center */
        canScroll = NO;
    } else {
        /** tap is on corners */
        canScroll = YES;
    }

    /** detect the tap view */
    UIView *view = [self.view hitTest:touchPoint withEvent:nil];
    if([view isKindOfClass:[UIButton class]])
    {
        canScroll = NO;
    }

    return NO;
}

Override UIPageViewController datasource methods

/** move to previous page */
- (UIViewController *) pageViewController: (UIPageViewController *)pageViewController     viewControllerBeforeViewController:(UIViewController *)viewController
{
    if(canScroll)
    {
        return _prevPageViewController;
    }
    return  nil;
}

/** move to next page */
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
       viewControllerAfterViewController:(UIViewController *)viewController
{
    if(canScroll)
    { 
        return _nextPageViewController;
    }
    return nil;
}