Mike V Mike V - 1 month ago 11
iOS Question

How do I make the bottom bar with dots of a UIPageViewController translucent?

I'm in the process of making a tutorial, and I'm trying to emulate the style of Path's tutorial like so:

http://www.appcoda.com/wp-content/uploads/2013/06/UIPageViewController-Tutorial-Screen.jpg
enter image description here

My issue is that if set the delegate method as so:

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
// The number of items reflected in the page indicator.
return 5;
}


Then I get this stupid black bar under the dots:

http://i.stack.imgur.com/pUEdh.png
enter image description here

Is there a way to make this bar translucent in a way thats similar to setting a UINavigationBar to translucent?

Answer

It is very easy to make it work. You just only have to make the pageviewcontroller taller, and place a PageControl into the XIB file. The trick is put the PageControl in the foreground (and all the other common controls) at the beginning, and update the content of the PageControl with the PageViewController. Here is the code:

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];

    self.pageController.dataSource = self;
    // We need to cover all the control by making the frame taller (+ 37)
    [[self.pageController view] setFrame:CGRectMake(0, 0, [[self view] bounds].size.width, [[self view] bounds].size.height + 37)];

    TutorialPageViewController *initialViewController = [self viewControllerAtIndex:0];

    NSArray *viewControllers = [NSArray arrayWithObject:initialViewController];

    [self.pageController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];

    [self addChildViewController:self.pageController];
    [[self view] addSubview:[self.pageController view]];
    [self.pageController didMoveToParentViewController:self];

    // Bring the common controls to the foreground (they were hidden since the frame is taller)
    [self.view bringSubviewToFront:self.pcDots];
    [self.view bringSubviewToFront:self.btnSkip];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController {

    NSUInteger index = [(TutorialPageViewController *)viewController index];

    [self.pcDots setCurrentPage:index];

    if (index == 0) {
        return nil;
    }

    index--;

    return [self viewControllerAtIndex:index];

}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {

    NSUInteger index = [(TutorialPageViewController *)viewController index];

    [self.pcDots setCurrentPage:index];

    index++;

    if (index == 3) {
        return nil;
    }


    return [self viewControllerAtIndex:index];

}

- (TutorialPageViewController *)viewControllerAtIndex:(NSUInteger)index {

    TutorialPageViewController *childViewController = [[TutorialPageViewController alloc] initWithNibName:@"TutorialPageViewController" bundle:nil];
    childViewController.index = index;

    return childViewController;

}

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    // The number of items reflected in the page indicator.
    NSInteger tutorialSteps = 3;
    [self.pcDots setNumberOfPages:tutorialSteps];

    return tutorialSteps;
}

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
    // The selected item reflected in the page indicator.
    return 0;
}