使用UIPageViewController怎么实现左右滑动界面

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController

@end

#import "ViewController.h"
#import "SubPage1ViewController.h"
#import "SubPage2ViewController.h"
@interface ViewController ()<UIPageViewControllerDataSource,UIPageViewControllerDelegate>
@property NSArray *contentViewControllers; //ViewControllers
@property (nonatomic, strong) UIPageViewController *pageViewController;
@end

@implementation ViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  [self pageViewController];
}

- (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
}
#pragma mark
#pragma mark ----- UIPageViewControllerDataSource -----
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
  NSUInteger index = [self indexForViewController:viewController];
  if (index == 0) {
    index = [self.contentViewControllers count] - 1;
  } else {
    index--;
  }
  return [self viewControllerAtIndex:index];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
  NSUInteger index = [self indexForViewController:viewController];
  index++;
  if (index == [self.contentViewControllers count]) {
    index = 0;
  }
  return [self viewControllerAtIndex:index];
}
- (NSUInteger)indexForViewController:(UIViewController *)viewController
{
  return [self.contentViewControllers indexOfObject:viewController];
}

- (UIViewController *)viewControllerAtIndex:(NSUInteger)index
{
  if (index > [self.contentViewControllers count]) {
    return nil;
  }
  UIViewController *vc = [self.contentViewControllers objectAtIndex:index];
  return vc;
}
#pragma mark
#pragma mark ----- UIPageViewControllerDelegate -----
- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers
{


}
- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed
{
}
#pragma mark
#pragma mark Init
- (UIPageViewController *)pageViewController
{
  if(!_pageViewController)
  {
    NSDictionary *options =[NSDictionary dictionaryWithObject:[NSNumber numberWithInteger:UIPageViewControllerSpineLocationMin]
                              forKey: UIPageViewControllerOptionSpineLocationKey];
    _pageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll
                               navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal
                                      options:options];
    [[_pageViewController view] setFrame:[[self view] bounds]];
    _contentViewControllers = [NSMutableArray arrayWithObjects:[SubPage1ViewController new],[SubPage2ViewController new],nil];
    // 设置UIPageViewController的配置项
    [_pageViewController setViewControllers:[NSArray arrayWithObjects:_contentViewControllers[0], nil]
                   direction:UIPageViewControllerNavigationDirectionForward
                    animated:NO
                   completion:nil];
    _pageViewController.delegate = self;
    _pageViewController.dataSource = self;
    [self addChildViewController:self.pageViewController];
    [self.view addSubview:self.pageViewController.view];

  }
  return _pageViewController;

}