UIPageViewController可用于管理多個平行關(guān)系的viewCOntroller，提供頁面滑動和很炫的翻頁效果，可用于引導(dǎo)頁切換。
配置屬性
UIPageViewController可以配置多個屬性進行展示，
| 名稱 | 含義 | 值 |
|---|---|---|
| navigationOrientation | 導(dǎo)航的方向：水平or垂直 | UIPageViewControllerNavigationOrientationHorizontal、UIPageViewControllerNavigationOrientationVertical |
| transitionStyle | 翻頁的過渡樣式：類似書頁翻卷或者Scroll滑動 | UIPageViewControllerTransitionStylePageCurl、UIPageViewControllerTransitionStyleScroll |
| spineLocation | 書脊位置，只有書頁翻卷效果時有效； | UIPageViewControllerSpineLocationNone：無書脊、UIPageViewControllerSpineLocationMin：根據(jù)導(dǎo)航方向，位于屏幕左側(cè)或頂部、UIPageViewControllerSpineLocationMid：位于屏幕中部，同時顯示兩個頁面、UIPageViewControllerSpineLocationMax：根據(jù)導(dǎo)航方向，位于屏幕右側(cè)或底部 |
| doubleSided | 屏幕是否顯示兩個頁面，當spineLocation為mid時，其值需設(shè)為Yes | 默認為no |
初始化
a) UIPageViewController初始化方法
- (instancetype)initWithTransitionStyle:(UIPageViewControllerTransitionStyle)style
navigationOrientation:(UIPageViewControllerNavigationOrientation)navigationOrientation
options:(NSDictionary<NSString *,id> *)options
參數(shù)style對應(yīng)上述文中transitionStyle，navigationOrientation對應(yīng)導(dǎo)航方向，options是可選的,但只可以是UIPageViewControllerOptionSpineLocationKey和UIPageViewControllerOptionInterPageSpacingKey組成的字典.
- UIPageViewControllerOptionSpineLocationKey：定義書脊位置，只有其transitionStyle選為UIPageViewControllerTransitionStylePageCurl才有效
- UIPageViewControllerOptionInterPageSpacingKey：定義兩個頁面的間距，只有其transitionStyle選為UIPageViewControllerTransitionStyleScroll才有效
b) 設(shè)置UIPageViewController初始顯示的viewController
- (void)setViewControllers:(NSArray<UIViewController *> *)viewControllers
direction:(UIPageViewControllerNavigationDirection)direction
animated:(BOOL)animated
completion:(void (^)(BOOL finished))completion
參數(shù)direction值分為UIPageViewControllerNavigationDirectionForward（水平導(dǎo)航時為從左向右，垂直方向時為從上到下）、
UIPageViewControllerNavigationDirectionReverse（水平導(dǎo)航時為從右向左，垂直方向時為從下到上）
DataSource
UIPageViewControllerDataSource提供了四個方法，兩個是@required，兩個是@optional
@required
//返回前一個頁面;如果返回為nil,則會認為當前頁面不可以向前滾動或翻頁
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
viewControllerBeforeViewController:(UIViewController *)viewController
//返回后一個頁面;如果返回為nil,則會認為當前頁面不可以向后滾動或翻頁
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
viewControllerAfterViewController:(UIViewController *)viewController
@optional
//返回頁面總數(shù)
- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController
//返回默認展示的頁面index
- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController
需要注意的是@optional中的方法是和頁面指示器（Page Indicator）相對應(yīng)的，實現(xiàn)了這兩個方法，才可以顯示Page Indicator；同時Page Indicator是在scroll過渡效果下顯示。
Delegate
UIPageViewControllerDelegate定義了五個方法
//開始滾動或者翻頁時執(zhí)行
- (void)pageViewController:(UIPageViewController *)pageViewController
willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers
//結(jié)束滾動或者翻頁時執(zhí)行
- (void)pageViewController:(UIPageViewController *)pageViewController
didFinishAnimating:(BOOL)finished
previousViewControllers:(NSArray<UIViewController *> *)previousViewControllers
transitionCompleted:(BOOL)completed
//在書頁翻卷效果和旋轉(zhuǎn)屏幕時執(zhí)行，可以根據(jù)屏幕旋轉(zhuǎn)方向設(shè)置書脊位置和初始化首頁
- (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewController
spineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation
//支持的屏幕類型
- (UIInterfaceOrientationMask)pageViewControllerSupportedInterfaceOrientations:(UIPageViewController *)pageViewController
- (UIInterfaceOrientation)pageViewControllerPreferredInterfaceOrientationForPresentation:(UIPageViewController *)pageViewController
實現(xiàn)效果
類似于scroll滾動效果如下圖：
類似于書卷翻頁效果如下圖：
具體實現(xiàn)可以移步代碼
可以利用UIPageControl修改page indicator，具體如下
UIPageControl *pageControl = [UIPageControl appearance];
pageControl.pageIndicatorTintColor = [UIColor lightGrayColor];
pageControl.currentPageIndicatorTintColor = [UIColor blackColor];
pageControl.backgroundColor = [UIColor whiteColor];
