UIPageViewController教程

UIPageViewController简介

UIPageViewController是iOS 5.0之后提供的一个分页控件可以实现图片轮播效果和翻书效果.使用起来也很简单方便.

UIPageViewController使用

初始化

进入系统API你可以找到iOS SDK提供的初始化方法

- (instancetype)initWithTransitionStyle:(UIPageViewControllerTransitionStyle)stylenavigationOrientation:(UIPageViewControllerNavigationOrientation)navigationOrientationoptions:(nullable NSDictionary<NSString *, id> *)options NS_DESIGNATED_INITIALIZER;
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初始化方法提供三个参数:

style: 这个参数是UIPageViewController翻页的过渡样式,系统提供了两种过度样式,分别是

UIPageViewControllerTransitionStylePageCurl : 卷曲样式类似翻书效果
UIPageViewControllerTransitionStyleScroll : UIScrollView滚动效果

navigationOrientation: 这个参数是UIPageViewController导航方向,系统提供了两种方式,分别是

UIPageViewControllerNavigationOrientationHorizontal : 水平导航方式
UIPageViewControllerNavigationOrientationVertical : 垂直导航方式

options: 这个参数是可选的,传入的是对UIPageViewController的一些配置组成的字典,不过这个参数只能以UIPageViewControllerOptionSpineLocationKey和UIPageViewControllerOptionInterPageSpacingKey这两个key组成的字典.

UIPageViewControllerOptionSpineLocationKey 这个key只有在style是翻书效果UIPageViewControllerTransitionStylePageCurl的时候才有作用, 它定义的是书脊的位置,值对应着UIPageViewControllerSpineLocation这个枚举项,不要定义错了哦.
UIPageViewControllerOptionInterPageSpacingKey这个key只有在style是UIScrollView滚动效果UIPageViewControllerTransitionStyleScroll的时候才有作用, 它定义的是两个页面之间的间距(默认间距是0).

除了初始化方法系统还提供了一个属性

@property (nonatomic, getter=isDoubleSided) BOOL doubleSided; // Default is 'NO'.
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这个属性默认为NO,如果我们当前屏幕仅展示一个页面那么不用设置这个属性,如果设置了UIPageViewControllerSpineLocationMid这个选项,效果是翻开的书这样屏幕展示的就是两个页面,这个属性就必须设置为YES了.

此外还有一个重要方法:

- (void)setViewControllers:(nullable NSArray<UIViewController *> *)viewControllersdirection:(UIPageViewControllerNavigationDirection)directionanimated:(BOOL)animatedcompletion:(void (^ __nullable)(BOOL finished))completion;复制代码

这个方法是设置UIPageViewController初始显示的页面,如果doubleSided设为YES了,那么viewControllers这个参数至少包含两个页面.

数据源和代理

UIPageViewController类似UITableViewController机制可以设置数据源和代理.

数据源 `<UIPageViewControllerDataSource>`

iOS SDK提供了四个数据源方法,其中两个为@required,另外两个是@optional.

@required

- (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewControllerviewControllerBeforeViewController:(UIViewController *)viewController;
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这个方法是返回前一个页面,如果返回为nil,那么UIPageViewController就会认为当前页面是第一个页面不可以向前滚动或翻页

- (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewControllerviewControllerAfterViewController:(UIViewController *)viewController;
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这个方法是下一个页面,如果返回为nil,那么UIPageViewController就会认为当前页面是最后一个页面不可以向后滚动或翻页

代理 `<UIPageViewControllerDelegate>`

iOS SDK提供了五个代理方法:

// Sent when a gesture-initiated transition begins.
- (void)pageViewController:(UIPageViewController *)pageViewController
willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers NS_AVAILABLE_IOS(6_0);
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这个方法是UIPageViewController开始滚动或翻页的时候触发

// Sent when a gesture-initiated transition ends. The 'finished' parameter indicates whether the animation finished, while the 'completed' parameter indicates whether the transition completed or bailed out (if the user let go early).
- (void)pageViewController:(UIPageViewController *)pageViewControllerdidFinishAnimating:(BOOL)finishedpreviousViewControllers:(NSArray<UIViewController *> *)previousViewControllerstransitionCompleted:(BOOL)completed;
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这个方法是在UIPageViewController结束滚动或翻页的时候触发

// Delegate may specify a different spine location for after the interface orientation change. Only sent for transition style 'UIPageViewControllerTransitionStylePageCurl'.
// Delegate may set new view controllers or update double-sided state within this method's implementation as well.
- (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewControllerspineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation __TVOS_PROHIBITED;
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这个方法是在style是UIPageViewControllerTransitionStylePageCurl 并且横竖屏状态变化的时候触发,我们可以重新设置书脊的位置,比如如果屏幕是竖屏状态的时候我们就设置书脊位置是UIPageViewControllerSpineLocationMin或UIPageViewControllerSpineLocationMax, 如果屏幕是横屏状态的时候我们可以设置书脊位置是UIPageViewControllerSpineLocationMid

- (UIInterfaceOrientationMask)pageViewControllerSupportedInterfaceOrientations:(UIPageViewController *)pageViewController NS_AVAILABLE_IOS(7_0) __TVOS_PROHIBITED;
- (UIInterfaceOrientation)pageViewControllerPreferredInterfaceOrientationForPresentation:(UIPageViewController *)pageViewController NS_AVAILABLE_IOS(7_0) __TVOS_PROHIBITED;
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这两个方法设置了UIPageViewController支持的屏幕类型

实现效果

翻书效果

直接上代码和效果

ViewController的.m代码如下:

@interface ViewController () <UIPageViewControllerDelegate, UIPageViewControllerDataSource>@property (nonatomic, strong) UIPageViewController *pageViewController;
@property (nonatomic, strong) NSArray *pageContentArray;@end@implementation ViewController#pragma mark - Lazy Load- (NSArray *)pageContentArray {if (!_pageContentArray) {NSMutableArray *arrayM = [[NSMutableArray alloc] init];for (int i = 1; i < 10; i++) {NSString *contentString = [[NSString alloc] initWithFormat:@"This is the page %d of content displayed using UIPageViewController", i];[arrayM addObject:contentString];}_pageContentArray = [[NSArray alloc] initWithArray:arrayM];}return _pageContentArray;
}#pragma mark - Life Cycle- (void)viewDidLoad {[super viewDidLoad];// 设置UIPageViewController的配置项
//    NSDictionary *options = @{UIPageViewControllerOptionInterPageSpacingKey : @(20)};NSDictionary *options = @{UIPageViewControllerOptionSpineLocationKey : @(UIPageViewControllerSpineLocationMin)};// 根据给定的属性实例化UIPageViewController_pageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurlnavigationOrientation:UIPageViewControllerNavigationOrientationHorizontaloptions:options];// 设置UIPageViewController代理和数据源_pageViewController.delegate = self;_pageViewController.dataSource = self;// 设置UIPageViewController初始化数据, 将数据放在NSArray里面// 如果 options 设置了 UIPageViewControllerSpineLocationMid,注意viewControllers至少包含两个数据,且 doubleSided = YESContentViewController *initialViewController = [self viewControllerAtIndex:0];// 得到第一页NSArray *viewControllers = [NSArray arrayWithObject:initialViewController];[_pageViewController setViewControllers:viewControllersdirection:UIPageViewControllerNavigationDirectionReverseanimated:NOcompletion:nil];// 设置UIPageViewController 尺寸_pageViewController.view.frame = self.view.bounds;// 在页面上，显示UIPageViewController对象的View[self addChildViewController:_pageViewController];[self.view addSubview:_pageViewController.view];}#pragma mark - UIPageViewControllerDataSource And UIPageViewControllerDelegate#pragma mark 返回上一个ViewController对象- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController {NSUInteger index = [self indexOfViewController:(ContentViewController *)viewController];if ((index == 0) || (index == NSNotFound)) {return nil;}index--;// 返回的ViewController，将被添加到相应的UIPageViewController对象上。// UIPageViewController对象会根据UIPageViewControllerDataSource协议方法,自动来维护次序// 不用我们去操心每个ViewController的顺序问题return [self viewControllerAtIndex:index];}#pragma mark 返回下一个ViewController对象- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {NSUInteger index = [self indexOfViewController:(ContentViewController *)viewController];if (index == NSNotFound) {return nil;}index++;if (index == [self.pageContentArray count]) {return nil;}return [self viewControllerAtIndex:index];}#pragma mark - 根据index得到对应的UIViewController- (ContentViewController *)viewControllerAtIndex:(NSUInteger)index {if (([self.pageContentArray count] == 0) || (index >= [self.pageContentArray count])) {return nil;}// 创建一个新的控制器类，并且分配给相应的数据ContentViewController *contentVC = [[ContentViewController alloc] init];contentVC.content = [self.pageContentArray objectAtIndex:index];return contentVC;
}#pragma mark - 数组元素值，得到下标值- (NSUInteger)indexOfViewController:(ContentViewController *)viewController {return [self.pageContentArray indexOfObject:viewController.content];
}@end
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ContentViewController的.h代码

@interface ContentViewController : UIViewController@property (nonatomic, copy) NSString *content;@end
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ContentViewController的.m代码

#define kRandomColor ([UIColor colorWithRed:arc4random_uniform(256)/255.0 green:arc4random_uniform(256)/255.0 blue:arc4random_uniform(256)/255.0 alpha:1.0f])@interface ContentViewController ()@property (nonatomic, strong) UILabel *contentLabel;@end@implementation ContentViewController- (void)viewDidLoad{[super viewDidLoad];self.view.backgroundColor = kRandomColor;_contentLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 50, self.view.bounds.size.width, 100)];_contentLabel.numberOfLines = 0;_contentLabel.backgroundColor = kRandomColor;[self.view addSubview:_contentLabel];
}- (void) viewWillAppear:(BOOL)paramAnimated{[super viewWillAppear:paramAnimated];_contentLabel.text = _content;
}@end
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滚动效果

关于滚动效果只需将初始化配置修改一下即可:

    // 设置UIPageViewController的配置项NSDictionary *options = @{UIPageViewControllerOptionInterPageSpacingKey : @(20)};
//    NSDictionary *options = @{UIPageViewControllerOptionSpineLocationKey : @(UIPageViewControllerSpineLocationMin)};// 根据给定的属性实例化UIPageViewController_pageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScrollnavigationOrientation:UIPageViewControllerNavigationOrientationHorizontaloptions:options];
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UIPageViewController 总结

关于UIPageViewController的使用就介绍这么多,关键点在于UIPageViewController的配置项的设置以及数据源的控制. 希望这篇文章会对你有所帮助 Demo地址 https://github.com/Herb-Sun/UIPageViewControllerDemo

转载于:https://juejin.im/post/5aa53fb9f265da239376b346