#import "ViewController.h"/// 當前controller#import "MyViewController.h" /// 復用的controller 適用于每個控制器布局相同的情況下，，布局不同就創建不同的controller添加進來#import "TitleCollectionViewCell.h"/// 標題欄使用的collectionviewcell@interface ViewController ()<UIPageViewControllerDelegate,UIPageViewControllerDataSource,UICollectionViewDelegate,UICollectionViewDataSource>{ //// 記錄當前頁 當前標題位置 NSInteger ld_currentIndex;}@property (nonatomic, strong) UIPageViewController *pageViewController;@property (nonatomic, strong) NSMutableArray *controllersArr;/// 控制器數組@property (nonatomic, strong) NSMutableArray *titleArray; /// 標題數組@property (nonatomic, strong) UICollectionView *titleCollectionView; /// 標題collectionview@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad]; self.view.backgroundColor = [UIColor whiteColor]; self.navigationController.navigationBar.translucent = NO; self.controllersArr = [NSMutableArray array]; self.titleArray = [NSMutableArray array]; //// 如果controller布局相同則循環創建MyViewController 添加進數組，，如果controller 布局不同 那就創建多個不同controller依次添加數組 for (int i = 0; i < 10; i++) {  MyViewController *con = [[MyViewController alloc]init];  [self.controllersArr addObject:con];  NSString *str = [NSString stringWithFormat:@"第 %d 頁", i+1];  con.titlestring = str;  [self.titleArray addObject:str]; } [self createCollectionView]; [self createPageViewController]; [self setTheFirstPage];}/// 創建標題collectionview- (void)createCollectionView{ UICollectionViewFlowLayout *lay = [[UICollectionViewFlowLayout alloc] init]; lay.itemSize = CGSizeMake(60, 30); lay.minimumLineSpacing = 0; lay.minimumInteritemSpacing = 0; lay.scrollDirection = UICollectionViewScrollDirectionHorizontal; self.titleCollectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 34, 375, 30) collectionViewLayout:lay]; self.titleCollectionView.showsHorizontalScrollIndicator = NO; self.titleCollectionView.backgroundColor = [UIColor whiteColor]; self.titleCollectionView.delegate = self; self.titleCollectionView.dataSource = self; [self.titleCollectionView registerClass:[TitleCollectionViewCell class] forCellWithReuseIdentifier:@"titleReuse"]; [self.navigationController.view addSubview:self.titleCollectionView];}//// 標題collectionview的協議方法- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{ return self.titleArray.count;}- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath { TitleCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"titleReuse" forIndexPath:indexPath]; cell.titleLabel.text = self.titleArray[indexPath.row]; if (indexPath.row == ld_currentIndex) {  cell.titleLabel.textColor = [UIColor orangeColor]; }else{  cell.titleLabel.textColor = [UIColor blackColor]; } return cell;}//// 點擊標題左右切換視圖控制器------------再也不用看到好幾個中間頁面從屏幕快速閃過了------- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{ UIViewController *vc = [self.controllersArr objectAtIndex:indexPath.row]; if (indexPath.row > ld_currentIndex) {  [self.pageViewController setViewControllers:@[vc] direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:^(BOOL finished) {  }]; } else {  [self.pageViewController setViewControllers:@[vc] direction:UIPageViewControllerNavigationDirectionReverse animated:YES completion:^(BOOL finished) {  }]; } ld_currentIndex = indexPath.row; NSIndexPath *path = [NSIndexPath indexPathForRow:ld_currentIndex inSection:0]; [self.titleCollectionView scrollToItemAtIndexPath:path atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES]; [self.titleCollectionView reloadData];}/// 創建pageViewController- (void)createPageViewController { NSDictionary *option = [NSDictionary dictionaryWithObject:[NSNumber numberWithInteger:0] forKey:UIPageViewControllerOptionInterPageSpacingKey]; _pageViewController = [[UIPageViewController alloc]initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:option]; _pageViewController.delegate = self; _pageViewController.dataSource = self; [self addChildViewController:_pageViewController]; [self.view addSubview:_pageViewController.view];}/// 展示上一頁- (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController { NSInteger index = [self.controllersArr indexOfObject:viewController]; if (index == 0 || (index == NSNotFound)) {  return nil; } index--; return [self.controllersArr objectAtIndex:index];}/// 展示下一頁- (nullable UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController { NSInteger index = [self.controllersArr indexOfObject:viewController]; if (index == self.controllersArr.count - 1 || (index == NSNotFound)) {  return nil; } index++; return [self.controllersArr objectAtIndex:index];}/// 將要滑動切換的時候- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers { UIViewController *nextVC = [pendingViewControllers firstObject]; NSInteger index = [self.controllersArr indexOfObject:nextVC]; ld_currentIndex = index;}/// 滑動結束后- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray<UIViewController *> *)previousViewControllers transitionCompleted:(BOOL)completed { if (completed) {  NSIndexPath *path = [NSIndexPath indexPathForRow:ld_currentIndex inSection:0];  [self.titleCollectionView scrollToItemAtIndexPath:path atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];  [self.titleCollectionView reloadData];  NSLog(@">>>>>>>>> %ld", (long)ld_currentIndex); } }/// 設置默認顯示的是哪個頁面（controller）- (void)setTheFirstPage{ UIViewController *vc = [self.controllersArr objectAtIndex:ld_currentIndex]; [self.pageViewController setViewControllers:@[vc] direction:UIPageViewControllerNavigationDirectionReverse animated:YES completion:nil];}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}TitleCollectionViewCell@implementation TitleCollectionViewCell- (instancetype)initWithFrame:(CGRect)frame{ self = [super initWithFrame:frame]; if (self) {  [self createView]; } return self;}- (void)createView{ self.titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.contentView.frame.size.width, self.contentView.frame.size.height)]; [self.contentView addSubview:self.titleLabel]; self.titleLabel.font = [UIFont systemFontOfSize:14];}@end