利用UICollectionView 實現輪播圖 :

<span style="font-size:24px;">//
//  ViewController.m
//  CollectionPhotosView
//
//  Created by 帝炎魔 on 16/5/30.
//  Copyright © 2016年 帝炎魔. All rights reserved.
//

/**
 *  UICollectionView  實現輪播圖的實現
    將定時器NSTimer 加入到mainrunloop中實現定時輪播
 *
    CollectionCell 和tableViewCell 用法不太一樣, CollectionCell 需要註冊, 告訴系統這種標識對應的cell是什麼型別的cell, 如果緩衝池中沒有, 自動建立這種型別的cell
 
 *
 */

#import "ViewController.h"
#import "News.h"
#import "YYCell.h"

#define kWidth [UIScreen mainScreen].bounds.size.width
#define kHeight [UIScreen mainScreen].bounds.size.height

#define MaxSections 100

@interface ViewController () <UICollectionViewDelegate, UICollectionViewDataSource>





@property (nonatomic, strong) UICollectionView *collectionView;

@property (nonatomic, strong) UIPageControl *pageControl;

@property (nonatomic, strong) NSMutableArray *news;

@property (nonatomic, strong) NSTimer *timer;


@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self.view addSubview:self.collectionView];
    
    [self.view addSubview:self.pageControl];
    
    // 註冊cell
    [self.collectionView registerClass:[YYCell class] forCellWithReuseIdentifier:@"Cell"];

    
    // 新增定時器 實現輪播功能呢
    [self addTimer];
    
    
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)addTimer
{
    _timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextPage) userInfo:NULL repeats:YES];
    
}

// 定時器的內容
- (void)nextPage
{
    // 獲取當前的 indexPath
    NSIndexPath *currentIndexPath = [[self.collectionView indexPathsForVisibleItems] lastObject];
    NSIndexPath *currentIndexPathSet = [NSIndexPath indexPathForItem:currentIndexPath.item inSection:MaxSections / 2];
    
    [self.collectionView scrollToItemAtIndexPath:currentIndexPathSet atScrollPosition:UICollectionViewScrollPositionLeft animated:NO];
    
    // 設定下一個滾動的item的indexPath
    NSInteger nextItem = currentIndexPathSet.item + 1;
    NSInteger nextSection = currentIndexPathSet.section;
    if (nextItem == self.news.count) {
        // 當item等於輪播圖的總個數的時候
        // item等於0, 分割槽加1
        // 未達到的時候永遠在50分割槽中
        nextItem = 0;
        nextSection ++;
    }
    // NSLog(@"----%ld---%ld", nextItem, nextSection);
    NSIndexPath *nextIndexPath = [NSIndexPath indexPathForItem:nextItem inSection:nextSection];
    [self.collectionView scrollToItemAtIndexPath:nextIndexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:YES];
    
}

#pragma mark ----ScrollView 代理方法
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    // 新增定時器
    [self addTimer];
}

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    // 移除定時器
    [self.timer invalidate];
    self.timer = nil;
}

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // 滾動時 動態設定 pageControl.currentPage
    int page = (int)(scrollView.contentOffset.x / scrollView.frame.size.width + 0.5) % self.news.count;
    self.pageControl.currentPage = page;
}

#pragma mark ---- 建立集合檢視

// 建立集合檢視
- (UICollectionView *)collectionView
{   
    if (!_collectionView) {
        // 建立UICollectionViewFlowLayout約束物件
        UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
        // 設定item的Size大小
        flowLayout.itemSize = CGSizeMake(kWidth, kHeight);
        // 設定uicollection 的 橫向滑動
        flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
        flowLayout.minimumLineSpacing = 0;
        
        _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, kWidth, kHeight) collectionViewLayout:flowLayout];
        
        // 設定代理
        _collectionView.delegate = self;
        _collectionView.dataSource = self;
        
        // 設定不展示滑動條
        _collectionView.showsHorizontalScrollIndicator = NO;
        // 設定整頁滑動
        _collectionView.pagingEnabled = YES;
        _collectionView.backgroundColor = [UIColor clearColor];

        
        // 設定當前collectionView 到哪個位置(indexPath row 0 section 取中間(50個))
        [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:MaxSections / 2] atScrollPosition:UICollectionViewScrollPositionLeft animated:YES];
        
       
        
    }
    return _collectionView;
    
}

- (UIPageControl *)pageControl
{
    if (!_pageControl) {
        UIPageControl *pageControl = [[UIPageControl alloc] init];
        pageControl.center = CGPointMake(kWidth / 2, kHeight - 100);
        pageControl.numberOfPages = _news.count;
        pageControl.bounds = CGRectMake(0, 0, 150, 40);
        pageControl.enabled = NO;
        pageControl.pageIndicatorTintColor = [UIColor blueColor];
        pageControl.currentPageIndicatorTintColor = [UIColor redColor];
        [self.view addSubview:pageControl];
        _pageControl = pageControl;
    }
    return _pageControl;
}

#pragma mark --- 資料來源
- (NSMutableArray *)news
{
    if (!_news) {
        NSString *path = [[NSBundle mainBundle] pathForResource:@"resource.plist" ofType:nil];
        NSArray *arr = [NSArray arrayWithContentsOfFile:path];
        _news = [NSMutableArray array];
        for (NSDictionary *dic in arr) {
            [_news addObject:[News newsWithDict:dic]];
        }
    }
    return _news;
}


#pragma mark --- 實現collectionView代理方法
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return MaxSections;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return self.news.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *string = @"Cell";
    YYCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:string forIndexPath:indexPath];
    if (!cell) {
        cell = [[YYCell alloc] init];
    }
    cell.news = self.news[indexPath.row];
    return cell;
}

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

@end
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