你真的了解UIScrollView吗？

NS_CLASS_AVAILABLE_IOS(2_0) @interface UIScrollView : UIView <NSCoding>

//表示UIScrollView滚动的位置(就是内容左上角与scrollView左上角的间距!!)
@property(nonatomic)         CGPoint                      contentOffset;                  // default CGPointZero
//表示UIScrollView内容的尺寸,滚动范围
@property(nonatomic)         CGSize                       contentSize;                    // default CGSizeZero
//在UIScrollView的四周增加额外的滚动区域,一般用来避免scrollView的内容被其他控件挡住
@property(nonatomic)         UIEdgeInsets                 contentInset;            
//委托       
@property(nullable,nonatomic,weak) id<UIScrollViewDelegate>        delegate;                       // default nil. weak reference
//设置当向一个方向滚动的时候,是否锁住向另外一个方向的滚动
@property(nonatomic,getter=isDirectionalLockEnabled) BOOL directionalLockEnabled;         // 默认值为 NO
//设置UIScrollView是否需要弹簧效果
@property(nonatomic)         BOOL                         bounces;                        // 默认值YES

//是否一直有弹簧效果: 使用范围 ContentSize.height < ScrollView.height 的情况下垂直方向默认情况下是没有弹簧效果的, 但是设置了AlwaysBounceVertical = YES的时候就会让在这种情况下仍然有弹簧效果
@property(nonatomic)         BOOL                         alwaysBounceVertical;           // 默认值 NO
@property(nonatomic)         BOOL                         alwaysBounceHorizontal;         // 默认值 NO

//控制控件是否整页翻动 默认值为NO
@property(nonatomic,getter=isPagingEnabled) BOOL          pagingEnabled;                 
//设置UIScrollView是否能滚动
@property(nonatomic,getter=isScrollEnabled) BOOL          scrollEnabled;                  //默认值 YES
//是否显示水平滚动条
@property(nonatomic)         BOOL                         showsHorizontalScrollIndicator; // 默认值YES
//是否显示垂直滚动条
@property(nonatomic)         BOOL                         showsVerticalScrollIndicator;   // 默认值YES

//设置滚动条到scrollView上左下右的边距,只有下和右有效
// 参数1: 设置x值无效
// 参数2: 设置y值无效
// 参数3: 设置下面的距离
// 参数4: 设置右边的距离
@property(nonatomic)         UIEdgeInsets                 scrollIndicatorInsets;  

// 设置滚动条的风格
// .Default  (默认)灰色
// .Black    黑色的滚动条
// .Whitr    白色的滚动条        
@property(nonatomic)         UIScrollViewIndicatorStyle   indicatorStyle;                 // 默认值 UIScrollViewIndicatorStyleDefault

// // 设置手指放开后的减速率
@property(nonatomic)         CGFloat                      decelerationRate NS_AVAILABLE_IOS(3_0);

//意思是需要动画 但是时间是苹果自己定义的第一个参数是你要滚动到的位置 第二个参数是是否要动画效果!
- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated; 

- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated;         // scroll so rect is just visible (nearest edges). nothing if rect completely visible

//短暂的显示一下状态条，当你将scrollView调整到最上面时，需要调用一下该方法
- (void)flashScrollIndicators;         

//只读，一旦用户开始触摸视图(也许还没有开始拖动)，该属性值为YES
@property(nonatomic,readonly,getter=isTracking)     BOOL tracking;        
//只读，当用户开始拖动（手指已经在屏幕上滑动一段距离了），该属性值为YES
@property(nonatomic,readonly,getter=isDragging)     BOOL dragging;        
//只读，当用户松开手指，但视图仍在滚动时，该值返回YES
@property(nonatomic,readonly,getter=isDecelerating) BOOL decelerating;    

//是否推迟触屏手势处理，默认值为YES。设置为YES的时候，系统在确定是否发生scroll事件之后，才会处理触屏手势，否则，则会立即调用touchesShouldBegin:withEvent:inContentView:方法
@property(nonatomic) BOOL delaysContentTouches;      

//假如你设置canCancelContentTouches为YES，那么当你在UIScrollView上面放置任何子视图的时候,当你在子视图上移动手指的时候，UIScrollView会给子视图发送touchCancel的消息。而如果该属性设置为NO，ScrollView本身不处理这个消息，全部交给子视图处理 默认值YES
@property(nonatomic) BOOL canCancelContentTouches;    

//如果返回值为 yes ， touch 事件传给子视图；如果为 no ， touch 事件不传给子视图
- (BOOL)touchesShouldBegin:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event inContentView:(UIView *)view;

- (BOOL)touchesShouldCancelInContentView:(UIView *)view;

// 设置最小的缩放倍数，默认值1.0
@property(nonatomic) CGFloat minimumZoomScale; 
// 设置最大缩放倍数，默认值1.0
@property(nonatomic) CGFloat maximumZoomScale; 

// 当前的缩放倍数
@property(nonatomic) CGFloat zoomScale NS_AVAILABLE_IOS(3_0);            // 默认值 1.0

//程序设置缩放大小
- (void)setZoomScale:(CGFloat)scale animated:(BOOL)animated NS_AVAILABLE_IOS(3_0);
//将内容视图缩放到指定的Rect中
- (void)zoomToRect:(CGRect)rect animated:(BOOL)animated NS_AVAILABLE_IOS(3_0);

//控制缩放的时候是否会反弹 默认值YES
@property(nonatomic) BOOL  bouncesZoom;          // default is YES. if set, user can go past min/max zoom while gesturing and the zoom will animate to the min/max value at gesture end

//只读，用户是否正在进行缩放手势
@property(nonatomic,readonly,getter=isZooming)       BOOL zooming;      
//只读，当缩放超过最大或者最小范围的时候，回弹到最大最小范围的过程中，该值返回YES。
@property(nonatomic,readonly,getter=isZoomBouncing)  BOOL zoomBouncing;  

//设置是否可以自动滚动到顶部(点击上面状态栏的时候),默认为true
@property(nonatomic) BOOL  scrollsToTop;   

//移动手势   只读
@property(nonatomic, readonly) UIPanGestureRecognizer *panGestureRecognizer NS_AVAILABLE_IOS(5_0);

// 缩放手势   只读
@property(nullable, nonatomic, readonly) UIPinchGestureRecognizer *pinchGestureRecognizer NS_AVAILABLE_IOS(5_0);

//当拖动发生时，键盘的消失模式，默认值是不消失UIScrollViewKeyboardDismissModeNone
@property(nonatomic) UIScrollViewKeyboardDismissMode keyboardDismissMode NS_AVAILABLE_IOS(7_0);

@end

1：没有设置contentSize
2：scrollEnabled = NO
3：没有接收到触摸事件:userInteractionEnabled = NO

self.automaticallyAdjustsScrollViewInsets = NO;

//---导入代理
@interface RootViewController ()<UIScrollViewDelegate>

@end

@implementation RootViewController

//viewDidLoad只执行一次
- (void)viewDidLoad {

    [super viewDidLoad];
    self.view.backgroundColor = [UIColor yellowColor];

    //-创建滚动视图  当我们需要显示的内容超过一屏时，就需要用到滚动视图
    UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];
    [scrollView setBackgroundColor:[UIColor orangeColor]];
    [self.view addSubview:scrollView];

    //-Key:设置滚动区域(内容区域的大小)
    scrollView.contentSize = CGSizeMake(CGRectGetWidth(self.view.frame) * 4, CGRectGetHeight(self.view.frame));
    //-为scrollview添加子视图
//    NSArray *colorArr = [NSArray arrayWithObjects:[UIColor cyanColor], [UIColor greenColor],  [UIColor redColor], [UIColor blueColor], nil];
    NSArray *imageArr = [NSArray arrayWithObjects:[UIImage imageNamed: @"woman1.jpg"], [UIImage imageNamed: @"woman2.jpg"], [UIImage imageNamed: @"woman3.jpg"], [UIImage imageNamed:@"woman4.jpg"],  nil];

    for (int i = 0; i < 4; i++) {

        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(CGRectGetWidth(self.view.frame)*i, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame))];
        label.text = [NSString stringWithFormat:@"这是志南的第%d夫人", i+1];
        label.font = [UIFont systemFontOfSize:30];
        label.textAlignment = NSTextAlignmentCenter;
//        label.backgroundColor = colorArr[i];//

        UIImageView *imageView = [[UIImageView alloc] initWithImage:imageArr[i]];
        imageView.frame = CGRectMake(CGRectGetWidth(self.view.frame)*i, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame));

        [scrollView addSubview:imageView];
        [scrollView addSubview:label];
    }

    //--设置分页效果
    scrollView.pagingEnabled = YES;
    //--设置横向滚动条是否显示 默认值为YES
    scrollView.showsHorizontalScrollIndicator = YES;
    //----------------------设置滚动条样式

    //--设置边界是否有反弹效果 默认值为YES
    scrollView.bounces = NO;

    //---设置代理
    scrollView.delegate = self;
}

#pragma mark -- 滚动视图的代理方法
//将要开始拖拽（手指触碰到屏幕，并且移动）
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    NSLog(@"---%s", __func__);
}

//已经开始滚动（只要scrollview是滚动状态就会调用此方法）
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{

    //------滚动视图上面的子视图可以移动，不是子视图改变自身的frame值，而是，通过改变更改滚动视图（也就是子视图的父视图）的bounds的origin（也就是x，y）来更改子视图在父视图（滚动视图）上显示的位置

    //scrollview的偏移量
    CGPoint offSet = scrollView.contentOffset;
    NSLog(@"----%s", __func__);
    //得到scrollView的bounds的x点，即水平方向偏移量
    NSLog(@"偏移量-----%f", offSet.x);
    float x = scrollView.bounds.origin.x;
    NSLog(@"bounds------%f", x);
    /*------【回顾】：bounds改变导致其子视图位置改变！！！
     改变子视图位置：scrollView滚动视图通过改变自身bounds，子view左上角坐标原点发生移动*/
}

//停止拖动（当手指（触摸对象）离开，正在滚动的视图减速）
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
    NSLog(@"--%s", __func__);
}

//视图真正静止（视图不动了）
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    NSLog(@"%s",__func__);
}


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

@end

- (void)viewDidLoad
{
    [super viewDidLoad];
// Do any additional setup after loading the view.

    // 设置背景色
    self.view.backgroundColor = [UIColor grayColor];

    // 添加UIScrollView
    self.userGuideScrollView = [[[UIScrollView alloc] initWithFrame:CGRectMake(0,0, self.view.frame.size.width, self.view.frame.size.height)] autorelease]; // 初始化位置和大小
    self.userGuideScrollView.contentSize = CGSizeMake(self.view.frame.size.width* 11, self.view.frame.size.height); // 设置存放的内容的大小
    _userGuideScrollView.pagingEnabled = YES; // 设置scrollView按一整页滑动
    _userGuideScrollView.delegate = self; // 设置代理为当前
    _userGuideScrollView.userInteractionEnabled = YES; // 设置可以与用户交互
    _userGuideScrollView.showsHorizontalScrollIndicator = YES; // 显示滑动时候横向的滚动条
    // 添加图片到UIScrollView中
    for (int i = 1; i <= 11; i++) {
        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImageimageNamed:[NSString stringWithFormat:@"image%d", i]]];
        imageView.frame = CGRectMake((i - 1) * self.view.frame.size.width, 0,self.view.frame.size.width, self.view.frame.size.height);
        [_userGuideScrollView addSubview:imageView];
        [imageView release], imageView = nil;
    }
    // 添加到当前的View
    [self.view addSubview:_userGuideScrollView];


    // 初始化UIPageController
    self.scrollPageControl = [[[UIPageControl alloc] init] autorelease];
    _scrollPageControl.frame = CGRectMake(0, self.view.frame.size.height - 60,self.view.frame.size.width, 30); // 设置位置
    _scrollPageControl.numberOfPages = 11; // 设置有多少个小点点
    _scrollPageControl.currentPage = 0; // 设置当前是哪个点点
    _scrollPageControl.pageIndicatorTintColor = [UIColor blueColor]; // 没有选中的点点的颜色
    _scrollPageControl.currentPageIndicatorTintColor = [UIColor yellowColor]; //当前点点的颜色
    [_scrollPageControl addTarget:self action:@selector(scrollPageControlAction:)forControlEvents:UIControlEventValueChanged]; // 设置监听事件
    _scrollPageControl.highlighted = YES;
    [self.view addSubview:_scrollPageControl];

}

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


#pragma mark - 实现---scrollPageControlAction:监听事件
- (void)scrollPageControlAction:(UIPageControl *) sender {
    //令UIScrollView做出相应的滑动显示
    CGSize viewSize = _userGuideScrollView.frame.size;
    CGRect rect = CGRectMake(sender.currentPage * viewSize.width, 0, viewSize.width, viewSize.height);
    [_userGuideScrollView scrollRectToVisible:rect animated:YES];
}


#pragma mark - 重写----scrollViewDelegate中的代理方法 实现滑动
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    // 计算偏移量
    int index = abs(scrollView.contentOffset.x / scrollView.frame.size.width);
    // 根据偏移量来设置pageControl
    _scrollPageControl.currentPage = index;
}


#pragma mark - 重写----dealloc方法
- (void)dealloc {
    // 释放属性的内存
    _scrollPageControl = nil;
    _userGuideScrollView = nil;
}

@protocol UIScrollViewDelegate<NSObject>

@optional

//只要滚动了就会触发 
- (void)scrollViewDidScroll:(UIScrollView *)scrollView;                                               
//缩放过程中不断调用该方法
- (void)scrollViewDidZoom:(UIScrollView *)scrollView NS_AVAILABLE_IOS(3_2); 

//开始拖拽视图 调用该方法
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView;
//将要完成拖拽调用该方法
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset NS_AVAILABLE_IOS(5_0);

//完成拖拽调用该方法
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate;

//将开始降速时调用该方法
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView;  
//减速停止了时执行，手触摸时执行 
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView;      

//滚动动画停止时执行,代码改变时出发,也就是setContentOffset改变时 
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView;

//设置放大缩小的视图，要是uiscrollview的subview  
- (nullable UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView;   
 
// 即将开始缩放时调用
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view NS_AVAILABLE_IOS(3_2); 

//完成放大缩小时调用
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(nullable UIView *)view atScale:(CGFloat)scale;

//如果你不是完全滚动到滚轴视图的顶部，你可以轻点状态栏，那个可视的滚轴视图会一直滚动到顶部，那是默认行为，你可以通过该方法返回NO来关闭它  
- (BOOL)scrollViewShouldScrollToTop:(UIScrollView *)scrollView;  

//已滚动顶部调用此方法
- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView;     

@end

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat imageH = self.imageView.frame.size.height;
    CGFloat offsetY = scrollView.contentOffset.y;
    // 该判断是实现scrollView内部的子控件悬停效果
    if (offsetY >= imageH) {
        // 将红色控件添加到控制器的view中，设置Y值为0
        CGRect redF = self.redView.frame;
        redF.origin.y = 0;
        self.redView.frame = redF;
        [self.view addSubview:self.redView];
    }else{
        // 将红色控件添加到scrollView中，设置Y值为图片的高度
        CGRect redF = self.redView.frame;
        redF.origin.y = 140;
        self.redView.frame = redF;
        [self.scrollView addSubview:self.redView];
    }

    // 实现下拉放大顶部图片效果
    CGFloat scale = 1 - (offsetY / 70);
    scale = (scale >= 1) ? scale : 1;
    self.imageView.transform = CGAffineTransformMakeScale(scale, scale);
}

//宏定义屏幕的宽和高
#define ScreenWight [UIScreen mainScreen].bounds.size.width
#define ScreenHeight [UIScreen mainScreen].bounds.size.height

@interface ViewController ()<UIScrollViewDelegate>//签滚动视图协议,为了实现协议方法
/** 滚动视图属性 */
@property(nonatomic, retain)UIScrollView *scrollView;
/** 分页控件属性 */
@property(nonatomic, retain)UIPageControl *pageControl;
/** 标记属性 */
@property(nonatomic, assign)BOOL flag;
@end

- (void)loadView
{
    [super loadView];
    self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];
    //设置容量
    self.scrollView.contentSize = CGSizeMake(8 * ScreenWight, ScreenHeight);
    //添加滚动视图
    [self.view addSubview:_scrollView];
    //设置整页翻动
    self.scrollView.pagingEnabled = YES;
    //设置偏移量
    self.scrollView.contentOffset = CGPointMake(ScreenWight, 0);
    //设置代理人
    self.scrollView.delegate = self;
    for (NSInteger i = 1; i < 7; i++) {
        //创建小的滚动视图
        /**
          为什么要创建小的滚动视图?
          因为在进行缩放之后发现,之前的滚动效果发生了变化,
          原因在于当我们进行缩放的时候,协议方法不但会改变视图的尺存,同样也可以改变scrollView的contenSize属性。
          解决方法:大的scrollView上先铺设小的scrollView ,然后把imageView放到小的scrollView上
          大的scrollView主要承担水平或垂直滚动,小的scrollView承担缩放的功能,
          并且每个都设置好缩放比例,这样再进行缩放,只会改变小scrollView的contenSize, 不会改变scrollView的contentSize。
         */
        UIScrollView *tempScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(ScreenWight * i, 0, ScreenWight, ScreenHeight)];
        tempScrollView.contentSize = CGSizeMake(ScreenWight, ScreenHeight);
        //隐藏底部和右侧滚动条
        tempScrollView.showsVerticalScrollIndicator = NO;
        tempScrollView.showsHorizontalScrollIndicator = NO;
        //设置缩放的比例
        tempScrollView.minimumZoomScale = 0.5f;
        tempScrollView.maximumZoomScale = 3.0f;
        //小滚动视图设置代理,为的是实现缩放的代理方法
        tempScrollView.delegate = self;
        [self.scrollView addSubview:tempScrollView];

        //循环往小滚动视图添加图片
        UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, ScreenWight, ScreenHeight)];
        NSString *imageName = [NSString stringWithFormat:@"%ld.JPG", i];
        imageView.image = [UIImage imageNamed:imageName];
        [tempScrollView addSubview:imageView];
       

        //设置轻拍手势
        //首先打开imageView的用户交互,默认是关闭
        imageView.userInteractionEnabled = YES;
        UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(didTapImageView:)];
        tapGesture.numberOfTapsRequired = 2;
        [imageView addGestureRecognizer:tapGesture];
    }

    //在最前面加上最后一张图,障眼法,给人一种感觉从第一页循环回最后一页
    //在此刻改变滚动视图的偏移量
    UIScrollView *frontScroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, ScreenWight, ScreenHeight)];
    frontScroll.contentSize = CGSizeMake(ScreenWight, ScreenHeight);
    [self.scrollView addSubview:frontScroll];
    UIImageView *frontImageView = [[UIImageView alloc] initWithFrame:self.view.frame];
    frontImageView.image = [UIImage imageNamed:@"6.JPG"];
    [frontScroll addSubview:frontImageView];
    //在最后面加上第一张图
    UIScrollView *lastScroll = [[UIScrollView alloc] initWithFrame:CGRectMake(7 * ScreenWight, 0, ScreenWight, ScreenHeight)];
    lastScroll.contentSize = CGSizeMake(ScreenWight, ScreenHeight);
    [self.scrollView addSubview:lastScroll];
    UIImageView *lastImageView = [[UIImageView alloc] initWithFrame:self.view.frame];
    lastImageView.image = [UIImage imageNamed:@"1.JPG"];
    [lastScroll addSubview:lastImageView];

    //分页控件
    self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(100, 600, 175, 30)];
    self.pageControl.numberOfPages = 6;
    [self.view addSubview:_pageControl];

    [self.pageControl addTarget:self action:@selector(didClickedPageControl:) forControlEvents:UIControlEventValueChanged];
}

#pragma mark 自定义方法,获取放大后显示的矩形区域
- (CGRect)zoomRectByScale:(CGFloat)scale Center:(CGPoint)center
{
    CGRect zoomRect;
    //求出新的长和宽
    zoomRect.size.width = ScreenWight / scale;
    zoomRect.size.height = ScreenHeight / scale;

    //找到新的原点
    zoomRect.origin.x = center.x * (1 - 1/scale);
    zoomRect.origin.y = center.y * (1 - 1/scale);

    return zoomRect;
}

#pragma mark 轻拍方法
- (void)didTapImageView:(UITapGestureRecognizer *)tap
{
    //这个是要获取当前点击的小滚动视图,而小滚动视图我们没有设置属性,无法在这儿获取
    //当前点击视图的父视图,其实就是当前点击的小滚动视图,就通过这种方法获取滚动视图对象
    UIScrollView *scroll = (UIScrollView *)tap.view.superview;
    if (_flag == NO) {
        CGRect newRect = [self zoomRectByScale:3.0 Center:[tap locationInView:tap.view]];
        //zoomToRect方法是UIScrollVie对象的方法,将图片相对放大
        [scroll zoomToRect:newRect animated:YES];
        _flag = YES;
    }else {
        [scroll setZoomScale:1 animated:YES];
        _flag = NO;
    }
}

#pragma mark 缩放的代理方法
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    //这个代理方法就是要返回一个view跟着scrollView缩放,
    //这个时候就会把scrollView的contentSize设置为imageView的大小
    //同时只能有一个view跟着scrollView缩放
    return scrollView.subviews.firstObject;
}

#pragma mark 滚动结束的代理方法
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    //滚动停止后,将每个小滚动视图比例还原
    for (UIScrollView *tempScroll in scrollView.subviews) {
        if ([tempScroll isKindOfClass:[UIScrollView class]]) {
            tempScroll.zoomScale = 1.0;
        }
    }
    //判断偏移量,并改变当前偏移量,实现循环播放功能
    if (scrollView.contentOffset.x == 0) {
        self.scrollView.contentOffset = CGPointMake(6 * ScreenWight, 0);
    }
    if (scrollView.contentOffset.x == ScreenWight * 7) {
        self.scrollView.contentOffset = CGPointMake(ScreenWight, 0);
    }
    //获取当前的页数,即滚动视图控制分页控件
    NSInteger pageNum = (long)(scrollView.contentOffset.x -  ScreenWight) / ScreenWight;
    //改变当前分页控件的显示页数
    self.pageControl.currentPage = pageNum;
}

#pragma mark 分页控件的触发方法
- (void)didClickedPageControl:(UIPageControl *)pageControl
{
    //根据当前点的下标,修改滚动视图应该显示的图片,即分页控件控制滚动视图
    CGPoint newPoint = CGPointMake((pageControl.currentPage + 1) * ScreenWight , 0);
    //修改滚动视图偏移量
    [self.scrollView setContentOffset:newPoint animated:YES];
}