UIScorlView 循环滚动

- (void) createAdScrollView

{

    _view = [[UIView alloc] initWithFrame:CGRectMake(, , WIDTH, )];

    [self.view addSubview:_view];

    _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(, , WIDTH, )];

    _scrollView.delegate = self;

    // 设置scrollView的contentSize

    _scrollView.contentSize = CGSizeMake(WIDTH*(self.scrollViewDataArray.count+), );

    _scrollView.pagingEnabled = YES;

    _scrollView.delegate = self;

    // 注意这里不需要add，因为在headerView时直接return _scrollView；

     [_view addSubview:_scrollView];

    for (int i=; i<self.scrollViewDataArray.count+; i++) {

        int y = i;

        if (y == self.scrollViewDataArray.count) {

            y = ;

        }

        UIButton *button = [ZCControl createButtonWithFrame:CGRectMake(WIDTH*i, , WIDTH, ) title:nil imageName:nil bgImageName:nil target:self method:@selector(buttonClick:)];

//        [button sd_setBackgroundImageWithURL:[NSURL URLWithString:self.scrollViewDataArray[y][@"image_path"]] forState:UIControlStateNormal]; placeholderImage:[UIImage imageNamed:@"recommend_Face"];

        button.tag = +i;

        [_scrollView addSubview:button];

    }

    // 添加定时器

    [NSTimer scheduledTimerWithTimeInterval: target:self selector:@selector(timerClick) userInfo:nil repeats:YES];

    // 添加小白点

    pageController = [[UIPageControl alloc]initWithFrame:CGRectMake(, , , )];

    pageController.numberOfPages = self.scrollViewDataArray.count;

    // 白色看不清设置成其他颜色

    pageController.pageIndicatorTintColor = [UIColor grayColor];

    // pageController虽然是和scrollView并用的，但是并不加载在sc

    [_view addSubview:pageController];

    // kvo观察者模式,负责观察某一个对象其中某一个值的变化，如果有新值变化就通知你。需要注意的是，观察者模式需要手动销毁，当前界面销毁并不代表观察者模式也销毁了

    // sc观察的对象，self为响应的对象，path为观察sc其中的一个属性，使用字符串来表示这个属性，要求与属性名保持一致。options为观察值变化为有新的变化的时候，通知我。context上下文

    [_scrollView addObserver:self forKeyPath:@"contentOffset" options:NSKeyValueObservingOptionNew context:nil];

}

- (void)timerClick{

    // 首先判断_scrollView当前的偏移

    CGPoint point = _scrollView.contentOffset;

    point.x = point.x+WIDTH;

    [UIView animateWithDuration: animations:^{

        _scrollView.contentOffset = point;

    }completion:^(BOOL finished) {

        CGPoint point1 = _scrollView.contentOffset;

        if (_scrollView.contentOffset.x/WIDTH == self.scrollViewDataArray.count) {

            _scrollView.contentOffset = CGPointZero;

        }

    }];

}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{

    // keyPath为观察的那个key也就是属性，object为观察的的那个对象，change为变化的值

    int x = _scrollView.contentOffset.x/;

    pageController.currentPage = x;

}