scrollView 循环滚动

#import "QHMainController.h"

@interface QHMainController ()<UIScrollViewDelegate>
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;
@property(nonatomic,strong) NSTimer *timer;
@end

@implementation QHMainController

- (void)viewDidLoad {
    [super viewDidLoad];
    int totalPage = 5;
    CGFloat btnW = self.scrollView.frame.size.width;
    CGFloat btnH = self.scrollView.frame.size.height;
    
    for (int i = 0; i < totalPage; i++) {
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        
        NSString *name = [NSString stringWithFormat:@"ad_%02d",i];
        UIImage *image = [UIImage imageNamed:name];
        
        [btn setBackgroundImage:image forState:UIControlStateNormal];
        CGFloat btnX = i*btnW;
        CGFloat btnY = 0;

        btn.frame = CGRectMake(btnX, btnY, btnW, btnH);
        
        [self.scrollView addSubview:btn];
    }
    
    _scrollView.contentSize = CGSizeMake(totalPage*btnW, btnH);
    _scrollView.pagingEnabled = YES;
    _scrollView.showsHorizontalScrollIndicator = NO;
    
    //设置代理有两种方式 设置
    _scrollView.delegate = self;
    //设置pageControl的属性
    self.pageControl.numberOfPages = totalPage;
    self.pageControl.currentPage = 0;
    
    [self startTimer];

}


-(void)startTimer
{
     //添加一个定时器
    NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(autoScroll) userInfo:nil repeats:YES];
    self.timer = timer;
    [[NSRunLoop currentRunLoop]addTimer:self.timer forMode:NSRunLoopCommonModes];
    
}

-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    [self.timer invalidate];
}

-(void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
    [self startTimer];
}
-(void)autoScroll
{
    //1.得到偏移量
    //2如何得大滚动的位置
    int totalPage = 5;
    int page = self.pageControl.currentPage >=totalPage -1?0:self.pageControl.currentPage+1;
    self.scrollView.contentOffset = CGPointMake(page*self.scrollView.frame.size.width, 0);

}


//只要发生滚动就会自动调用
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGPoint contentOffSet = self.scrollView.contentOffset;
    
    int page = (contentOffSet.x + self.scrollView.frame.size.width*0.5)/self.scrollView.frame.size.width;
    
    self.pageControl.currentPage = page;
}
-(BOOL)prefersStatusBarHidden
{
    return YES;
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end