添加图片轮播器

//当一个对象从xib中创建初始化完毕的时候就会调用一次
-(void)awakeFromNib{
    CGFloat imageH=self.scrollView.frame.size.height;
    CGFloat imageW=self.scrollView.frame.size.width;
    CGFloat imageY=0;
    for (int i=0; i<imageCount; i++) {
        UIImageView *imageView=[[UIImageView alloc]init];
        CGFloat imageX=i*imageW;
        NSString *name=[NSString stringWithFormat:@"ad_0%i",i];
        imageView.image=[UIImage imageNamed:name];
        imageView.frame=CGRectMake(imageX, imageY, imageW, imageH);
        [self.scrollView addSubview:imageView];
    }
    CGFloat contentSize=imageW*imageCount;
    self.scrollView.contentSize=CGSizeMake(contentSize, 0);
    self.scrollView.pagingEnabled=YES;
    self.pageControl.numberOfPages=imageCount;
    self.scrollView.showsHorizontalScrollIndicator=NO;
    [self addTimer];
}
#pragma mark 添加定时器
-(void)addTimer{
    self.timer=[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextImage) userInfo:nil repeats:YES];
    [[NSRunLoop currentRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}
#pragma mark 移除定时器
-(void)removeTimer{
    [self.timer invalidate];
    self.timer=nil;
}
#pragma mark 下一个图片
-(void)nextImage{
    //增加pageControl的页码
    int page=0;
    if (self.pageControl.currentPage==imageCount-1) {
        page=0;
    }else{
        page=self.pageControl.currentPage+1;
    }
    //计算imagescrollView滚动的位置
    CGFloat offsetX=page*self.imagescrollView.frame.size.width;
    CGPoint offset=CGPointMake(offsetX, 0);
    [self.imagescrollView  setContentOffset:offset animated:YES];
}
#pragma mark 代理方法（代理方法非常重要，这个方法关联着pageControl）
-(void)scrollViewDidScroll:(UIScrollView *)imagescrollView{
    //根据imagescrollView滚动的位置决定pageControl显示第几页
    CGFloat scrollW=imagescrollView.frame.size.width;
    int page=(imagescrollView.contentOffset.x+scrollW*0.5)/scrollW;
    self.pageControl.currentPage=page;
}
-(void)scrollViewWillBeginDragging:(UIScrollView *)imagescrollView{
    //停止定时器
    [self removeTimer];
}
-(void)scrollViewDidEndDragging:(UIScrollView *)imagescrollView willDecelerate:(BOOL)decelerate{
    //开启定时器
    [self addTimer];
}