UIScrollViewAndUIPageController结合使用

qq_33051421

于 2016-01-27 22:32:41 发布

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分类专栏： IOS开发

本文链接：https://blog.youkuaiyun.com/qq_33051421/article/details/50597008

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本文介绍了一个使用Swift实现的iOS应用，通过定时器自动滚动一组图片，并通过UIPageControl同步显示当前页面。当用户手动拖动图片时，会触发相应的逻辑更新UIPageControl，实现流畅的交互体验。

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.h文件代码

@interface ViewController : UIViewController<UIScrollViewDelegate>

{
    UIScrollView *_scrollView;
    UIPageControl *_pageControl;
    NSTimer *_timer;
    int _speed;
}

@end

.m文件代码

- (void)viewDidLoad
{
    [super viewDidLoad];

    _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 20, 320, 200)];
    _scrollView.contentSize = CGSizeMake(5 *320, 200);
    for (int a = 0;   a < 5; a++)
    {
        UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(a *320, 0, 320, 200)];
        NSString *imageStr = [NSString stringWithFormat:@"image%d.jpg",a+1];
        imageView.image = [UIImage imageNamed:imageStr];

        [_scrollView addSubview:imageView];
    }
    _scrollView.pagingEnabled = YES;
    _scrollView.bounces = NO;

    _scrollView.delegate = self;

    [self.view addSubview:_scrollView];

    _pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(100, 200, 140, 20)];
    _pageControl.numberOfPages = 5;

    _pageControl.currentPageIndicatorTintColor = [UIColor yellowColor];
    _pageControl.pageIndicatorTintColor = [UIColor blackColor];
    [_pageControl addTarget:self action:@selector(valueChange) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:_pageControl];

    设置定时器,使图片自动滚动
    _timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];

}

- (void)onTimer
{
    if (_pageControl.currentPage == 0)
    {
        _speed = 1;
    }
    if (_pageControl.currentPage == 4)
    {
        _speed = -1;
    }


    _pageControl.currentPage = _pageControl.currentPage + _speed;

    [_scrollView setContentOffset:CGPointMake(_pageControl.currentPage *320, 0) animated:YES];
}
当拖动图片的时候,使pageControl的当前显示点一起改变
- (void)valueChange
{
    [_scrollView setContentOffset:CGPointMake(_pageControl.currentPage *320, 0) animated:YES];
}

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    //[_timer invalidate];
   // _timer = nil;
}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{

}

- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{

}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    //在scrollView已经结束减速的时候, 更改pageControl.currentPage属性的值;

    //根据scrollView的偏移量/320, 计算当前小圆点所处于的位置;
    _pageControl.currentPage = _scrollView.contentOffset.x/320;
    NSLog(@"_scrollView.contentOffSet = %f",_scrollView.contentOffset.x);
    NSLog(@"_pageControl.currentPage = %d",_pageControl.currentPage);

    _timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];
}

具体代码