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我有一个启用了分页的 UIScrollView。但是，我希望此滚动视图在经过一定时间后向右滚动。有没有一种简单的方法来实现这一点，还是我需要使用计时器并以编程方式滚动滚动视图？

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4 回答 4

14

您需要一个小方法来帮助您滚动到确切的页面，这没有实现，但它非常简单，假设您的滚动视图被调用myScrollview

这假设您正在水平滚动，您可以切换代码以满足您的需要

-(void)scrollToPage:(NSInteger)aPage{
    float myPageWidth = [myScrollView frame].size.width;
    [myScrollView setContentOffset:CGPointMake(aPage*myPageWidth,y) animated:YES];
}

然后你设置一个定时器来每隔 5 秒调用一次这个方法，例如：

[[NSTimer scheduledTimerWithTimeInterval:5
                                  target:self
                                selector:@selector(scrollPages)
                                userInfo:Nil
                                 repeats:YES] fire];

下一步是创建将由计时器触发并滚动到下一页的方法，我称之为它-(void)scrollPages，它还要求您有两个名为currentPageand的全局变量numberOfPages，两者都是类型NSInteger

-(void)scrollPages{
    [self scrollToPage:currentPage%numberOfPages];
    currentPage++;
}

如果有什么不明白的，请告诉我！

于 2013-06-18T12:40:51.170 回答
1

在stackoverflow上找到了这个

[scrollView setContentOffset:CGPointMake(x, y) animated:YES];

要使用 UIScrollView 进行幻灯片放映，您可以在滚动视图中排列所有图像，设置重复计时器，然后 -setContentOffset:animated: 当计时器触发时。

于 2013-06-18T12:25:38.783 回答
0

在您的 .h 文件中为滚动视图和分页创建出口

@property (weak, nonatomic) IBOutlet UIScrollView *sliderScrollView;
@property (weak, nonatomic) IBOutlet UIPageControl *sliderPageControll;
@property (nonatomic,strong) NSArray *sliderImagesArray;
@property (nonatomic,strong) NSString *sliderIndexString;
@property (nonatomic,strong) NSString *currentPageIndexString;

之后在你的 .m 文件中

[self.sliderScrollView setPagingEnabled:YES];
[self.sliderScrollView setBounces:NO];
[self.sliderScrollView setAlwaysBounceVertical:NO];
[self.sliderScrollView setShowsHorizontalScrollIndicator:NO];
self.sliderScrollView.alwaysBounceVertical = NO;
NSArray *imagesArray = self.sliderImagesArray;
for (int i = 0; i < [imagesArray count]; i++){
            CGFloat xOrigin = i * self.imageSliderScrollView.frame.size.width;
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(xOrigin, 0, self.sliderScrollView.frame.size.width, self.sliderScrollView.frame.size.height)];
                imageView.userInteractionEnabled = YES;
    NSString *imgStr = [serviceImgArray objectAtIndex:i];
    NSString *bikeStr = [NSString stringWithFormat:@"%@", imgStr];
    NSURL *imageURL = [NSURL URLWithString:[bikeStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
    [imageView sd_setImageWithURL:imageURL
                       placeholderImage:[UIImage imageNamed:@"profilepic_bg"]];
[imageView setContentMode:UIViewContentModeScaleAspectFill];
                [self.sliderScrollView addSubview:imageView];
}
// for adding autorotate scrolling
   [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(autoStartSlide:) userInfo:nil repeats:YES];

self.sliderPageControll.numberOfPages = imagesArray.count;
self.sliderPageControll.currentPage = 0;
self.currentPageIndexString = [NSString stringWithFormat:@"%ld",(long)0];
[self.sliderScrollView setContentSize:CGSizeMake(self.sliderScrollView.frame.size.width * [imagesArray count], self.sliderScrollView.frame.size.height)];

if ([self.sliderPageControll respondsToSelector:@selector(setPageIndicatorTintColor:)]) {
    self.sliderPageControll.currentPageIndicatorTintColor = [UIColor redColor];
    self.sliderPageControll.pageIndicatorTintColor = [UIColor whiteColor];
}

CGRect frame = self.sliderScrollView.frame;
frame.origin.x = frame.size.width * [[NSString stringWithFormat:@"%@",self.sliderIndexString] integerValue];
frame.origin.y = 0;
[self.sliderScrollView scrollRectToVisible:frame animated:NO];
self.sliderPageControll.currentPage = [[NSString stringWithFormat:@"%@",self.sliderIndexString] integerValue];

之后实现滚动视图委托方法

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
NSInteger scrollIndex = (NSInteger)(self.sliderScrollView.contentOffset.x / self.sliderScrollView.frame.size.width);
self.sliderPageControll.currentPage = scrollIndex;
self.currentPageIndexString = [NSString stringWithFormat:@"%ld",(long)self.sliderPageControll.currentPage];
}

在这里实现你的 autotrotate 方法。

 - (void)autoStartSlide:(id)sender {
if(pagger.numberOfPages > pagger.currentPage+1) {
    [UIView animateWithDuration:0.5 animations:^{
        slider.contentOffset = CGPointMake(slider.contentOffset.x + slider.frame.size.width, 0);
    } completion:^(BOOL finished) {

    }];
}
else {
    slider.contentOffset = CGPointMake(slider.contentOffset.x - slider.frame.size.width, 0);
    [UIView animateWithDuration:0.5 animations:^{
        slider.contentOffset = CGPointMake(slider.contentOffset.x + slider.frame.size.width, 0);
    } completion:^(BOOL finished) {
        slider.contentOffset = CGPointMake(0, 0) ;
    }];
}
}
于 2017-02-01T12:27:12.177 回答
0

这是一个兼容 Swift 5 的

var currentPage = 1;
var slideTimer : Timer?

ViewDidLoad

 slideTimer = Timer.scheduledTimer(timeInterval: 3, target: self, selector: #selector(scrollPages), userInfo: nil, repeats: true)

viewDidDisappear

slideTimer?.invalidate()

功能

@objc func scrollPages() {
        scrollToPage(page: CGFloat(currentPage%slides.count));
        currentPage+=1;
    }
    
    func scrollToPage(page : CGFloat) {
        let pageWidth = scrollView.frame.width
        scrollView .setContentOffset(CGPoint(x: pageWidth * page, y: 0.0), animated: true)
    }
于 2021-05-16T16:46:53.390 回答