objective-c - 如何将 Scrollview 滚动到边界之外

Question

嗨，我的应用程序需要在水平列表中以中心焦点显示图像列表。使用UIScrollViewand可以正常工作PagingEnable=Yes；现在我无法滚动显示在UIScrollView边界之外的内容。

如何将 UiscrollView 滚动到边界之外。

Answer 1

假设您有一个与图像高度相同的容器视图，但其大小使所有图像都可以放入其中。每个图像的帧都会有一个“x”偏移量，将其放在图像的末尾。现在假设您的容器中有 3 张图片，每张 320 宽，总共 960 张。

鉴于此，您必须设置 scrollView.contentSize = CGSizeMake(960, 320);

Answer 2

在这里，我给出了一些关于如何水平管理滚动视图的教程，如下所示。

.h 文件包含

@property (nonatomic, strong) NSArray *arForImages; // array for storing images URL
@property (nonatomic, strong) IBOutlet UIScrollView *scrPage; // scroll view used as PageCtr
@property (nonatomic, strong) IBOutlet HJManagedImageV *imgV; // Image to display selected
@property (nonatomic, strong) IBOutlet UILabel *lblName; // label to display selected's title
@property (nonatomic, readwrite) NSUInteger currentPage; // to mantain current page

.m 文件包含

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.arForImages = [NSArray arrayWithObjects:@"http://www.apple.com/in/iphone/iphone-3gs/images/iphone-phone-20100607.jpg",@"http://www.apple.com/in/iphone/iphone-3gs/images/iphone-ibooks-20100607.jpg",@"http://www.blogcdn.com/www.engadget.com/media/2007/01/apple-iphone-official-1.jpg",@"http://www.dailytechpost.com/wp-content/uploads/2011/08/iphone-3G1.jpg",@"http://www.iunlockiphone3g.com/wp-content/uploads/2011/01/Apple-Iphone-India-Launch1.jpg",@"http://st2.gsmarena.com/vv/pics/apple/apple-iphone-3g-01.jpg",@"http://resources.infosecinstitute.com/wp-content/uploads/iphone.jpg",@"http://bindapple.com/wp-content/uploads/2011/01/can-iphones-get-viruses1.jpg",@"http://www.coolpctips.com/wp-content/uploads/2011/08/iphone-mailbox.jpg",@"http://www.everymac.com/images/other_images/iphone-iphone-3g-comparison.jpg",@"http://iphone4issues.org/wp-content/uploads/2011/07/Iphone-4-Issues1.jpg",nil];

    [self setupImages];
}

滚动视图的分页

#define kXDistance    5
#define kYDistance    5
#define kThumbWidth   58
#define kThumbHeight   58
#define kTagForImageView    10000

- (void)setupImages {
    // This will remove all subview from your scrollView
    [[self.scrPage subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];

    // set the content size of your scrollView to number of object that you have in your array
    self.scrPage.contentSize=CGSizeMake((self.arForImages.count+4)*63, 68);

    // we will start from two in this tutorial, you can start from one also.
    NSUInteger i=2; // images starting from location 2
    for (NSString *str in self.arForImages) {
        // buttons will have images within it & we will add buttons to scrollView
        UIButton *btn=[UIButton buttonWithType:UIButtonTypeCustom];
        NSUInteger xVal=(i+1)*kXDistance;
        xVal = xVal + (i*kThumbWidth);
        [btn setFrame:CGRectMake(xVal, kYDistance, kThumbWidth, kThumbHeight)];
        btn.tag=i-1; // index tagging strating from 1

        HJManagedImageV *imgV=[[HJManagedImageV alloc] initWithFrame:CGRectMake(0, 0, kThumbWidth, kThumbHeight)];
        imgV.tag=kTagForImageView;
        imgV.url=[NSURL URLWithString:[self.arForImages objectAtIndex:i-2]];
        imgV.clipsToBounds=YES;
        imgV.layer.borderColor = [[UIColor blackColor] CGColor];
        imgV.layer.borderWidth = 1;
        imgV.layer.cornerRadius = 3;

        // here GlobalCacheManager is an object declared in AppDel which is accessed via a Constant
        [GlobalCacheManager manage:imgV];

        [btn addTarget:self action:@selector(btnTapped:) forControlEvents:UIControlEventTouchDown];
        [btn addSubview:imgV];

        [self.scrPage addSubview:btn];
        i++;
    }
    self.lblName.text=[[self.arForImages objectAtIndex:0] lastPathComponent];
    self.imgV.url=[NSURL URLWithString:[self.arForImages objectAtIndex:0]];
    [GlobalCacheManager manage:self.imgV];
    self.currentPage = 0;
}

- (void)btnTapped:(UIButton*)btn {
    self.scrPage.delegate=nil;
    CGRect rectToScroll = btn.frame;
    rectToScroll=CGRectMake(rectToScroll.origin.x-63-63, kYDistance, 320, 68);
    [self.scrPage scrollRectToVisible:rectToScroll animated:YES];
    self.lblName.text=[[self.arForImages objectAtIndex:btn.tag-1] lastPathComponent];
    self.imgV.url=[NSURL URLWithString:[self.arForImages objectAtIndex:btn.tag-1]];
    [GlobalCacheManager manage:self.imgV];
    [self.scrPage performSelector:@selector(setDelegate:) withObject:self afterDelay:0.3];
}

希望这可能对您有所帮助。