如何在UIScrollView中添加UIPageControl

Question

This is my UIScrollView function, i displayed 7 images out of 39 in one page. It works but I want to display and change the UIPageControl .

- (void)layoutScrollImages{
  UIImageView *view = nil;
  NSArray *subviews = [scrollView1 subviews];

  curXLoc = 0;
  for (view in subviews)
  {
    if ([view isKindOfClass:[UIImageView class]] && view.tag > 0)
    {
        CGRect frame = view.frame;
        frame.origin = CGPointMake(curXLoc, 0);
        view.frame = frame;

        curXLoc += (kScrollObjWidth);

    }
}

// set the content size so it can be scrollable
[scrollView1 setContentSize:CGSizeMake((kNumImages * kScrollObjWidth), [scrollView1 bounds].size.height)];
}

- (void)viewDidLoad {

    kScrollObjHeight    = 172.0;
    kScrollObjWidth = 146.0;
    kNumImages      = 39;
    scrollView1=[[UIScrollView alloc]initWithFrame:CGRectMake(0, 596, 1022, 172)];

    scrollView1.showsVerticalScrollIndicator=YES;
    scrollView1.userInteractionEnabled=YES;
    [self.view addSubview:scrollView1];

    self.view.backgroundColor = [UIColor whiteColor];
    [scrollView1 setBackgroundColor:[UIColor whiteColor]];
[scrollView1 setCanCancelContentTouches:NO];
scrollView1.indicatorStyle = UIScrollViewIndicatorStyleWhite;

scrollView1.clipsToBounds = NO;
scrollView1.scrollEnabled = YES;
scrollView1.pagingEnabled = YES;

    NSUInteger j;
for (j = 1; j <= kNumImages; j++)
{
    NSString *imageName = [NSString stringWithFormat:@"thumb_%lu.png",(unsigned long)j];
    image = [UIImage imageNamed:imageName];
    imageView = [[UIImageView alloc] initWithImage:image];

    CGRect rect = imageView.frame;
    rect.size.height = kScrollObjHeight;
    rect.size.width = kScrollObjWidth;
    imageView.frame = rect;
    imageView.tag = j;  // tag our images for later use when we place them in serial fashion

    [scrollView1 addSubview:imageView];
}

    pageCtrl = [[UIPageControl alloc] init];
    pageCtrl.frame = CGRectMake(-130, CGRectGetMidY(self.view.bounds)+25, 1024, 100);
    [pageCtrl setNumberOfPages:5];
    pageCtrl.currentPage = 0;
    pageCtrl.pageIndicatorTintColor = [UIColor lightGrayColor];
    pageCtrl.currentPageIndicatorTintColor = [UIColor blackColor];
   [self.view addSubview:pageCtrl];
 }

How can I use UIPageControl here?

Answer 1

Add Target for Page control like as follows,

[pageControl addTarget:self action:@selector(onPageControlPageChanged:) forControlEvents:UIControlEventValueChanged];

then,

- (void)onPageControlPageChanged:(UIPageControl *)pageControl_ {

    int offsetX = pageControl_.currentPage * kScrollObjWidth;

    CGPoint offset = CGPointMake(offsetX, 0);

    [scrollView setContentOffset:offset animated:YES];
}

.

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView_ {

    int page = scrollView.contentOffset.x / scrollView.frame.size.width;
    pageCtrl.currentPage = page;
}

Answer 2

at - (void)scrollViewDidScroll:(UIScrollView *)scrollView; You count currentPage and set like

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    pageCtrl.currentPage = (int)(self.scrollView.contentOffset.x / kScrollObjWidth);
    }