如何使用 NSTimer 在滚动视图中更改图像幻灯片上的页面控制指示器

Question

这是工作正常的图像滑块。手动拖动时，图像会发生变化，指示器也会更改，但是当我添加动画时，只有图像会自动更改，而不是指示器。

我想滚动图像以便指标更改，而不是动画图像 就像拖动时会发生变化一样。我也想给它添加计时器。

@implementation DashboardViewController {
NSArray * animationArray;
}
@synthesize scroller = scroller;
@synthesize pageControl = pageControl;


-
(void) viewDidLoad {
[super viewDidLoad];
scroller.pagingEnabled = YES;
scroller.showsHorizontalScrollIndicator = NO;
scroller.delegate = self;

animationArray = [NSArray arrayWithObjects: [UIImage imageNamed: @ "image1.jpg"],
[UIImage imageNamed: @ "image2.jpg"],
[UIImage imageNamed: @ "image3.jpg"],
[UIImage imageNamed: @ "image4.png"],
[UIImage imageNamed: @ "image5.jpg"],
nil
];

CGRect scrollFrame = CGRectMake(0, 0, self.view.frame.size.width, self.scroller.frame.size.height);
scroller.frame = scrollFrame;

self.scroller.contentSize = CGSizeMake(self.scroller.frame.size.width * animationArray.count, self.scroller.frame.size.height);
for (int i = 0; i < animationArray.count; i++) {
CGRect frame;
frame.origin.x = self.scroller.frame.size.width * i;
frame.origin.y = 0;
frame.size = self.scroller.frame.size;
UIImageView * imgView = [
[UIImageView alloc] initWithFrame: CGRectMake(self.scroller.frame.size.width * i, 0, self.scroller.frame.size.width, self.scroller.frame.size.height)
];
imgView.image = [animationArray objectAtIndex: i];
imgView.frame = frame;
imgView.animationImages      = animationArray;
imgView.animationDuration    = 8;
imgView.animationRepeatCount = 0;
[imgView startAnimating];
[self.scroller addSubview:imgView];
}
self.pageControl.currentPage = 0;
}

-
(void) scrollViewDidScroll: (UIScrollView * ) sender {
if (!pageControlBeingUsed) {
// Switch the indicator when more than 50% of the previous/next page is visible
CGFloat pageWidth = self.scroller.frame.size.width;
int page = floor((self.scroller.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
self.pageControl.currentPage = page;
}
} -
(void) scrollViewWillBeginDragging: (UIScrollView * ) scrollView {
pageControlBeingUsed = NO;
}
-
(void) scrollViewDidEndDecelerating: (UIScrollView * ) scrollView {
[self setIndiactorForCurrentPage];
} -
(void) setIndiactorForCurrentPage {
uint page = scroller.contentOffset.x / scroller.frame.size.width;
[pageControl setCurrentPage: page];


}

-
(IBAction) changePage {
// Update the scroll view to the appropriate page
CGRect frame;
pageControl.currentPage = animationArray.count;
frame.origin.x = self.scroller.frame.size.width * self.pageControl.currentPage;
frame.origin.y = 0;
frame.size = self.scroller.frame.size;
[self.scroller scrollRectToVisible: frame animated: YES];
pageControlBeingUsed = YES;

}

-
(void) didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
self.scroller = nil;
self.pageControl = nil;
}

我想滚动图像以便指标更改，而不是动画图像 就像拖动时会发生变化一样。我也想给它添加计时器。

Answer 1

我认为您必须在 for 循环中设置当前页面才能自动更改带有图像的页面控制。

//move this up
self.pageControl.currentPage = 0;
for (int i = 0; i < animationArray.count; i++) {
CGRect frame;
frame.origin.x = self.scroller.frame.size.width * i;
frame.origin.y = 0;
frame.size = self.scroller.frame.size;
UIImageView * imgView = [
[UIImageView alloc] initWithFrame: CGRectMake(self.scroller.frame.size.width * i, 0, self.scroller.frame.size.width, self.scroller.frame.size.height)
];
imgView.image = [animationArray objectAtIndex: i];
imgView.frame = frame;
imgView.animationImages      = animationArray;
imgView.animationDuration    = 8;
imgView.animationRepeatCount = 0;
[imgView startAnimating];
self.pageControl.currentPage = i; //set i to current page
[self.scroller addSubview:imgView];
}