Question

我对iOS开发很陌生，我偶然发现了一些我无法轻易找到答案的问题：

常规设置：我在TabBarApplication

中使用带有PageControl的ScrollView

是否可以将PageControl与页面内容放在同一区域内？对我来说，它总是被SrollView的视图隐藏，但由于显示空间很少，我真的需要它与实际内容的高度相同。
我在一些Sandbox-Project中愚弄了，每当我第一次开始在ScrollView-Page的视图中实现一个按钮时，ScrollView的页面就不会立即显示，但只有在第一个之后滚动尝试。我会发布一些代码，但它基本上只能从IB自动生成。
这是关于可能性的一般性问题：项目的主要设计应该是带有NavigationController的TabBarApplication，让你更深入地了解子菜单，就像它很常见。现在在其中一个选项卡中应该有PageControl，然后您可以通过在NavigationController堆栈上推送Views再次进入子菜单。这可能吗？

2的一些代码。

- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];

NSMutableArray *controllers = [[NSMutableArray alloc] init];
for (unsigned i = 0; i < kNumberOfPages; i++) {
    [controllers addObject:[NSNull null]]; // [TaskPageViewController new]];
}
self.viewControllers = controllers;
[controllers release];

// a page is the width of the scroll view
scrollView.pagingEnabled = YES;
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * kNumberOfPages, scrollView.frame.size.height);
scrollView.showsHorizontalScrollIndicator = NO;
scrollView.showsVerticalScrollIndicator = NO;
scrollView.scrollsToTop = NO;
scrollView.delegate = self;

pageControl.numberOfPages = kNumberOfPages;
pageControl.currentPage = 0;

}
- (IBAction)changePage:(id)sender {
int page = pageControl.currentPage;
// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];
// update the scroll view to the appropriate page
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];
// Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above.
pageControlUsed = YES;

}

- (void)loadScrollViewWithPage:(int)page {
if (page < 0) return;
if (page >= kNumberOfPages) return;

// replace the placeholder if necessary
TaskPageViewController *controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
    controller = [[TaskPageViewController alloc] init]; //WithPageNumber:page];
    [viewControllers replaceObjectAtIndex:page withObject:controller];
    [controller release];
}

// add the controller's view to the scroll view
if (nil == controller.view.superview) {
    CGRect frame = scrollView.frame;
    frame.origin.x = frame.size.width * page;
    frame.origin.y = 0;
    controller.view.frame = frame;
    [scrollView addSubview:controller.view];
}
}

- (void)scrollViewDidScroll:(UIScrollView *)sender {
// We don't want a "feedback loop" between the UIPageControl and the scroll delegate in
// which a scroll event generated from the user hitting the page control triggers updates from
// the delegate method. We use a boolean to disable the delegate logic when the page control is used.
if (pageControlUsed) {
    // do nothing - the scroll was initiated from the page control, not the user dragging
    return;
}
// Switch the indicator when more than 50% of the previous/next page is visible
CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
pageControl.currentPage = page;

// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];

// A possible optimization would be to unload the views+controllers which are no longer visible
}

Answer 1

您可以为此设置两个视图层次结构：
- 将页面控件放在scrollview中，原点固定为contentOffset属性
- 在scrollView的superview中有页面控件，但索引更高（即浮动在它上面）
这取决于您添加子视图的代码的位置。它是在scrollView的委托方法中吗？ viewDidLoad？别的地方？有些代码可能会有所帮助。
在向下钻取导航时，不确定为什么需要页面控件。页面用于导航相同级别的项目。

关于使用PageControl的ScrollView的几个问题

1 个答案: