我读到的关于在 iOS 5+ 上支持 UIScrollView 的所有内容都表明我应该能够使用 Xcode 的 Size Inspector 中的自动调整大小功能来自动调整我的视图大小。
使用 Storyboards,我有一个 TabBarViewController,其中一个选项卡有一个 UIScrollView 和一个页面控件。
在幕后,我以编程方式设置了 UIView 中页面的处理(我不知道是否有必要发布代码,但为了清楚起见我还是会这样做)。
从 iPhone 3.5 英寸切换到 iPhone 4 英寸时,自动调整大小不起作用。在使用 3.5 英寸屏幕时,我希望 UIScrollView 和 Page 控件可见。
我应该注意到 iPad 版本(见下面的代码)在我的子视图中没有正确捕捉。(这可能是一个完全不同的问题)。
4寸屏幕
3.5寸屏幕
以防万一,这是我的 .m 文件:
#import "TutorialViewController.h"
@interface TutorialViewController ()
@property (nonatomic, strong) NSArray *pageImages;
@property (nonatomic, strong) NSMutableArray *pageViews;
- (void)loadVisiblePages;
- (void)loadPage:(NSInteger)page;
- (void)purgePage:(NSInteger)page;
#ifdef UI_USER_INTERFACE_IDIOM
#define IS_IPAD() (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
#else
#define IS_IPAD() (false)
#endif
@end
@implementation TutorialViewController
@synthesize scrollView = _scrollView;
@synthesize pageControl = _pageControl;
@synthesize pageImages = _pageImages;
@synthesize pageViews = _pageViews;
- (void)loadPage:(NSInteger)page {
if (page < 0 || page >= self.pageImages.count) {
// If it's outside the range of what you have to display, then do nothing
return;
}
// 1
UIView *pageView = [self.pageViews objectAtIndex:page];
if ((NSNull*)pageView == [NSNull null]) {
// 2
CGRect frame = self.scrollView.bounds;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0.0f;
// 3
UIImageView *newPageView = [[UIImageView alloc] initWithImage:[self.pageImages objectAtIndex:page]];
newPageView.contentMode = UIViewContentModeScaleAspectFill;
newPageView.frame = frame;
[self.scrollView addSubview:newPageView];
// 4
[self.pageViews replaceObjectAtIndex:page withObject:newPageView];
}
}
- (void)purgePage:(NSInteger)page {
if (page < 0 || page >= self.pageImages.count) {
// If it's outside the range of what you have to display, then do nothing
return;
}
// Remove a page from the scroll view and reset the container array
UIView *pageView = [self.pageViews objectAtIndex:page];
if ((NSNull*)pageView != [NSNull null]) {
[pageView removeFromSuperview];
[self.pageViews replaceObjectAtIndex:page withObject:[NSNull null]];
}
}
- (void)loadVisiblePages {
// First, determine which page is currently visible
CGFloat pageWidth = self.scrollView.frame.size.width;
NSInteger page = (NSInteger)floor((self.scrollView.contentOffset.x * 2.0f + pageWidth) / (pageWidth * 2.0f));
// Update the page control
self.pageControl.currentPage = page;
// Work out which pages you want to load
NSInteger firstPage = page - 1;
NSInteger lastPage = page + 1;
// Purge anything before the first page
for (NSInteger i=0; i<firstPage; i++) {
[self purgePage:i];
}
// Load pages in our range
for (NSInteger i=firstPage; i<=lastPage; i++) {
[self loadPage:i];
}
// Purge anything after the last page
for (NSInteger i=lastPage+1; i<self.pageImages.count; i++) {
[self purgePage:i];
}
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
// Load the pages that are now on screen
[self loadVisiblePages];
// NSLog(@"Scroll View Did Scroll");
}
- (void)viewDidLoad {
[super viewDidLoad];
// Step 1
if (IS_IPAD())
{
self.pageImages = [NSArray arrayWithObjects:
[UIImage imageNamed:@"1536x2048 tutorial_1.png"],
[UIImage imageNamed:@"1536x2048 tutorial_2.png"],
[UIImage imageNamed:@"1536x2048 tutorial_3.png"],
[UIImage imageNamed:@"1536x2048 tutorial_4.png"],
nil];
}
else
{
self.pageImages = [NSArray arrayWithObjects:
[UIImage imageNamed:@"640x960 tutorial_1.png"],
[UIImage imageNamed:@"640x960 tutorial_2.png"],
[UIImage imageNamed:@"640x960 tutorial_3.png"],
[UIImage imageNamed:@"640x960 tutorial_4.png"],
nil];
}
NSInteger pageCount = self.pageImages.count;
// Step 2
self.pageControl.currentPage = 0;
self.pageControl.numberOfPages = pageCount;
// Step 3
self.pageViews = [[NSMutableArray alloc] init];
for (NSInteger i = 0; i < pageCount; ++i) {
[self.pageViews addObject:[NSNull null]];
}
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
// Step 4
// 3.5in height = 388
// 4in height = 476
CGSize pagesScrollViewSize = self.scrollView.frame.size;
self.scrollView.contentSize = CGSizeMake(pagesScrollViewSize.width * self.pageImages.count, pagesScrollViewSize.height);
// Step 5
[self loadVisiblePages];
}
@end