首页 > 代码库 > 使用UIScrollView和UIPageControl做一个可以用手势来切换图片的效果
使用UIScrollView和UIPageControl做一个可以用手势来切换图片的效果
利用UIScrollView的滚动效果来实现,先上图:
实现过程是:在viewController里先加入UIScrollView和UIPageControl:
-(void) loadView { [super loadView]; UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320,480)]; UIPageControl* pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, 438, 320, 42)]; self.scrollView = scrollView; self.pageControl = pageControl; self.pageControl.opaque = 1; [self.pageControl addTarget:self action:@selector(changePage:) forControlEvents:UIControlEventValueChanged]; [self.view addSubview:self.scrollView]; [self.view addSubview:self.pageControl]; }
然后来初始化UIScrollView:
- (void)viewDidLoad { [super viewDidLoad]; self.contentList = [NSArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5", nil]; NSMutableArray* controllers = [[NSMutableArray alloc] init]; for (unsigned i = 0 ; i < kNumberOfPages; i++) { [controllers addObject:[NSNull null]]; } self.viewControllers = controllers; self.scrollView.pagingEnabled = YES; //contentSize是内容的宽度 self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width*kNumberOfPages, self.scrollView.frame.size.height); self.scrollView.showsHorizontalScrollIndicator = NO; self.scrollView.showsVerticalScrollIndicator = NO; self.scrollView.scrollsToTop = NO; self.scrollView.delegate = self; self.pageControl.numberOfPages = kNumberOfPages; self.pageControl.currentPage = 0; [self loadScrollViewWithPage:0]; [self loadScrollViewWithPage:1]; // Do any additional setup after loading the view. } //UserImageViewController里只有一个UIImageView -(void) loadScrollViewWithPage:(int)page{ if (page < 0) { return; }else if(page >= kNumberOfPages) { //do some thing,like jump to other screen CalendarViewExample* calendarView = [[CalendarViewExample alloc] init]; [self presentViewController:calendarView animated:YES completion:^{}]; return; } UserImageViewController* controller = [self.viewControllers objectAtIndex:page]; if ((NSNull*)controller == [NSNull null]) { controller = [[UserImageViewController alloc] init]; [self.viewControllers replaceObjectAtIndex:page withObject:controller]; } if (controller.view.superview == nil) { CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * page; frame.origin.y = 0; controller.view.frame = frame; [self.scrollView addSubview:controller.view]; NSString* name =[self.contentList objectAtIndex:page]; NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:@"jpg"]; controller.numberImage.image = [UIImage imageWithContentsOfFile:path]; } }
如果用手指来滚动的时候:
-(void) scrollViewDidScroll:(UIScrollView *)scrollView{ if (pageControlUsed) { return; } CGFloat pageWidth = scrollView.frame.size.width; //page表示当前滚动哪一页的标识 int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth)+1; self.pageControl.currentPage = page; [self loadScrollViewWithPage:page-1]; [self loadScrollViewWithPage:page]; [self loadScrollViewWithPage:page+1]; } -(void) scrollViewWillBeginDecelerating:(UIScrollView *)scrollView { pageControlUsed = NO; } -(void) scrollViewDidEndDecelerating:(UIScrollView *)scrollView { pageControlUsed = NO; }
然后如果切换到下一页:
-(void) changePage:(id)sender{ int page = self.pageControl.currentPage; NSLog(@"chanepage page=%d",page); [self loadScrollViewWithPage:page-1]; [self loadScrollViewWithPage:page]; CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width*page; frame.origin.y = 0; [self.scrollView scrollRectToVisible:frame animated:YES]; pageControlUsed = YES; }代码可以在http://download.csdn.net/detail/baidu_nod/7547659下载
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