UIKit框架-高级控件:3.UIScrollView的多图分页设置

在前面我们学会了如何给UIScrollView的单图分页, 下面让我们来看看, 如何给UIScrollView多图分页.

1.设置代理以及设置全局变量

.h文件

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UIScrollViewDelegate>


@end

.m文件

@interface ViewController ()
{
    UIScrollView *_scrollView;
    UIPageControl *_pageControl;
}
@end

2.实例化UIScrollView

- (void)myScrollView
{
    // 1.实例化UIScrollView
    _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 28, self.view.frame.size.width, self.view.frame.size.height)];
    
    CGFloat width = _scrollView.bounds.size.width;
    CGFloat height = _scrollView.bounds.size.height;
    
    // 2.添加Image内容
    for (NSUInteger i = 1; i <= 5; i++) {
        
        NSString *imageFile = [NSString stringWithFormat:@"%ld.jpg", i];
        UIImage *image = [UIImage imageNamed:imageFile];
        UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
        
        [imageView setFrame:CGRectMake((i - 1) * width, 0, width, height)];
        
        [_scrollView addSubview:imageView];
    }
    
    [_scrollView setBounces:NO];
    [_scrollView setShowsHorizontalScrollIndicator:NO];
    [_scrollView setContentSize:CGSizeMake(5 * width, height)];
    
    [_scrollView setPagingEnabled:YES];
    
    [self.view addSubview:_scrollView];
    
    [_scrollView setDelegate:self];
}

3.添加UIScrollView的代理方法

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    CGFloat pageNo = scrollView.contentOffset.x / scrollView.bounds.size.width;
    [_pageControl setCurrentPage:pageNo];
}

4.添加UIPageControl

- (void)myPageControl
{
    _pageControl = [[UIPageControl alloc] init];
    [_pageControl setBounds:CGRectMake(0, 0, 150, 50)];
    [_pageControl setCenter:CGPointMake(self.view.frame.size.width / 2, self.view.frame.size.height - 50)];
    
    [_pageControl setNumberOfPages:5];
    [_pageControl setCurrentPage:0];
    
    [_pageControl setCurrentPageIndicatorTintColor:[UIColor redColor]];
    [_pageControl setPageIndicatorTintColor:[UIColor greenColor]];
    
    [_pageControl addTarget:self action:@selector(updatePageChanged:) forControlEvents:UIControlEventValueChanged];
    
    [self.view addSubview:_pageControl];
}

5.添加UIPageControl的坚挺方法

- (void)updatePageChanged:(UIPageControl *)pageControl
{
    CGFloat offsetX = pageControl.currentPage * _scrollView.bounds.size.width;
    
    [_scrollView setContentOffset:CGPointMake(offsetX, 0) animated:YES];
}

6.最后把所有方法都实现

- (void)viewDidLoad {
    [super viewDidLoad];
    [self myScrollView];
    [self myPageControl];
}

下面让我们来看看最终效果:

好了, 这次我们就讲到这里, 下次我们继续~~~