UIKit框架-高级控件:2.UIScrollView的单图分页设置

在前面, 我们了解了UIScrollView的基本属性, 也知道了它运作之后的效果, 现在让我们来看看UIScrollView的其他更高级的功能, 那就是分页设置, 下面让我们来看看如何设置分页.

1.设置全局变量:

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

2.在.h文件中设置UIScrollView的Delegate:

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UIScrollViewDelegate>


@end

3.添加一个UIScrollView:

#pragma mark - 添加ScrollView
- (void)myScrollView
{
    // 1.实例化ScrollView
    _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 28, self.view.frame.size.width, self.view.frame.size.height)];
    [_scrollView setBackgroundColor:[UIColor grayColor]];
    
    // 2.设置ScrollView内容
    UIImage *image = [UIImage imageNamed:@"002.jepg"];
    UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
    [_scrollView addSubview:imageView];
    
    // 3.设置ScrollView属性
    [_scrollView setContentSize:image.size];
    [_scrollView setBounces:NO];
    [_scrollView setShowsHorizontalScrollIndicator:NO];
    
    // 4.ScrollView分页设置
    [_scrollView setPagingEnabled:YES];
    
    [self.view addSubview:_scrollView];
    
    // 设置ScrollView为代理
    [_scrollView setDelegate:self];
}

4.设置ScrollView的代理方法

#pragma mark - 设置ScrollView代理方法
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    NSInteger pageNo = scrollView.contentOffset.x / scrollView.bounds.size.width;
    
    [_pageControl setCurrentPage:pageNo];
}

5.添加pageControl

- (void)myPageControl
{
    // 1.添加分页控件
    _pageControl = [[UIPageControl alloc]init];
    
    // 1.1指定位置和大小
    [_pageControl setBounds:CGRectMake(0, 0, 150, 50)];
    [_pageControl setCenter:CGPointMake(self.view.frame.size.width / 2, self.view.frame.size.height - 50)];
    
    // 2.设置页面属性
    [_pageControl setNumberOfPages:2];
    [_pageControl setCurrentPage:0];
    
    [_pageControl setCurrentPageIndicatorTintColor:[UIColor redColor]];
    [_pageControl setPageIndicatorTintColor:[UIColor greenColor]];
    
    // 3.监听分页控制器的变化
    // PS: 第三个参数是ValueChanged
    [_pageControl addTarget:self action:@selector(updatePageChanged:) forControlEvents:UIControlEventValueChanged];
    
    [self.view addSubview:_pageControl];

}

6.添加pageControl的监听方法

#pragma mark 分页控制器的监听方法
- (void)updatePageChanged:(UIPageControl *)pageControl
{
    CGFloat offsetX = pageControl.currentPage * _scrollView.bounds.size.width;
    
    [_scrollView setContentOffset:CGPointMake(offsetX, 0) animated:YES];
}

7.添加所有方法到viewDidload中

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

最后实现的效果:

  

好了, 这次我们就讲到这里, 下次我们继续~~