#import "PageViewController.h"

@interface PageViewController () <UIScrollViewDelegate>

@property (strong, nonatomic) UIScrollView *scrollView;

@property (strong, nonatomic) NSArray *contentList;

@property (strong, nonatomic) UIPageControl *pageControl;

#define pageControlHeight 70

@implementation PageViewController

- (void)viewDidLoad {

[super viewDidLoad];

// 1.初始化数组

self.contentList = @[@"one", @"two", @"three", @"four", @"five"];

// 2.将scrollView和pageControl添加到view 设定控制器背景颜色

[self.view addSubview:self.scrollView];

[self.view addSubview:self.pageControl];

self.view.backgroundColor = [UIColor blackColor];

// 3.为scrollView每一页添加图片

for (NSUInteger i=0; i<self.contentList.count; ++i) {

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(CGRectGetWidth(self.scrollView.frame) * i, 0, CGRectGetWidth(self.scrollView.frame), CGRectGetHeight(self.scrollView.frame))];

imageView.contentMode = UIViewContentModeScaleAspectFit;

imageView.image = [UIImage imageNamed:self.contentList[i]];

[self.scrollView addSubview:imageView];

}

}

- (UIStatusBarStyle)preferredStatusBarStyle {

return UIStatusBarStyleLightContent;

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

#pragma mark - Properties

- (UIScrollView *)scrollView {

if (!_scrollView) {

_scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, pageControlHeight, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame) - 2*pageControlHeight)];

_scrollView.contentSize = CGSizeMake(CGRectGetWidth(self.view.frame) * self.contentList.count, CGRectGetHeight(self.view.frame) - 2*pageControlHeight);

_scrollView.backgroundColor = [UIColor whiteColor];

_scrollView.pagingEnabled = YES;

_scrollView.delegate = self;

_scrollView.showsHorizontalScrollIndicator = NO;

}

return _scrollView;

}

- (UIPageControl *)pageControl {

if (!_pageControl) {

_pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, CGRectGetHeight(self.view.frame) - pageControlHeight, CGRectGetWidth(self.view.frame), pageControlHeight)];

_pageControl.numberOfPages = self.contentList.count;

_pageControl.currentPage = 0;

[_pageControl addTarget:self action:@selector(changePage:) forControlEvents:UIControlEventValueChanged];

}

return _pageControl;

}

#pragma mark - UIScrollViewDelegate

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

CGFloat pageWidth = CGRectGetWidth(self.scrollView.frame);

NSUInteger page = floor((scrollView.contentOffset.x - pageWidth/2)/pageWidth) + 1;

self.pageControl.currentPage = page;

}

#pragma mark - IBAction

- (void)changePage:(id)sener {

NSUInteger page = self.pageControl.currentPage;

CGRect bounds = self.scrollView.bounds;

bounds.origin.x = CGRectGetWidth(bounds) * page;

bounds.origin.y = self.scrollView.frame.origin.y;

[self.scrollView scrollRectToVisible:bounds animated:YES];

}