iOS UIScrollView实用之图片轮播 —— HERO博客

上一篇简述了UIScrollView的属性及方法，本篇实际应用制作图片轮播效果。

具体属性及方法可以参考上一篇UIScrollView简介：UIScrollView简介

首先看一下效果图：


   


代码如下：

#import "ViewController.h"

#define KWidth 320
#define KHeight 180

@interface ViewController ()<UIScrollViewDelegate>

@property (nonatomic, strong) UIScrollView *scrollView;
@property (nonatomic, weak) UIPageControl *pageControl;
@property (nonatomic, strong) NSTimer *timer;
@property (nonatomic, strong) NSArray *imageArray;

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];

//初始化图片数组，展示4张图片（ABCD），首尾多添加2张（DABCDA）
self.imageArray = @[@"04.jpg", @"01.jpg", @"02.jpg", @"03.jpg", @"04.jpg", @"01.jpg"];

//创建scrollView
[self createScrollView];

//创建pageControl
[self createPageControl];

//创建定时器
[self createNSTimer];
}

- (void)createScrollView
{
//初始化
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(28, 50, KWidth, KHeight)];
//循环添加图片
for (int i = 0; i < _imageArray.count; i++) {
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(KWidth * i, 0, KWidth, KHeight)];
imageView.image = [UIImage imageNamed:_imageArray[i]];
[scrollView addSubview:imageView];
}
//设置可以滚动的区域
scrollView.contentSize = CGSizeMake(KWidth * _imageArray.count, 0);
//设置当前位置，图片应为第二张
scrollView.contentOffset = CGPointMake(KWidth, 0);
//设置代理
scrollView.delegate = self;
//整页翻动
scrollView.pagingEnabled = YES;
//隐藏水平方向滚动条
scrollView.showsHorizontalScrollIndicator = NO;

[self.view addSubview:scrollView];
self.scrollView = scrollView;
}

- (void)createPageControl
{
//初始化
UIPageControl *pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(0, 0, 80, 30)];
//中心位置
pageControl.center = CGPointMake([UIScreen mainScreen].bounds.size.width * 0.5, CGRectGetMaxY(self.scrollView.frame) - 10);
//总页数
pageControl.numberOfPages = 4;
//当前页
pageControl.currentPage = 0;
//取消交互
pageControl.userInteractionEnabled = NO;

[self.view addSubview:pageControl];
self.pageControl = pageControl;
}

- (void)createNSTimer
{
self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(nextPage) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}

- (void)nextPage
{
NSInteger currentPage = self.pageControl.currentPage;
currentPage++;
if (currentPage == 5) {
currentPage = 0;
}
[self.scrollView setContentOffset:CGPointMake((currentPage + 1) * KWidth, 0) animated:YES];
}

#pragma mark - UIScrollViewDelegate
//滚动时调用
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
int index = scrollView.contentOffset.x / KWidth + 0.5;

if (index > 0 && index < 5) {
_pageControl.currentPage = index - 1;

}else if (scrollView.contentOffset.x == KWidth * 5) {
_pageControl.currentPage = 0;
scrollView.contentOffset = CGPointMake(KWidth, 0);

}else if (scrollView.contentOffset.x == 0) {
_pageControl.currentPage = 3;
scrollView.contentOffset = CGPointMake(KWidth * 4, 0);
}
}
//开始拖拽视图调用
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
[self.timer invalidate];
self.timer = nil;
}
//完成拖拽调用
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
[self createNSTimer];
}