iOS 图片轮播图（自动滚动）
#import "DDViewController.h"
#define DDImageCount 5
@interface DDViewController ()<UIScrollViewDelegate>
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;
//定时器
@property (nonatomic,strong)NSTimer *timer;
@end
@implementation DDViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// 设置一些固定的尺寸参数
CGFloat imageW = self.scrollView.frame.size.width;
CGFloat imageH = self.scrollView.frame.size.height;
CGFloat imageY = 0;
// 1.添加5张图片到scrollview中
for (int i=0; i<DDImageCount; i++) {
UIImageView *imageView = [[UIImageView alloc]init];
CGFloat imageX = i * imageW;
imageView.frame = CGRectMake(imageX, imageY, imageW, imageH);
imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"img_0%d",i+1]];
[self.scrollView addSubview:imageView];
}
// 2.设置内容尺寸
CGFloat contenW = DDImageCount * imageW;
// 水平滚动
self.scrollView.contentSize = CGSizeMake(contenW, 0);
// 上下滚动
// self.scrollView.contentSize = CGSizeMake(0, XXXX);
// 3.隐藏水平滚动条
self.scrollView.showsHorizontalScrollIndicator = NO;
// 4.分页
self.scrollView.pagingEnabled = YES;
// 5.设置pagecontrol的总页数
self.pageControl.numberOfPages = DDImageCount;
// 6.添加定时器（每隔2秒调用一次self 的 nextImage的方法）
[self addTimer];
}
//添加定时器
- (void)addTimer
{
self.timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextImage) userInfo:nil repeats:YES];
// 设置主线程。
[[NSRunLoop currentRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}
//移除定时器
- (void)removertimer
{
[self.timer invalidate];
self.timer = nil;
}
- (void)nextImage
{
// 增加pagecontrol的页码
int page = 0;
if (self.pageControl.currentPage == DDImageCount - 1) {
page = 0;
}else{
page = self.pageControl.currentPage + 1;
}
// 计算scrollview滚动位置
CGFloat offsetX = page * self.scrollView.frame.size.width;
CGPoint offset = CGPointMake(offsetX, 0);
[self.scrollView setContentOffset:offset animated:YES];
}
//ScrollView代理方法。使用时要设置代理（self.delgate = self）或者在图片上进行设置
/**
* 当scrollView正在滚动就会调用
*/
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
// 根据scrollview的滚动位置决定pagecontrol显示第几页
CGFloat scrollW = scrollView.frame.size.width;
int page = (scrollView.contentOffset.x + scrollW * 0.5) / scrollW;
self.pageControl.currentPage = page;
}
/**
* 开始拖拽的时候调用
*/
- (void) scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
// 停止定时器(一旦定时器停止了,就不能再使用)
[self removertimer];
}
/**
* 停止拖拽的时候调用
*/
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
//开启定时器
[self addTimer];
}