研究了两天半时间，新手无奈啊，话不多说，直接上代码。
#import "TestViewController.h"
#define s_x [UIScreen mainScreen].bounds.size.width
#define s_y [UIScreen mainScreen].bounds.size.height
NSArray * imagearr;
NSTimer * timer;
int _currentImageIndex;
@interface TestViewController ()<UIScrollViewDelegate>
@property (nonatomic,retain)UIScrollView * scv;
@property (nonatomic,retain)UIPageControl * page;
@property (nonatomic,retain)UIImageView * leftimageview;
@property (nonatomic,retain)UIImageView * centerimageview;
@property (nonatomic,retain)UIImageView * rightimageview;
@end
@implementation TestViewController
- (void)viewDidLoad {
[superviewDidLoad];
// Do any additional setup after loading the view.
self.view.backgroundColor=[UIColorwhiteColor];
imagearr=@[@"0.jpg",@"1.jpg",@"2.jpg",@"3.jpg",@"4.jpg",@"5.jpg"];
[selfmainView];
[selfsetimageview];
[selfsetDefaultImage];
[selfsettimer];
}
-(void)settimer{
timer=[NSTimerscheduledTimerWithTimeInterval:3target:selfselector:@selector(timechanged)userInfo:nilrepeats:YES];
NSLog(@"定时器启动");
[[NSRunLoopcurrentRunLoop]addTimer:timerforMode:NSRunLoopCommonModes];
}
-(void)timechanged{
int leftimageindex,rightimageindex;
CGPoint offset=[_scvcontentOffset];//内容视图的位置
//滑动发生后，实时变化图片加载，所以最先考虑的是图片的索引变化
_currentImageIndex=(_currentImageIndex +1 )%imagearr.count;
_centerimageview.image=[UIImageimageNamed:[NSStringstringWithFormat:@"%d.jpg",_currentImageIndex]];
//重新设置左右图片
leftimageindex=(_currentImageIndex+imagearr.count-1)%imagearr.count;
rightimageindex=(_currentImageIndex +1)%imagearr.count;
_leftimageview.image=[UIImageimageNamed:[NSStringstringWithFormat:@"%d.jpg",leftimageindex]];
_rightimageview.image=[UIImageimageNamed:[NSStringstringWithFormat:@"%d.jpg",rightimageindex]];
_page.currentPage=_currentImageIndex;
[_scvsetContentOffset:CGPointMake(s_x,0)animated:YES];
}
#pragma mark 添加控件scroll和pagecontrol
-(void)mainView{
_scv=[[UIScrollViewalloc]init];
_scv.frame=CGRectMake(0,0,s_x,s_y);
_scv.contentSize=CGSizeMake(s_x * imagearr.count,0);
//设置默认显示为s_x的地段，为默认centerimageview的位置
[_scvsetContentOffset:CGPointMake(s_x,0)];
//取消显示侧边滑动条
_scv.showsHorizontalScrollIndicator=NO;
_scv.showsVerticalScrollIndicator=NO;
//设置整页滑动
_scv.pagingEnabled=YES;
//设置回弹
_scv.bounces=YES;
_scv.delegate=self;
[self.viewaddSubview:_scv];
_page=[UIPageControlnew];
_page.currentPage=0;
_page.numberOfPages=imagearr.count;
_page.center=CGPointMake(s_x/2,s_y-100);
_page.pageIndicatorTintColor=[UIColorcolorWithRed:0.021green:1.000blue:0.146alpha:1.000];
[self.viewaddSubview:_page];
}
#pragma mark 设置imageview控件
-(void)setimageview{
_leftimageview=[UIImageViewnew];
_leftimageview.frame=CGRectMake(0,0,s_x,s_y);
_leftimageview.backgroundColor=[UIColorgreenColor];
_leftimageview.contentMode=UIViewContentModeScaleAspectFill;
[_scvaddSubview:_leftimageview];
_centerimageview=[UIImageViewnew];
_centerimageview.frame=CGRectMake(s_x,0,s_x,s_y);
_centerimageview.backgroundColor=[UIColorcolorWithRed:1.000green:0.453blue:0.688alpha:1.000];
_centerimageview.contentMode=UIViewContentModeScaleAspectFill;
[_scvaddSubview:_centerimageview];
_rightimageview=[UIImageViewnew];
_rightimageview.frame=CGRectMake(2*s_x,0,s_x,s_y);
_rightimageview.backgroundColor=[UIColororangeColor];
_rightimageview.contentMode=UIViewContentModeScaleAspectFill;
[_scvaddSubview:_rightimageview];
}
#pragma mark 设置默认显示图片
-(void)setDefaultImage{
_leftimageview.image=[UIImageimageNamed:imagearr[imagearr.count-1]];//左边显示最后一张、
_centerimageview.image=[UIImageimageNamed:imagearr[0]];
_rightimageview.image=[UIImageimageNamed:imagearr[1]];
_currentImageIndex=0;
_page.currentPage=_currentImageIndex;
}
#pragma mark 根据滑动的方向来判定图片如何加载
-(void)ReloadImage{
int leftimageindex,rightimageindex;
CGPoint offset=[_scvcontentOffset];//内容视图的位置
if (offset.x>s_x) {//右滑
//滑动发生后，实时变化图片加载，所以最先考虑的是图片的索引变化
_currentImageIndex=(_currentImageIndex +1 )%imagearr.count;
}
if (offset.x<s_x) {//左滑
/* ******************************************这个判断是重点 */
_currentImageIndex=(_currentImageIndex +(imagearr.count-1))%imagearr.count;
}
_centerimageview.image=[UIImageimageNamed:[NSStringstringWithFormat:@"%d.jpg",_currentImageIndex]];
//重新设置左右图片
leftimageindex=(_currentImageIndex+imagearr.count-1)%imagearr.count;
rightimageindex=(_currentImageIndex +1)%imagearr.count;
_leftimageview.image=[UIImageimageNamed:[NSStringstringWithFormat:@"%d.jpg",leftimageindex]];
_rightimageview.image=[UIImageimageNamed:[NSStringstringWithFormat:@"%d.jpg",rightimageindex]];
}
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
//调用重新加载图片的方法
[selfReloadImage];
//移动到中间
[_scvsetContentOffset:CGPointMake(s_x,0)];
_page.currentPage=_currentImageIndex;
}
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
NSLog(@"开始拖动");
[timerinvalidate];
}
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
NSLog(@"拖动结束");
[selfsettimer];
}
这样就可以实现 当点击拖动图片时，计时器会停止计时，待拖动结束后，计时器重新计时。
原理：3个imageview位置不变，始终显示中间的centerimageview，而left和right始终预先计算并加载要显示的图片。这样拖动时会实现循环效果，而计时器那边也是如此
其他的例如从网络获取图片，图片点击事件等等，还没写，不过都是很简单的东西，希望对各位有帮助，这段代码拿过去直接就能用