iOS源码之OC相册，可以循环查看图片

#import "ViewController.h"
#import "YZUIScrollView.h"
#define kuan ([UIScreen mainScreen].bounds.size.width+20)
#define gao [UIScreen mainScreen].bounds.size.height
@interface ViewController ()<UIScrollViewDelegate>
@property (weak, nonatomic) IBOutlet UIScrollView *huaBu;
@property(nonatomic,strong)NSArray *images;
@property(nonatomic)NSInteger currentIndex;
@end@implementation ViewController
//懒加载,调用get方法时对属性进行初始化
-(NSArray *)images
{
if(_images==nil)
{
NSMutableArray *imagearray=[NSMutableArray array];
for (int i=1; i<7; i++) {
NSString *imageName=[NSString stringWithFormat:@"new_feature_%d",i];
UIImage *image=[UIImage imageNamed:imageName];
[imagearray addObject:image];
}
_images=imagearray;
}
return _images;
}
- (void)viewDidLoad {
[super viewDidLoad];
//设置UIScrollView的contentSize
_huaBu.contentSize=CGSizeMake(kuan*3, gao);
//设置分页
_huaBu.pagingEnabled=YES;
//隐藏水平滚动栏和垂直滚动栏
_huaBu.showsHorizontalScrollIndicator=NO;
_huaBu.showsVerticalScrollIndicator=NO;
//设置背景颜色,突出不同的图片
_huaBu.backgroundColor=[UIColor blackColor];
//设置代理要遵守协议<UIScrollViewDelegate>
_huaBu.delegate=self;
//调用方法添加子视图
[self tianJiaZiShiTu];
//调用方法添加图片
[self tianJiaTuPian];
}
//添加子视图的方法
-(void)tianJiaZiShiTu
{
//相册的话，是一个大的UIScrollView中放了很多的小UIScrollView，但是为了节省内存空间，所以只是添加了三个UIScrollView（图片不停的变换位置）
for (int i=0; i<3; i++) {
//创建YZUIScrollView
YZUIScrollView * yzuisv=[[YZUIScrollView alloc] initWithFrame:CGRectMake(kuan*i, 0, kuan-20, gao)];
//添加YZUIScrollView
[_huaBu addSubview:yzuisv];
//设置tag值，便于区分
yzuisv.tag=1000+i;
}
}
//添加方法的图片
-(void)tianJiaTuPian
{
YZUIScrollView *leftSC=(YZUIScrollView *)[_huaBu viewWithTag:1000];
YZUIScrollView *middleSC=(YZUIScrollView *)[_huaBu viewWithTag:1001];
YZUIScrollView *rightSC=(YZUIScrollView *)[_huaBu viewWithTag:1002];
leftSC.image=self.images[[self indexFofEnable:_currentIndex-1]];
middleSC.image=self.images[[self indexFofEnable:_currentIndex]];
rightSC.image=self.images[[self indexFofEnable:_currentIndex+1]];
//设置偏移量，这步很重要
_huaBu.contentOffset=CGPointMake(kuan, 0);
}
//确保索引可用
-(NSInteger)indexFofEnable:(NSInteger)index
{
if(index<0)
{
return self.images.count-1;
}
else if (index>self.images.count-1)
{
return 0;
}
else
return index;
}
//滚动结束后，把所有的缩放视图比例还原为1.0
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
for (id obj in _huaBu.subviews) {
if([obj isKindOfClass:[UIScrollView class]])
{
UIScrollView *scaleSC=(UIScrollView *)obj;
scaleSC.zoomScale=1.0;
}
}
//判断左右滑动
//偏移量的x为0，就是说明向右滑动了，就是看的之前左边的那张图片
if(scrollView.contentOffset.x==0)
{
//对应的图像应该是变成左边的图像
_currentIndex--;
}
//偏移量的x为两个屏幕的宽，就是说明向左滑动了，就是看的之前右边的那张图片
else if(scrollView.contentOffset.x== kuan*2)
{
//对应的图像应该是变成右边的图像
_currentIndex++;
}
_currentIndex=[self indexFofEnable:_currentIndex];
[self tianJiaTuPian];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}@end

#import "YZUIScrollView.h"@interface YZUIScrollView ()<UIScrollViewDelegate>

@property(nonatomic,strong)UIImageView *imageview;
@end@implementation YZUIScrollView-(instancetype)initWithFrame:(CGRect)frame
{
if(self =[super initWithFrame:frame])
{
//添加内容视图
UIImageView *imageview1=[[UIImageView alloc] initWithFrame:self.bounds];
[self addSubview:imageview1];
_imageview=imageview1;
//设置最大最小倍数和代理
self.minimumZoomScale=0.5;
self.maximumZoomScale=1.5;
self.delegate=self;
//双击事件
UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(shuangJi:)];
tap.numberOfTapsRequired=2;
[self addGestureRecognizer:tap];
}
return self;
}
-(void)shuangJi:(UITapGestureRecognizer *)tap
{
//当缩放比例不为1.0，还原缩放比例
if (self.zoomScale !=1.0) {
[self setZoomScale:1.0 animated:YES];
return ;
}
CGPoint location =[tap locationInView:self];
CGRect rect =CGRectMake(location.x-100, location.y-100,200,200);
[self zoomToRect:rect animated:YES];
}
//重写setImg方法
-(void)setImage:(UIImage *)image
{
//set本身的方法要完成的事必须完成
_image=image;
//设置内容视图的图片
_imageview.image=image;
}
//UIScrollViewDelegate代理方法
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return _imageview;
}
@end