iOS之OC源码，相册循环查看功能的实现-创新互联

#import "ViewController.h"

#import "YZUIScrollView.h"

#define kuan ([UIScreen mainScreen].bounds.size.width+20)

#define gao [UIScreen mainScreen].bounds.size.height

@interface ViewController ()

@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

  _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

//第二个类

#import "YZUIScrollView.h"

@interface YZUIScrollView ()

@property(nonatomic,strong)UIImageView *imageview;

@property(nonatomic,strong)UIImage *image;//内容视图的图片

@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

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