iOS - 组图放大查看

是个新页面，点击数组中某张图片，进入此页面：
.h文件：

#import <UIKit/UIKit.h>

@protocol ShowImgViewControllerDelegate <NSObject>

- (void)getDeleteAry:(NSMutableArray *)deleteAry;

@end

@interface ShowImgViewController : UIViewController
// 图片数组
@property (nonatomic,strong) NSMutableArray *dataSource;
// 从外界进入点击的图片坐标（第x张图片）
@property (nonatomic,assign) NSInteger index;
// 是否可删除
@property (nonatomic,assign) BOOL canDelete;
// 删除的图片数组
@property (nonatomic,strong) NSMutableArray *deleteAry;

// 代理
@property (nonatomic,weak) id<ShowImgViewControllerDelegate> delegate;
@end

.m

#import "ShowImgViewController.h"

#define K_SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width// 屏宽
#define K_SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height// 屏高
#define kGetNavAndStatusHeight  (self.navigationController.navigationBar.frame.size.height+[[UIApplication sharedApplication] statusBarFrame].size.height)// 状态栏+导航栏高度

@interface ShowImgViewController ()<UIScrollViewDelegate,UIGestureRecognizerDelegate>
@property (nonatomic, strong) UIScrollView * scrollView;
@end

@implementation ShowImgViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    // 删除的图片放入此数组
    self.deleteAry = [@[] mutableCopy];
    [self.view addSubview:self.scrollView];

    // 标题展示当前图片位置，如：3/6
    self.title = [NSString stringWithFormat:@"%ld/%lu",self.index+1,(unsigned long)self.dataSource.count];

    // 展示图片
    [self setUpImageView];

    if (self.canDelete) {
        // 可删除
        UIButton *RightBtn = [UIButton buttonWithType:UIButtonTypeCustom];
        RightBtn.frame = CGRectMake(0, 0, 40, 40);
        [RightBtn setImage:[UIImage imageNamed:@"删除-1"] forState:0];
        RightBtn.imageEdgeInsets = UIEdgeInsetsMake(10, 10, 10, 10);
        [RightBtn addTarget:self action:@selector(deleteAction) forControlEvents:UIControlEventTouchUpInside];
        UIBarButtonItem *item = [[UIBarButtonItem alloc]initWithCustomView:RightBtn];
        self.navigationItem.rightBarButtonItem = item;
    }

}


- (void)viewWillDisappear:(BOOL)animated{

    [super viewWillDisappear:animated];
    if (self.delegate && [self.delegate respondsToSelector:@selector(getDeleteAry:)]) {
        // 上级页面获取到删除的图片坐标
        [self.delegate getDeleteAry:self.deleteAry];
    }
}


#pragma mark - 布局
- (UIScrollView *)scrollView
{
    if (!_scrollView) {
        self.scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, K_SCREEN_WIDTH, K_SCREEN_HEIGHT)];
        _scrollView.backgroundColor = [UIColor blackColor];
        _scrollView.delegate = self;
        //这里
        _scrollView.contentSize = CGSizeMake(K_SCREEN_WIDTH* self.dataSource.count, K_SCREEN_HEIGHT - kGetNavAndStatusHeight);
        _scrollView.contentOffset = CGPointMake(K_SCREEN_WIDTH * self.index, 0);
        _scrollView.scrollEnabled = YES;
        _scrollView.pagingEnabled = YES;
        _scrollView.userInteractionEnabled = YES;

    }
    return _scrollView;
}


-(void)setUpImageView
{
    for (UIView *views in [self.scrollView subviews]) {
        [views removeFromSuperview];
    }
    int index = 0;
    for (int i = 0;i < self.dataSource.count;i++)
    {
        UIImageView * imageView = [[UIImageView alloc]init];
        imageView.frame = CGRectMake(K_SCREEN_WIDTH * i, 0, K_SCREEN_WIDTH, K_SCREEN_HEIGHT);

        UIImage *chooseImg = self.dataSource[i];
        imageView.image = chooseImg;
        CGFloat imgH = chooseImg.size.height/chooseImg.size.width*K_SCREEN_WIDTH;
        if (imgH > KscreenHeight) {
            imgH = KscreenHeight;
        }
        imageView.bounds = CGRectMake(0, 0, K_SCREEN_WIDTH, imgH);

        imageView.center = CGPointMake(K_SCREEN_WIDTH/2.0 + K_SCREEN_WIDTH * i, K_SCREEN_HEIGHT/2.0 - kGetNavAndStatusHeight/2);
        imageView.tag = index;
        [self.scrollView addSubview:imageView];
        index ++;
    }
}

#pragma mark - UIScrollViewDelegate
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    NSInteger index = scrollView.contentOffset.x/K_SCREEN_WIDTH;
    self.index = index;

    self.title = [NSString stringWithFormat:@"%ld/%lu",self.index+1,(unsigned long)self.dataSource.count];
}

#pragma mark - 删除
- (void)deleteAction{

    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"确认要删除吗" message:@"" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"确定", nil];
    alert.tag = 100;
    [alert show];

}


-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{

    if (buttonIndex == 1) {

        if (alertView.tag == 100) {
            // 删除
            if (self.dataSource.count > self.index) {
                [self.deleteAry addObject:[NSString stringWithFormat:@"%ld",(long)self.index]];
                [self.dataSource removeObjectAtIndex:self.index];
                if (self.index > 0) {
                    self.index = self.index - 1;
                }
                self.scrollView.contentSize = CGSizeMake(K_SCREEN_WIDTH* self.dataSource.count, K_SCREEN_HEIGHT - kGetNavAndStatusHeight);
                self.scrollView.contentOffset = CGPointMake(K_SCREEN_WIDTH * self.index, 0);
                [self setUpImageView];
                self.title = [NSString stringWithFormat:@"%ld/%lu",self.index+1,(unsigned long)self.dataSource.count];

            }
        }else if (alertView.tag == 200){
            // 保存

            if (self.dataSource.count > self.index) {
                UIImage *img = self.dataSource[self.index];
                // 改为png格式
                NSData* imageData =  UIImagePNGRepresentation(img);
                UIImage* newImage = [UIImage imageWithData:imageData];
                if (img != nil) {
                    UIImageWriteToSavedPhotosAlbum(newImage, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
                }
            }

        }

    }

}


#pragma mark - 长按保存
- (void)longPressAction:(UIGestureRecognizer *)gesture{

    if (gesture.state == UIGestureRecognizerStateBegan){

        // 获取点击的图片view
        UIImageView *imageView = (UIImageView *)gesture.self.view;
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"保存图片至本地吗" message:@"" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"确定", nil];
        alert.tag = 200;
        [alert show];
    }

}

//  <保存到相册>
-(void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
    NSString *msg = nil ;
    if(error){
        NSLog(@"保存失败");
    }else{
        NSLog(@"保存成功");
    }
}

使用保存图片至本地的功能时，别忘了在plist文件中添加NSPhotoLibraryAddUsageDescription属性~~