UICollectionView PrepareForSegue 图像未传输

Question

我有一个 UICollectionView，我无法将图像传输到详细视图。当我使用本地图像和带有 [pictures[row]] 方法的图片数组时，detailview 传输将起作用，但由于使用 SDWebImage 框架，我不能这样做。选择单元格后，我无法确定将图像正确传输到详细视图。逻辑在第一个方法 CellForItemAtIndexPath 中解释。选定的单元格和为 segue 方法做准备是导致问题的原因。如果您需要更多信息，请告诉我。

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{

    pictureViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"MyCell" forIndexPath:indexPath];

    NSString *pictures1 = [[pictures objectAtIndex:indexPath.row]objectForKey:@"filename"];
    comment = [[pictures objectAtIndex:indexPath.row] objectForKey:@"comment"];

    [cell.imageView setImageWithURL:[NSURL URLWithString:pictures1]
                    placeholderImage:[UIImage imageNamed:@"Earth.png"]
    completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType)
     {
         NSLog(@"Error downloaidng images");
     }];


   // UIImage *image;

   // int row = [indexPath row];

    //image = [UIImage imageNamed:pictures[row]];

    //image = [UIImage imageWithData:imageUrl];

   // cell.imageView.image = image;

    return cell;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{

    UIImage *image;

    //int row = [indexPath row];

    NSString *pictures1 = [[pictures objectAtIndex:indexPath.row]objectForKey:@"filename"];
   // image = [UIImage imageNamed:pictures[row]];

    image = [UIImage imageNamed:pictures1];

    pictureDetailView *pictureDetail = [[pictureDetailView alloc]init];
    pictureDetail.image = image;

}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(UICollectionViewCell *)sender
{
    pictureDetailView *targetVC = (pictureDetailView *) [segue destinationViewController];
    NSIndexPath *indexPath = [self.collectionView indexPathForCell:sender];

    UIImage *image;

    //int row = [indexPath row];


    NSString *pictures1 = [[pictures objectAtIndex:indexPath.row]objectForKey:@"filename"];


   // image = [UIImage imageNamed:pictures[row]];

    image = [UIImage imageNamed:pictures1];

    //image = [UIImage imageWithData:imageUrl];

    targetVC.image=image;
}




@end

Answer 1

我在正在开发的应用程序中遇到了类似的问题，但找不到任何有关 Collection Views 的帮助。我使用的代码如下（已更新以匹配您的方法）。我希望这可以帮助您走上正轨。您还可以查看SDWebImage GitHub page 上发布的演示项目。这帮助我解决了其中一些问题。

在您的 CollectionViewController.h 中：

#import <UIKit/UIKit.h>
#import "PictureDetailView.h"

@class PictureDetailView;

@interface CollectionViewController : UICollectionViewController <UICollectionViewDataSource, UICollectionViewDelegate>

@property (nonatomic, strong) PictureDetailView *detailViewController;

@end

在您的 CollectionViewController.m 中：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"yourSegueNameHere"]) {
        PictureDetailView *pictureDetail = segue.destinationViewController;
        NSIndexPath *indexPath = [[self.collectionView indexPathsForSelectedItems] lastObject];
        NSString *largeImageURL = [pictures1 objectAtIndex:indexPath.row];
        pictureDetail.imageURL = [NSURL URLWithString:largeImageURL];
    }
}

在您的 DetailViewController.h 中

#import <UIKit/UIKit.h>
#import "CollectionViewController.h"

@interface DetailViewController : UIViewController 

@property (strong, nonatomic) IBOutlet UIImageView *imageView;
@property (strong, nonatomic) NSURL *imageURL;

@end

在您的 DetailViewController.m 中

#import "DetailViewController.h"
#import <SDWebImage/UIImageView+WebCache.h>
#import "UIImageView+WebCache.h"

@interface DetailViewController ()

@end

@implementation DetailViewController

@synthesize imageURL = _imageURL;
@synthesize imageView = _imageView;


- (void)setImageURL:(NSURL *)imageURL
{
    if (_imageURL != imageURL)
    {
        _imageURL = imageURL;
        [self configureView];
    }
}

- (void)configureView
{
    if (self.imageURL)
    {
        [self.imageView setImageWithURL:self.imageURL
                       placeholderImage:nil
                        options:SDWebImageProgressiveDownload
                        completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType)
         {
         }];
    }
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self configureView];
}

Answer 2

只需访问所选单元格的imageView 并提取其图像。操作方法如下：

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [self collectionView:collectionView cellForItemAtIndexPath:indexPath];
    UIImage *image = cell.imageView.image;

    // Pass the image to the next VC.
}

如果您需要更多帮助，请告诉我。