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我正在尝试使用 NSCoding 和 NSKeyedArchiver 将图像保存到我的 Documents 文件夹中。该应用程序的工作原理如下：用户拍照，查看预览，保存图像，然后可以在图库部分查看图像。我不会同时保存多个图像。

我遇到了崩溃，不知道我是否错误地存档了图像，我的照片类设置是否不正确，或者我的取消存档代码是否错误。最终我需要抓取对象并使用它们来填充集合视图。

当我调用代码来加载对象时，我遇到了一个看起来像这样的崩溃

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ImageForArchiving countByEnumeratingWithState:objects:count:]: unrecognized selector sent to instance 0x174232da0' *** First throw call stack: (0x18533c22c 0x196fb00e4 0x1853432f4 0x1853400a8 0x18524296c 0x10001aefc 0x189ded1ec 0x189dd62c8 0x189decb88 0x189dec814 0x189de5d50 0x189db8f74 0x18a05a124 0x189db7488 0x1852f3f8c 0x1852f3230 0x1852f12e0 0x18521cf74 0x18ec7f6fc 0x189e1ed94 0x10001840c 0x19765aa08) libc++abi.dylib: terminating with uncaught exception of type NSException

我的子类代码如下所示。ImageForArchiving 符合 NSCoder 协议。

ImageForArchiving.h

    @interface ImageForArchiving : NSObject <NSCoding>

@property (strong) NSDate *date;
@property (strong) NSData *imageData;

+ (ImageForArchiving *)createImageWithImage:(NSData*)data andDate:(NSDate*)date;
-(void)encodeWithCoder:(NSCoder *)aCoder;
-(id)initWithCoder:(NSCoder *)aDecoder;

@结尾

ImageForArchiving.m

@implementation ImageForArchiving

+ (ImageForArchiving *)createImageWithImage:(NSData*)data andDate:(NSDate*)date {

    ImageForArchiving *archiveImage = [[ImageForArchiving alloc] init];

    [archiveImage setDate:date];
    [archiveImage setImageData:data];

    return archiveImage;
}

- (id) initWithCoder: (NSCoder *)coder
{
    if (self = [super init])
    {
        [self setDate: [coder decodeObjectForKey:@"date"]];
        [self setImageData: [coder decodeObjectForKey:@"image"]];

    }
    return self;
}

- (void) encodeWithCoder: (NSCoder *)coder
{

    [coder encodeObject:self.date forKey:@"date"];
    [coder encodeObject:self.imageData forKey:@"image"];

}

@end

存档代码在预览 VC 中，用户可以在拍摄后查看照片。它显示为从带有块的 segue 中弹出的模式。

PreviewViewController.m （保存图像 IBAction）

NSString *filePath = [self createPathForDataFile];
    NSData *pngData = UIImagePNGRepresentation(self.previewImage.image);
    NSDate *date = [NSDate date];

    ImageForArchiving *imageRecord = [ImageForArchiving createImageWithImage:pngData andDate:date];
    [self saveItemsAtFilePath:filePath andImageToArchive:imageRecord];

创建文件路径

- (NSString *)createPathForDataFile
{
    NSFileManager *fileManager = [NSFileManager defaultManager];

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsPath = [paths objectAtIndex:0];


    documentsPath = [documentsPath stringByExpandingTildeInPath];
    NSError *error = nil;
    if ([fileManager fileExistsAtPath: documentsPath] == NO)
    {
        [fileManager createDirectoryAtPath:documentsPath withIntermediateDirectories:YES attributes:nil error:&error];
    }

    return [documentsPath stringByAppendingPathComponent:@"images"];
}

保存图像

- (void)saveItemsAtFilePath:(NSString*)filePath andImageToArchive:(ImageForArchiving*)imageRecord {

        [NSKeyedArchiver archiveRootObject:imageRecord toFile:filePath];
    }

加载图像 - 这是发生崩溃的地方

- (void)loadItems {
    NSString *filePath = [self createPathForDataFile];

    if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
        self.galleryItemsArray = [NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
    } else {
        self.galleryItemsArray = [NSMutableArray array];
    }
}
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