Question

我有代码可以通过相机或手机画廊拍照，但是我想将图像保存在我觉得很难的核心数据中。我读了很多关于它的内容，我不确定图像是字符串还是二进制数据以及如何保存它以及如何获得它。

@property (strong) NSMutableArray *allPic;
@property (strong) NSManagedObject *Image;
@end
@implementation ViewController



-(NSManagedObjectContext *)managedObjectContext
{
    NSManagedObjectContext *context = nil;
    id delegate = [[UIApplication sharedApplication] delegate];
    if ([delegate performSelector:@selector(managedObjectContext)]) {
        context = [delegate managedObjectContext];
    }
    return context;
}
-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    // Fetch the devices from persistent data store
    NSManagedObjectContext *managedObjectContext = [self     managedObjectContext];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Picture"];
    self.allPic = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];
}


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

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)takePic:(id)sender {

    // ALERT SHEET.
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];

    //CAMERA
    UIAlertAction *openCamrea = [UIAlertAction actionWithTitle:@"צלם" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
    {
        // If device has no camera.
        if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
        {
            UIAlertController *alertNoCamera = [UIAlertController alertControllerWithTitle:@"Error" message:@"Device has no camera" preferredStyle:UIAlertControllerStyleAlert];
            UIAlertAction *ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action){}];
            [alertNoCamera addAction:ok];
            [self presentViewController:alertNoCamera animated:YES completion:nil];
        }
        else// if  have a camera.
        {
           UIImagePickerController *picker = [[UIImagePickerController alloc] init];
           picker.delegate = self;
           picker.allowsEditing = YES;
           picker.sourceType = UIImagePickerControllerSourceTypeCamera;


           [self presentViewController:picker animated:YES completion:NULL];
        }
    }];
    // GALLERY
    UIAlertAction *openGallery = [UIAlertAction actionWithTitle:@"גלריה" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
    {
        UIImagePickerController *picker = [[UIImagePickerController alloc] init];
        picker.delegate = self;
        picker.allowsEditing = YES;
        picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

        [self presentViewController:picker animated:YES completion:NULL];
    }];

    [alert addAction:openCamrea];
    [alert addAction:openGallery];
    [self presentViewController:alert animated:YES completion:nil];
}

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
     //save image

{

Answer 1

我认为正确的方法是将目录中的文件保存并存储到CoreData的路径。以下是我如何实现它：

{{1}}

Answer 2

要在核心数据中保存图像：

您可以使用二进制数据属性类型将图像存储在Core Data中。但是你应该知道一些事情：

始终将您的UIImage转换为便携式数据格式，例如png或jpg，例如：

<meta charset="utf-8">...

在此属性

上启用“允许外部存储”

JS Fiddle 2

核心数据会在达到某个阈值时将数据移动到外部文件。此文件也完全由Core Data管理，因此您不必担心它。

如果遇到性能问题，请尝试将二进制数据属性移动到单独的实体。

您应该将转化抽象为NSData *imageData = UIImagePNGRepresentation(image);子类界面后面的NSData，这样您就不必担心从NSManagedObject到UIImage的转换反之亦然。

如果您的图片与模型中的实体没有很强的相关性，我建议将它们存储在Core Data之外。

从图库或相机拍摄图像：

NSData

希望这有帮助。

从相机/图库中拍摄照片并将其保存在核心数据中

2 个答案: