您可以在核心数据中保存一系列图像吗? [英] Can you save an array of images in core data?

问题描述

我知道您可以使用实体的二进制数据属性保存一个，但是是否可以保存多个?

I know you can save one by using the binary data property of an entity but is it possible to save multiple?

您可以使用以下方法保存一个:

you can save one by using this:

UIImageJPEGRepresentation(image: UIImage)

您可以保存它，然后使用

you can save it and then transform it into an image again with

UIImage(data: ____)

但是我可以将充满图像的数组转换为二进制数据吗?

but can I transform an array full of images into binary data?

如果您不能使用核心数据，我还有其他方法可以做到吗?

If you can't with core data, any other ways I can do it?

顺便说一句，图像阵列中充满了用户保存在设备上的图像.

BTW, the image array is full of user taken image saved on the device..

感谢所有帮手！

推荐答案

将数组转换为NSMutableArray并将其归档为NSData

convert your array to NSMutableArray and archive it as NSData

var imgArray = [UIImage]();

var CDataArray = NSMutableArray();

for img in imgArray{
    let data : NSData = NSData(data: UIImagePNGRepresentation(img))
    CDataArray.addObject(data);
}

//convert the Array to NSData
//you can save this in core data
var coreDataObject = NSKeyedArchiver.archivedDataWithRootObject(CDataArray);

从CData中提取后，提取数据:

after pulling from CData, extract data:

//extract:
if let mySavedData = NSKeyedUnarchiver.unarchiveObjectWithData(coreDataObject) as? NSArray{
    //extract data..
}

雨燕5

现在不建议使用某些方法.以下代码可在Swift 5中运行:

Swift 5

There are some methods deprecated now. The following code is working in Swift 5:

func coreDataObjectFromImages(images: [UIImage]) -> Data? {
    let dataArray = NSMutableArray()
    
    for img in images {
        if let data = img.pngData() {
            dataArray.add(data)
        }
    }
    
    return try? NSKeyedArchiver.archivedData(withRootObject: dataArray, requiringSecureCoding: true)
}

func imagesFromCoreData(object: Data?) -> [UIImage]? {
    var retVal = [UIImage]()

    guard let object = object else { return nil }
    if let dataArray = try? NSKeyedUnarchiver.unarchivedObject(ofClass: NSArray.self, from: object) {
        for data in dataArray {
            if let data = data as? Data, let image = UIImage(data: data) {
                retVal.append(image)
            }
        }
    }
    
    return retVal
}

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