我想用核心数据在swift中制作Transformable图像。 我创建了可变形的imageA。 当我试图看到数据库中是否有图像时,它告诉我们这里没有任何东西。 如何将图像添加到数据库?我的代码有什么问题? 这里是我的代码如何在swift中制作Transformable图像?
我使用方法setImage 和getImage的地方保存和获取适用于@NSManaged var isSet:NSNumber?
extension AppSettings {
@NSManaged var isSet: NSNumber?
@NSManaged var imageA: UIImage?
}
func setImage(inputAppSettings : AppSettings)
{
let theImage = UIImage(named: "image.png")
inputAppSettings.imageA = theImage
}
func getImage(inputAppSettings : AppSettings)
{
if let theImage = inputAppSettings.imageA
{
print("theImage: \(theImage)")
}
}
类MyTransformer:NSValueTransformer {
override class func allowsReverseTransformation() -> Bool
{
return true
}
class func transformedValue(value:AnyObject) -> AnyObject
{
var returnData:AnyObject = NSData()
let theImage = value as! UIImage
if let theData = UIImagePNGRepresentation(theImage)
{returnData = theData}
return returnData
}
class func reverseTransformedValue(value:AnyObject) -> AnyObject
{
var returnImage:AnyObject = UIImage()
let theData = value as! NSData
if let theImage = UIImage(data: theData)
{returnImage = theImage}
return returnImage
}
override class func transformedValueClass() -> AnyClass
{
return UIImage.self
}
}
func set()
{
if let moc = self.managedObjectContext {
let theAppSettingsAnyObject = NSEntityDescription.insertNewObjectForEntityForName("AppSettings", inManagedObjectContext: moc)
if let theAppSettings = theAppSettingsAnyObject as? AppSettings
{
theAppSettings.isSet = true
self.setImage(theAppSettings)
}
var savingError: NSError?
do {
try moc.save()
} catch let error1 as NSError {
savingError = error1
if let error = savingError{
print("Failed to save . Error = \(error)")
}
}
}
}
谢谢你的回答。但在小图像的情况下,只有一个图像来存储它,我认为如果我将使用转换,则代码会更少,所以我仍然需要这种方式。 – user