我正在Swift 3 - xcode 8中进行一个项目，我正在尝试使用核心数据来保存并在数据库“用户”中显示一些图像。
此图片是他个人资料中的用户照片。
现在我已经设法保存字符串并从核心数据中显示它们，但是我在处理图像方面遇到了问题。
这是我到目前为止所做的：
将USERS添加到核心数据中
func addUser() {
let app = UIApplication.shared.delegate as! AppDelegate
let context = app.persistentContainer.viewContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
request.returnsObjectsAsFaults = false
let newUser = NSEntityDescription.insertNewObject(forEntityName: "Users", into: context)
if (firstName.text == "" && lastName.text == "" && contact.text == "" && email.text == "") { //if we have a user profile delete it
deleteUser()
} else { // add a new user profile
newUser.setValue(firstName.text, forKey: "firstName")
newUser.setValue(lastName.text, forKey: "lastName")
newUser.setValue(contact.text, forKey: "contact")
newUser.setValue(email.text, forKey: "email")
//newUser.setValue(imageView.image, forKey: "photo")
//let imgUrl = UIImagePickerControllerReferenceURL as! NSURL
let img = UIImage(named: "f.png")
let imgData = UIImageJPEGRepresentation(img!, 1)
newUser.setValue(imgData, forKey: "photo")
print ("Data added in Users")
}
do {
try context.save()
//print("saved!!!")
Alert.show(title: "Success", message: "Profile Saved", vc: self)
} catch {
// print ("Error")
Alert.show(title: "Error", message: "Profile not Saved", vc: self)
}
}
显示用户来自core data
func showUser() {
let app = UIApplication.shared.delegate as! AppDelegate
let context = app.persistentContainer.viewContext
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")
request.returnsObjectsAsFaults = false
do {
let results = try context.fetch(request)
if results.count > 0 {
print("Profile: Data Found:")
for result in results as! [NSManagedObject] {
if let firstNameinData = result.value(forKey: "firstName") as? String{
firstName.text = firstNameinData
print(firstNameinData)
}
if let lastNameinData = result.value(forKey: "lastName") as? String{
lastName.text = lastNameinData
print(lastNameinData)
}
if let contactinData = result.value(forKey: "contact") as? String{
contact.text = contactinData
print(contactinData)
}
if let emailinData = result.value(forKey: "email") as? String{
email.text = emailinData
print(emailinData)
}
if let photoinData = result.value(forKey: "photo") as? UIImage{
imageView.image = photoinData
}
}
} else { // if there is not a user profile
firstName.text = ""
lastName.text = ""
contact.text = ""
email.text = ""
print("Profile : No data found")
}
//print("Loaded!!!")
} catch {
print ("Error Loading")
}
}
我无法显示我保存的图像。 你有什么提示吗？
编辑：Xcode给我这条消息“资产连接中断或资产已经中断”
答案 0 :(得分：9)
photo的属性Users为(NS)Data，正如您所做的那样，转换
UIImage加入NSData。
let img = UIImage(named: "f.png")
let imgData = UIImageJPEGRepresentation(img!, 1)
newUser.setValue(imgData, forKey: "photo")
当您检索信息时，您就像photo是一个UIImage对象：
if let photoinData = result.value(forKey: "photo") as? UIImage{
imageView.image = photoinData
}
根据之前的行，这是不合逻辑的。它应该是这样的：
if let imageData = result.value(forKey: "photo") as? NSData {
if let image = UIImage(data:imageData) as? UIImage {
imageView.image = image
}
}
注意：我不会说Swift，所以建议的代码可能无法编译，但你应该知道什么是错的，需要做些什么。
答案 1 :(得分：1)
var results :[Any] = []
let image = UIImage(named: "image.png")
//this is the line that appears to be wrong
let imageData = UIImagePNGRepresentation(image!) as NSData?
guard let appDelegate =
UIApplication.shared.delegate as? AppDelegate else {
return
}
// 1
let managedContext =
appDelegate.persistentContainer.viewContext
// 2
let entity =
NSEntityDescription.entity(forEntityName: "Image",
in: managedContext)!
let person = NSManagedObject(entity: entity,
insertInto: managedContext)
// 3
person.setValue(imageData, forKeyPath: "name")
// 4
do {
try managedContext.save()
results.append(person)
} catch let error as NSError {
print("Could not save. \(error), \(error.userInfo)")
}
答案 2 :(得分：1)
Larme几乎可以看到，但不是这样：
if let image = UIImage(data:imageData) as? UIImage
这样做：
if let image = UIImage(data: imageData as Data)
答案 3 :(得分：1)
希望这会对您有所帮助。首先，我也很困惑将图像存储在核心数据中。
这用于将图像保存在coreData中
首先创建Nsmanaged对象类
class Item: NSManagedObject {
}
Declare the image as NSData
import CoreData
extension Item {
@NSManaged var image: NSData?
@NSManaged var name: String?
@NSManaged var email: String?
}
现在转到要保存图像的View Controller。
class newViewController: UIViewController ,UIImagePickerControllerDelegate,UINavigationControllerDelegate{
var item : Item? = nil
var imagePicker = UIImagePickerController()
var PassImages = UIImage()
@IBOutlet var name: UITextField!
@IBOutlet var email: UITextField!
@IBOutlet var photoclick: UIButton!
var context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
@IBAction func clickaction(_ sender: Any) {
if UIImagePickerController.isSourceTypeAvailable(UIImagePickerController.SourceType.photoLibrary){
print("Button capture")
let picker = UIImagePickerController()
picker.allowsEditing = true
picker.sourceType = .photoLibrary
picker.delegate = self //Don't forget this line!
self.present(picker, animated: true, completion: nil)
}
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
var selectedImage: UIImage?
if let editedImage = info[.editedImage] as? UIImage {
selectedImage = editedImage
self.image.image = selectedImage!
picker.dismiss(animated: true, completion: nil)
} else if let originalImage = info[.originalImage] as? UIImage {
selectedImage = originalImage
self.image.image = selectedImage!
picker.dismiss(animated: true, completion: nil)
}
}
func imagePickerControllerDidCancel(picker: UIImagePickerController!) {
self.dismiss(animated: true, completion: nil)
}
@IBOutlet var image: UIImageView!=nil
@IBAction func submit(_ sender: Any) {
if name.text != "" && email.text != ""
{
let entityDescription = NSEntityDescription.entity(forEntityName: "Table", in: context)
let item = Item(entity: entityDescription!, insertInto: context)
item.name = name.text
item.email = email.text
item.image = image.image!.pngData()! as NSData
do {
try context.save()
print("saved this moc")
} catch {
return
}
let UserDetailsVc = self.storyboard?.instantiateViewController(withIdentifier: "ViewController") as! ViewController
self.navigationController?.pushViewController(UserDetailsVc, animated: true)
}
else
{
print("mail check")
let alertController1 = UIAlertController (title: "Fill Email id", message: "Enter valid email", preferredStyle: UIAlertController.Style.alert)
alertController1.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
present(alertController1, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
if item != nil {
name.text = item?.name
email.text = item?.email
image.image = UIImage(data: (item?.image)! as Data)
}
}
此控制器用于获取所有内容
class ViewController: UIViewController ,UITableViewDataSource,UITableViewDelegate,NSFetchedResultsControllerDelegate{
var userarray: [Table] = []
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return userarray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell", for: indexPath) as! TableViewCell
let name = userarray[indexPath.row]
cell.username.text = name.name
cell.showImage?.image = UIImage(data: (name.image)!)
return cell
}
@IBOutlet var table: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
fetchData()
}
override func viewWillAppear(_ animated: Bool) {
fetchData()
}
func fetchData(){
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
do {
userarray = try context.fetch(Table.fetchRequest())
print(userarray,"user")
}catch{
print("error")
}
}
}