无法通过当前模态转换将图像传递给另一个 UIViewController

Question

我试图将图像传递到目标 UIView 的另一个 imageView，它连接到源 UIView，超过当前模态转场。

我试图通过 segue 传递数据，并通过 Outlet 在源 UIView 中设置图像（即 NSData - 核心数据），但我在控制台中收到错误 image description -

"fatal error: unexpectedly found nil while unwrapping an Optional value"

  //Code of destination UIView
   import UIKit
   import CoreData
   class ReviewViewController: UIViewController {

   @IBOutlet var backgroundImageView:UIImageView!
   var subject:Semester!       

    override func viewDidLoad() {
    super.viewDidLoad()
    backgroundImageView?.image = UIImage(data: subject.image!)
    let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark)
    let blurEffectView = UIVisualEffectView(effect: blurEffect)
    blurEffectView.frame = view.bounds
    backgroundImageView.addSubview(blurEffectView)

   // Code of Source UIView
  import UIKit
  import CoreData

  class SubjectDetailViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
  @IBOutlet var facultyImageView:UIImageView!
  var subject:Semester!

  override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "destinationidentifier"
    {
            let destinationController = segue.destinationViewController as! ReviewViewController
            destinationController.backgroundImageView?.image = self.facultyImageView.image
     }
}

Answer 1

您做错了，因为您直接在 outlet 内设置图像，而没有使用 var 或属性传递值。

1) 先声明变量

var backgroundImage : UIImage!

2) 在 push

时设置该变量内的值

destinationController.backgroundImage = self.facultyImageView.image

Answer 2

您的问题是 backgroundImageView 对象为零，因为 destinationController 当前不在 window 层次结构中。

所以像这样改变你的prepareForSegue

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "destinationidentifier"
    {
        let destinationController = segue.destinationViewController as! ReviewViewController
        destinationController.image = self.facultyImageView.image
    }
}

现在在 ReviewViewController 中创建一个图像对象，如下所示，并在 viewDidLoad

中添加一行

var image: UIImage!

override func viewDidLoad() {
    super.viewDidLoad()
    self.backgroundImageView?.image = self.image
}

希望对您有所帮助

Answer 3

像这样修改您的代码，尝试使用 UIImage 而不是 ImageView 发送图像，

//Code of destination UIView
import UIKit
import CoreData
class ReviewViewController: UIViewController {

@IBOutlet var backgroundImageView:UIImageView!
var backgroundImage : UIImage!
var subject:Semester!       

override func viewDidLoad() {
super.viewDidLoad()
//backgroundImageView?.image = UIImage(data: subject.image!)
backgroundImageView?.image = self. backgroundImage
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
backgroundImageView.addSubview(blurEffectView)

// Code of Source UIView
import UIKit
import CoreData

class SubjectDetailViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
@IBOutlet var facultyImageView:UIImageView!
var subject:Semester!

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)        {
if segue.identifier == "destinationidentifier"
{
        let destinationController = segue.destinationViewController as! ReviewViewController
        destinationController.backgroundImage = self.facultyImageView.image
 }
}

希望对您有所帮助。

无法通过当前模态转换将图像传递给另一个 UIViewController

Unable to pass image to another UIViewController over present modally segue

macos

xcode

ios

xcode7