Swift 3：實例成員不能在類型「視圖控制器」上使用

Question

我試圖使用調用viewDidLoad()調用的類中的方法更新UIimageview圖像。我試圖改變由圖像：

MyIMage.image = UIImage(named: "image2") 

但它給我的錯誤：

Instance member cannot be used on type "view controller" 

我要去哪裏錯了？

我的代碼：

import UIKit 

class ViewController: UIViewController { 

    @IBOutlet var MyImage: UIImageView! 

    var MyStruct = ChangeImage() 

    struct ChangeImage { 

     private var _isChanged: Bool = false 

     mutating func Set_Change(val: Bool) { 

      if (val) { 
       MyImage.image = UIImage(named: "image2") 
       self._isChanged = true 
      } else { 
       MyImage.image = UIImage(named: "image1") 
       self.isChanged = false 
      } 
     } 

     func isChanged()-> Bool { 
      return self._isChanged 
     } 
    } 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     // Do any additional setup after loading the view, typically from a nib. 
     MyStruct.Set_Change(val: true) 
     print (MyStruct.isChanged()) 
    } 

} 

Answer 1

這裏有一個工作的解決方案：

 
import UIKit
 

class ViewController: UIViewController {
 

@IBOutlet var MyImage: UIImageView! // Insert Outlet Image : "MyImage" 

// Structure ChangeImage 
struct ChangeImage { 
    private var _isChanged: Bool = false 
    private var _myImage: UIImageView! // Private variable _myImage 

    init (ImgView: UIImageView) {  // Initiate ImgView called since func viewDidLoad() 
     self._myImage = ImgView   // Private variable _myImage = ImgView (variable MyImage in func viewDidLoad()) 
    } 

    mutating func Set_Change(val: Bool) { 

     if (val) { 
      _myImage.image = UIImage(named: "image2") 
      self._isChanged = true 
     } else { 
      _myImage.image = UIImage(named: "image1") 
      self._isChanged = false 
     } 
    } 

    func isChanged()-> Bool { 
     return self._isChanged 
    } 
} 

override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view, typically from a nib. 

    var MyStruct = ChangeImage(ImgView: MyImage) // Initiate Structure ChangeImage with variable MyImage. 
    MyStruct.Set_Change(val: true) 
    print (MyStruct.isChanged()) 
} 

}

;）

Answer 2

我覺得你的問題是結構不能從ViewController類中使用的變量，所以我把它改成，做同樣的事情的函數：

import UIKit 

class ViewController: UIViewController { 

    @IBOutlet var myImage: UIImageView! 

    func Set_Change(val: Bool) -> Bool { 

     if (val) { 
      myImage.image = UIImage(named: "image2") 
      return true 
     } else { 
      myImage.image = UIImage(named: "image1") 
      return false 
     } 
    } 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     // Do any additional setup after loading the view, typically from a nib. 
     let didChange = Set_Change(val: true) 
     print(didChange) 
    } 

} 

Answer 3

這裏是校正代碼的提取物，但與管線相同的錯誤：讓_myImage = MYIMAGE（）

class ViewController: UIViewController { 

@IBOutlet var MyImage: UIImageView! 

var MyStruct = ChangeImage() 

struct ChangeImage { 
    private var _isChanged: Bool = false 
    let _myImage = MyImage() // ----> Error : Instance member ‘MyImage’ cannot be used on type ‘ViewController’ 
    mutating func Set_Change(val: Bool) { 

     if (val) { 
      _myImage.image = UIImage(named: "image2") 
      self._isChanged = true 
     } else { 
      _myImage.image = UIImage(named: "image1") 
      self._isChanged = false 
     } 
    } 

    func isChanged()-> Bool { 
     return self._isChanged 
    } 
}