Swift 3:实例成员不能用于类型“视图控制器”

Question

我正在尝试使用具有viewDidLoad()调用的类内的方法更新UIimageview图像。我正在尝试通过以下方式更改图像：

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

但它给了我以下错误：

Instance member cannot be used on type "view controller"

我哪里出错了？

我的代码：

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

这是更正的代码的摘录，但行中具有相同的错误： let _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
    }
}

Answer 2

我认为

您的问题是结构无法使用ViewController类中的变量，因此我将其更改为执行相同操作的函数：

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

这是有效的解决方案：

导入 UIKit
类视图控制器： 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())
}
 

}

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