Question

我尝试使用UIimageview调用的类中的方法更新viewDidLoad()图像。我试图改变图像：

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

但它给我的错误是：

Instance member cannot be used on type "view controller"

我哪里错了？

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

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 2

以下是更正后的代码的摘录，但行中出现相同的错误：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 3

以下是有效的解决方案：

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())
}

}

）

Swift 3：实例成员不能用于“视图控制器”类型

3 个答案: