错误:“无法分配给'Bool'类型的不可变表达式"? [英] Error: "Cannot assign to immutable expression of type 'Bool'"?

问题描述

我该如何解决?我是新编码员.谢谢

How do I fix this? I'm a new coder. Thank you

我收到以下错误:

无法分配给'布尔'类型的不可变表达式"

"Cannot assign to immutable expression of type 'Bool'"

当我尝试将"isSelected"设置为false和true

When I try to set the "isSelected" to false and true

@IBAction func onFilter(_ sender: Any) {

    if ((sender as AnyObject).isSelected == true) {

        hideSecondaryMenu()
        (sender as AnyObject).isSelected = false

    } else {

        showSecondaryMenu()
        (sender as AnyObject).isSelected = true

    }
}

推荐答案

出现此错误是因为将发件人转换为AnyObject时会得到immutable类型的对象，因此无法更新其属性，最佳选择解决您的问题的方法是将发件人声明从Any更改为实际的UIControl意味着如果它是按钮，则将UIButton.

You are getting this error because when you are converting sender to AnyObject you are getting immutable type object so you cannot update its properties, The best option to solved your problem is to change your sender declaration from Any to actual UIControl means if it is button then UIButton.

@IBAction func onFilter(_ sender: UIButton) {
    hideSecondaryMenu()
    sender.isSelected = !sender.isSelected
}

如果您仍要使用Any，则将发件人转换为它所属的实际UIControl.

If you want to still use Any then convert sender to actual UIControl that it is belong to.

@IBAction func onFilter(_ sender: Any) {
    if sender is UIButton {
         let btn = sender as! UIButton
         hideSecondaryMenu()
         btn.isSelected = !btn.isSelected
    }
}    

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