ios - 在 for 循环中将 subview 设置为 nil

Question

我正在尝试从其父 View 中删除 subview 和 View ，并将它们设置为零。我注意到 removeFromSuperview 方法没有将它们设置为 nil，这不是我想要的。我得到的错误是在 loadingViewSubviews[i] = nil 行。它说:不能通过下标赋值，loadingViewSubviews 是不可变的。我该如何克服这个问题？

这是我在 viewDidDisappear

中使用的代码

override func viewDidDisappear(animated: Bool) {
    super.viewDidDisappear(animated)
    var loadingViewSubviews = loadingView.subviews
    if loadingView != nil{
        for var i = 0; i < loadingViewSubviews.count; ++i{
            loadingViewSubviews[i].removeFromSuperview()
            loadingViewSubviews[i] = nil
        }
        loadingView.removeFromSuperview()
        loadingView = nil
    }
}

编辑:此代码创建 loadingView 及其 subview

var activityIndicator: UIActivityIndicatorView!
var activityLabel:UILabel!
var loadingView: UIView!




func processingIAP() {
        if loadingView == nil{
            activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.WhiteLarge)
            activityIndicator.hidesWhenStopped = true
            let labelRect = CGRectMake(activityIndicator.frame.width+6, 0, 200, activityIndicator.frame.height+12)
            activityLabel = UILabel(frame: labelRect)
            activityLabel.text = "Accessing store..."
            activityLabel.textColor = UIColor.whiteColor()
            activityLabel.adjustsFontSizeToFitWidth = true
            activityLabel.textAlignment = NSTextAlignment.Center
            let rect = CGRectMake(sceneView.frame.width/2.0-(activityIndicator.frame.width/2.0 + activityLabel.frame.width/2.0+12), sceneView.frame.height/2.0-(activityIndicator.frame.height/2.0), activityIndicator.frame.width + activityLabel.frame.width+24, activityIndicator.frame.height+12)
            loadingView = UIView(frame: rect)
            loadingView.backgroundColor = UIColor.blackColor()
            self.sceneView.addSubview(loadingView)
            loadingView.addSubview(activityIndicator)
            loadingView.addSubview(activityLabel)
            loadingView.layer.cornerRadius = 3
            loadingView.layer.borderWidth = 3
            loadingView.layer.borderColor = UIColor.whiteColor().CGColor
            activityIndicator.frame.origin = CGPointMake(6, (loadingView.frame.height-activityIndicator.frame.height)/2.0)
            activityIndicator.startAnimating()
        }else{
            activityLabel.text = "Accessing store..."
            activityIndicator.startAnimating()
            activityLabel.frame.origin.x += activityIndicator.frame.width
            activityLabel.frame.size.width -= activityIndicator.frame.width
        }

    }

Answer 1

如果您有对您的 subview 的引用，即使从父 View 中移除，它也不会自行销毁。

你可以这样做，但是在 objective-c 中:

while (self.subviews.count > 0) {
   id view = [self.subviews lastObject];
   [view removeFromSuperview];
   view = nil;
}