Question

在这里，我以编程方式使用了活动指示器并以编程方式给出了约束，但在NSLayoutConstraint崩溃时返回错误，任何人都可以帮我解决这个问题吗？

这是我在控制台中的错误

2017-11-04 16：46：41.657电子商务[2744：71044] ***终止应用程序到期未被捕获的异常＆＃39; NSGenericException＆＃39;，原因：＆＃39;无法用锚点激活约束因为他们没有共同的祖先。约束或其约束锚点引用不同视图层次结构中的项目？那＆＃39; S 。非法＆＃39;

func showActivityIndicator(uiView: UIView) {
    container.frame = uiView.frame
    container.center = uiView.center
    container.backgroundColor = UIColorFromHex(rgbValue: 0xffffff, alpha: 0.3)

    loadingView.frame = CGRect(x: 0, y: 0, width: 80, height: 80)
    loadingView.center = uiView.center
    loadingView.backgroundColor = UIColorFromHex(rgbValue: 0x444444, alpha: 0.7)
    loadingView.clipsToBounds = true
    loadingView.layer.cornerRadius = 10

    customActivityIndicator.frame = CGRect(x: 0, y: 0, width: 40, height: 40)
    customActivityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.whiteLarge
    customActivityIndicator.center = CGPoint(x: loadingView.frame.size.width / 2, y: loadingView.frame.size.height / 2)

    loadingView.addSubview(customActivityIndicator)
    view.isUserInteractionEnabled = false
    container.addSubview(loadingView)
    container.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint(
        item: container,
        attribute: .centerX,
        relatedBy: .equal,
        toItem: view,
        attribute: .centerX,
        multiplier: 1.0,
        constant: 0.0
        ).isActive = true

    NSLayoutConstraint(
        item: container,
        attribute: .centerY,
        relatedBy: .equal,
        toItem: view,
        attribute: .centerY,
        multiplier: 1.0, 
        constant: 0.0
        ).isActive = true
    NSLayoutConstraint(item: container, attribute: .width, relatedBy: .equal, toItem: contentView, attribute: .width, multiplier: 1, constant: view.frame.size.width / 2).isActive = true
    NSLayoutConstraint(item: container, attribute: .height, relatedBy: .equal, toItem: contentView, attribute: .height, multiplier: 1, constant: view.frame.size.height / 2).isActive = true
    contentView.addSubview(container)
    customActivityIndicator.startAnimating()
}

Answer 1

在创建约束之前添加子视图。

移动此行：

contentView.addSubview(container)

在创建/激活约束之前。

如何解决Swift 3中的Autolayout问题？

1 个答案: