Swift:将 subview 添加到另一个 subview

Question

我正在努力向 View 添加 subview 。进度变量在其 View Controller 的 viewDidLoad() 中设置。 progressView frame size 设置正确，只是添加了好像出错的subview。知道缺少什么吗？

class ProgressBar: UIView {
    var progressView = UIView()
    var progress: CGFloat? {
        didSet {
            setProgressBar(progress: progress!)
        }
    }

    func setProgressBar(progress: CGFloat) {
        self.layer.masksToBounds = true
        let progressViewWidth: CGFloat = self.frame.width * progress
        progressView.backgroundColor = .red
        progressView.frame = CGRect(origin: frame.origin,
                                    size: CGSize(width: progressViewWidth, height: frame.height))
        self.addSubview(progressView)
    }
}

Answer 1

progressView.frame = CGRect(origin: frame.origin, size: CGSize(width: progressViewWidth, height: frame.height))

应该这样替换

progressView.frame = CGRect(origin: CGPoint.zero, size: CGSize(width: progressViewWidth, height: frame.height))

progressView的位置与progressBar的有关