为什么按钮只在第二次尝试时出现？

Question

我正在尝试添加一个功能，该功能将在我的自定义警报视图中显示关闭按钮。当我第一次调用它时，只出现一个不包含按钮的空白区域（没有颜色，没有文本，也没有按下）。当您再次调用时 - 一切正常。

它不依赖于参数animated，在这两种情况下它的工作原理相同。

我的 dialogView 是我的习惯 UIView。我不使用 UIAlertController

可能是什么问题？

initial view after the first attempt second attempt
GIF call func by click

func showCloseButton(text: String, animated: Bool){
        let dialogViewHeight = self.dialogView.frame.height + 50 + 1

        let button = UIButton(type: .roundedRect)
        button.backgroundColor = .red
        button.frame.origin = CGPoint(x: 0, y: dialogViewHeight)
        button.frame.size = CGSize(width: self.dialogView.frame.width, height: 50)
        button.setTitle(text, for: .normal)
        button.addTarget(self, action: #selector(closeTapped), for: .touchUpInside)

        let separatorLineView = UIView()
        separatorLineView.frame.origin = CGPoint(x: 0, y: self.dialogView.frame.height)
        separatorLineView.frame.size = CGSize(width: dialogView.frame.width, height: 1)
        separatorLineView.backgroundColor = UIColor.groupTableViewBackground
        dialogView.addSubview(separatorLineView)

        if animated {
            animateAdjustDialogView(height: dialogViewHeight){
                Logger.Log("completion did")
                self.dialogView.addSubview(button)
            }
        } else {

            Logger.Log("button.frame.origin = \(button.frame.origin)")
            Logger.Log("button.frame.size = \(button.frame.size)")
            Logger.Log("button.title = \(button.titleLabel)")

            self.dialogView.frame.size = CGSize(width: self.dialogView.frame.width, height: dialogViewHeight)
            self.dialogView.addSubview(button)
        }
    }

private func animateAdjustDialogView(height: CGFloat, completion: (()->Void)?){
        UIView.animate(withDuration: 1.0, animations: {
            self.dialogView.frame.size = CGSize(width: self.dialogView.frame.width, height: height)
            self.layoutIfNeeded()
        }) { (finished) in
            Logger.Log("finished = \(finished)")
            if finished {
                Logger.Log("completion run")
                completion?()
            }
        }
    }

Answer 1

按钮框架导致了问题 -

button.frame.origin = CGPoint(x: 0, y: dialogViewHeight)

哪里

let dialogViewHeight = self.dialogView.frame.height + 50 + 1

也就是说，button超越了dialogViewframe。

所以替换

button.frame.origin = CGPoint(x: 0, y: dialogViewHeight)

与

button.frame.origin = CGPoint(x: 0, y: dialogViewHeight - 50) // Height of the Button.

如果您还有任何问题，请告诉我。

为什么按钮只在第二次尝试时出现？

Why button appears only on the second attempt?

ios

swift

uiview

uibutton

addsubview