我如何快速用自定義視圖以編程方式替換 IBOutlet uiview

Question

它在故事板中有一個replacementView UIView作為UIView

@IBOutlet var replacementView: UIView!

連接。

我想用替換replacementView

replacementView = SecondViewController().view

但它不起作用。 有什么問題？

Answer 1

replacementView只是參考。 您必須更改視圖堆棧中的對象。

您應該保留對replacementView的父級的引用。 接下來從parentView 中刪除replacementView並將SecondViewController().view添加到parentView。

我建議您嘗試將您的SecondViewController().view添加為replacementView並添加填充約束。

您還應該記住保留 SecondViewController，否則它可能會在出現之前被解除分配。 閱讀addChildViewController(childController: UIViewController) UIViewController 方法。

Answer 2

本質上，您需要向要添加的視圖添加約束，然后刪除舊視圖。 假設項目在您的父視圖中按順序排列，這里有一些代碼可以為您執行此操作。

func replaceView(oldView:UIView, newView: UIView, spacingBetweenViews: CGFloat) {
    //loop through, find the view, and add a constraint between the next and previous items.
    let parentView = oldView.superview ?? UIView()
    for (index, subview) in parentView.subviews.enumerated() {
        let PREVIOUS_VIEW = index - 1
        let NEXT_VIEW = index + 1
        if subview == oldView {
            if index == 0 {
                //if the first view
                let constraints = [
                    parentView.topAnchor.constraint(
                        equalTo: newView.topAnchor,
                        constant: spacingBetweenViews),
                    newView.bottomAnchor.constraint(
                        equalTo: parentView.subviews[NEXT_VIEW].topAnchor,
                        constant: spacingBetweenViews)
                ]
                NSLayoutConstraint.activate(constraints)
            } else if index == parentView.subviews.count - 1 {
                // if the last view
                let constraints = [
                    parentView.subviews[PREVIOUS_VIEW].bottomAnchor.constraint(
                        equalTo: newView.topAnchor,
                        constant: spacingBetweenViews),
                    newView.bottomAnchor.constraint(
                        equalTo: parentView.bottomAnchor,
                        constant: spacingBetweenViews)
                ]
                NSLayoutConstraint.activate(constraints)
            } else {
                let constraints = [
                    parentView.subviews[PREVIOUS_VIEW].bottomAnchor.constraint(
                        equalTo: newView.topAnchor,
                        constant: spacingBetweenViews),
                    newView.bottomAnchor.constraint(
                        equalTo: parentView.subviews[NEXT_VIEW].topAnchor,
                        constant: spacingBetweenViews)
                ]
                NSLayoutConstraint.activate(constraints)
            }
            parentView.subviews[index].removeFromSuperview()
        }
    }
}