2

在这种特殊情况下，我实际上很困惑。我对 UINavigationBar 进行了子类化，注意到 Apple 过时的示例代码，意识到 sizeToFit 永远不会被调用和覆盖intrinsicContentSize并layoutSubviews计算必要的高度。在根据我提供的自定义视图计算高度时，一切都很好（我systemLayoutSizeFittingSize用于根据自定义内容视图/标题视图动态计算高度）。

奇怪的是，当我尝试为任何更改设置动画时，我可以为 custom 中的更改设置动画titleView，但是当通过 重新加载intrinsicContentSize 时invalidateIntrinsicContentSize()，视图框架更改不会设置动画。它啪啪啪。

示例代码：

let delta = destinationTextFieldContainerView.frame.minX - originTextFieldContainerView.frame.minX + originTextFieldContainerView.frame.height
textContainersSeparatorConstraint.constant = -delta
UIView.animateWithDuration(2, delay: 2, options: UIViewAnimationOptions.CurveEaseIn, animations: {
    self.customContainerNavigationBar.invalidateIntrinsicContentSize()
    self.customContainerNavigationBar.layoutIfNeeded()

    }) { (_) in
        self.customContainerNavigationBar.invalidateIntrinsicContentSize()
}

一个约束值更改将动画化，但不幸的是（因为 navBars 不依赖自动布局）似乎更新框架存在问题。我尝试在使固有大小无效之前直接更新框架，但没有成功。我还尝试了高度约束，将其列在具有不同时间偏移的关键帧动画中，在不同的时间点使布局无效，但都没有成功。任何帮助将不胜感激。

可以在这里找到调整大小的代码：

override func intrinsicContentSize() -> CGSize {
    var navigationBarSize = super.intrinsicContentSize()
    navigationBarSize.width = superview?.frame.width ?? 0

    guard let  titleView = navigationItem?.titleView else {
        return navigationBarSize
    }
    let fittingSize = CGSize(width: navigationBarSize.width, height: UILayoutFittingCompressedSize.height)
    let titleViewSize = titleView.systemLayoutSizeFittingSize(fittingSize)

    navigationBarSize.height = max(titleViewSize.height, 44)

    navigationBarSize.width = UIViewNoIntrinsicMetric
    return navigationBarSize
}


override func layoutSubviews() {

    super.layoutSubviews()

    guard let navigationItem = navigationItem, titleView = navigationItem.titleView else {
        return
    }
    var navigationBarSize = bounds.size
    navigationBarSize.width = superview?.frame.width ?? 0

    var fittingSize = CGSize(width: navigationBarSize.width, height: UILayoutFittingCompressedSize.height)

    if let leftBarButtonItem = navigationItem.leftBarButtonItem, leftButtonCustomView = leftBarButtonItem.customView {
        fittingSize.width -= leftButtonCustomView.frame.width + leftButtonCustomView.frame.origin.x + 22
    }

    let titleViewSize = titleView.systemLayoutSizeFittingSize(fittingSize, withHorizontalFittingPriority: UILayoutPriorityRequired, verticalFittingPriority: UILayoutPriorityDefaultLow)

    titleView.frame = CGRect(origin: CGPoint(x: titleView.frame.origin.x, y: 0), size: titleViewSize)
    titleView.setNeedsLayout()
    titleView.layoutIfNeeded()

    if let leftBarButtonItem = navigationItem.leftBarButtonItem, leftButtonCustomView = leftBarButtonItem.customView {
        var customViewFrame = CGRect(origin: CGPoint.zero, size: navigationBarSize)

        let customViewSize = leftButtonCustomView.systemLayoutSizeFittingSize(customViewFrame.size, withHorizontalFittingPriority: UILayoutPriorityDefaultLow, verticalFittingPriority: UILayoutPriorityDefaultLow)
        customViewFrame.size = customViewSize
        leftButtonCustomView.frame = customViewFrame
        leftButtonCustomView.setNeedsLayout()
        leftButtonCustomView.layoutIfNeeded()
    }

    invalidateIntrinsicContentSize()

}
4

0 回答 0