以 Xib 作为根视图的自定义视图

【问题标题】：Custom View with Xib as root View以 Xib 作为根视图的自定义视图
【发布时间】：2019-09-04 18:25:33
【问题描述】：

创建自定义视图时，是否可以将根视图设置为xib？

目前，如果我创建自定义视图，我需要将笔尖添加为子视图。

如果我想更改背景颜色，我将无法再使用 UIView API。

customView.backgroundColor = UIColor.red // Won't work because nib view is covering the "root" view.

那么，有没有可能做到这一点..

class CustomView: UIView {

    func commonInit() {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: getInheritedClassName(object: type(of: self)), bundle: bundle)
        let view = nib.instantiate(withOwner: self, options: nil).first as! UIView
        // Currently doing this..
        addSubview(view)
        // Can we do this somehow?
        self = view // Set self as the xib view
    }
}

【问题讨论】：

标签： ios swift xib nib

【解决方案1】：

使用 awakeAfter：

open override func awakeAfter(using _: NSCoder) -> Any? {
    // set the tag in the view's XIB, so we don't create an infinite loop
    guard tag != 999 else {
        return self
    }

    let view = type(of: self).instantiate() // Convenience method that chooses nib based on class name
    view.frame = frame
    view.autoresizingMask = autoresizingMask
    view.translatesAutoresizingMaskIntoConstraints = translatesAutoresizingMaskIntoConstraints
    view.tag = tag
    for constraint in constraints {
        let firstItem = constraint.firstItem as? UIView == self ? view : constraint.firstItem
        let secondItem = constraint.secondItem as? UIView == self ? view : constraint.secondItem
        let constraintToAdd = NSLayoutConstraint(item: firstItem as Any, attribute: constraint.firstAttribute, relatedBy: constraint.relation, toItem: secondItem, attribute: constraint.secondAttribute, multiplier: constraint.multiplier, constant: constraint.constant)
        constraintToAdd.priority = constraint.priority
        view.addConstraint(constraintToAdd)
    }

    return view
}

【讨论】：