Question

我想创建一个UnsafeMutablePointer对象来指向/表示一个现有的UIColor对象。提供的初始化程序不提供此选项AFAIK。我能做什么？我想做这样的事情：

var myColor = UIColor.white
var pointer = UnsafeMutablePointer<UIColor>.init(from: myColor)
let color = pointer.pointee
// color == UIColor.white
pointer.pointee = UIColor.orange
// now myColor == UIColor.orange

我正在使用Swift 4.2

编辑：应评论者的要求，我正在发布真实代码：

let variableForColor : (_ key: String, _ color: UnsafeMutablePointer<UIColor>) -> StorableVariable.ValueForUIColor = { key, color in
    return StorableVariable.ValueForUIColor.from(color: color.pointee, listener: { [weak self] v in
        color.pointee = v.toUIColor()
        self?.editor?.restyle()
    })
}
...
let v = variableForColor("/button/circle/normal/fill/color", &editor!.styleOrangeButtonCircleNormalFillColor) // styleOrangeButtonCircleNormalFillColor is UIColor var in editor

编辑：以下是尝试使用inout和Float的解决方案，但编译器不允许这样做：

let variableForFloatIO : (_ key: String, _ float:inout Float) -> StorableVariable.ValueForFloat = { key, float in
    return StorableVariable.ValueForFloat.init(value: float, default: float, min: 0, max: 1, step: 0.01, listener: { [weak self] v in
        float = v // Error: Escaping closures can only capture inout parameters explicitly by value
        self?.editor?.restyle()
    })
}

Swift：将UnsafeMutablePointer初始化为现有的UIColor对象

0 个答案: