ios - 如何在 Swift 中用不同的 block 实现 objc_setAssociatedObject？

Question

正如标题所描述的那样。我终于找到了一个通用的解决方案，并展示给大家。并希望有人能有更好的解决方案。

Answer 1

只需按照以下步骤操作即可:

class BlockWrapper<T> {
    let block: T?
    init (_ b: T?) { self.block = b }
}

public typealias YourBlock = (param: [String:String]) -> Bool
public typealias YourBlock2 = () -> Bool

extension UIButton {
    @nonobjc static var iActionBlockKey = Int8(0);
    public var actionBlock: YourBlock? {
        set {
            objc_setAssociatedObject(self, &UIButton.iActionBlockKey, BlockWrapper<YourBlock>(newValue), .OBJC_ASSOCIATION_RETAIN)
        }
        get {
            let wrapper = objc_getAssociatedObject(self, &UIButton.iActionBlockKey) as? BlockWrapper<YourBlock>
            return wrapper?.block
        }
    }
    @nonobjc static var iActionBlockKey2 = Int8(0);
    public var actionBlock2: YourBlock2? {
        set {
            objc_setAssociatedObject(self, &UIButton.iActionBlockKey2, BlockWrapper<YourBlock2>(newValue), .OBJC_ASSOCIATION_RETAIN)
        }
        get {
            let wrapper = objc_getAssociatedObject(self, &UIButton.iActionBlockKey2) as? BlockWrapper<YourBlock2>
            return wrapper?.block
        }
    }
}