有没有办法从 UIControl 中删除所有 UIAction？

Question

或者有没有办法检查 UIControl 是否有任何 UIActions？

有时我想改变 UIControl 的行为。当使用目标动作时，我可以这样做

button.removeTarget(nil, action: nil), for: .touchUpInside)
button.addTarget(self, action: #selector(didTouchUpInside()), for: .for: .touchUpInside)

Answer 1

您可以使用以下方法执行此操作enumerateEventHandlers：

button.enumerateEventHandlers { action, targetAction, event, stop in
    if let action = action {
        // This is a UIAction
        button.removeAction(action, for: event)
    }
    if let (target, selector) = targetAction {
        // This is target / action
        button.removeTarget(target, action: selector, for: event)
    }
    stop = true // Ends iterating early if you are done
}