如果选择器是有条件的，则可以更改它。 请看下面的例子

您可以先删除所有目标，然后选择选择器并添加它。

rateButton。removeTarget(nil，动作:nil, for: .allEvents)

    let action = interview.isRated ? #selector(viewTapped(_:)) : #selector(rateTapped(_:))
            
    rateButton.addTarget(self, action: action, for: .touchUpInside)

斯威夫特2:

actionButton.removeTarget(nil, action: nil, forControlEvents: .AllEvents)

Swift 3和4:

actionButton.removeTarget(nil, action: nil, for: .allEvents)

objective - c:

[actionButton removeTarget: nil action: NULL forControlEvents: UIControlEventAllEvents];

调用removeTarget:action:forControlEvents:，为目标传递nil，为动作传递NULL，并使用一个设置所有位的控制掩码(UIControlEventAllEvents)。

objective - c

[someControl removeTarget:nil 
                   action:NULL 
         forControlEvents:UIControlEventAllEvents];

斯威夫特2

button.removeTarget(nil, action: nil, forControlEvents: .AllEvents)

Swift 3或更高

button.removeTarget(nil, action: nil, for: .allEvents)

如果选择器是有条件的，则可以更改它。 请看下面的例子

您可以先删除所有目标，然后选择选择器并添加它。

rateButton。removeTarget(nil，动作:nil, for: .allEvents)

    let action = interview.isRated ? #selector(viewTapped(_:)) : #selector(rateTapped(_:))
            
    rateButton.addTarget(self, action: action, for: .touchUpInside)

@ program在Swift 2中的回答:

button.removeTarget(nil, action: nil, forControlEvents: .AllEvents)

Swift 3:

button.removeTarget(nil, action: nil, for: .allEvents)

注意:Swift没有NULL，所以我测试用nil替换它，它似乎工作得很好。

- removeTarget:action:forControlEvents:

此方法停止将事件传递到指定的目标对象。

Specifying a valid object in the target parameter, this method stops the delivery of the specified events to all action methods associated with that object. Specifying nil for the target parameter, this method prevents the delivery of those events to all action methods of all target objects objective-c: [_myButton removeTarget: //any validObject (or) nil action:nil forControlEvents:UIControlEventAllEvents]; swift: myButton.removeTarget(*validObject or nil*, action:nil, forControlEvents:UIControlEvents.AllEvents)

详情https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIControl_Class/index.html#//apple_ref/occ/instm/UIControl/removeTarget:action:forControlEvents: