以编程方式设置UIButton的目标/操作？

Question

在我的应用程序中，我有一个流程如下：用户按下一个更改UIBarButtonItems的按钮，当用户点击其中一个时，其更改为其他内容。 但是，当我点击其中一个时，我得到以下异常。

  *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[App.MapViewController revealLeftView]: unrecognized selector sent to instance 0x7fbc90c404c0'

首先，故事板中添加的按钮的动作设置如下：

menuButton.action = #selector(PBRevealViewController.revealLeftView)
toolboxMenuButton.action = #selector(PBRevealViewController.revealRightView)

当用户点击屏幕上其他位置的按钮时，我会像这样更改UIBarButtons：

let leftButton: UIButton = UIButton(type: UIButtonType.custom)
//set image for button
leftButton.setImage(UIImage(named: "close"), for: UIControlState.normal)
//add function for button
leftButton.addTarget(self, action: #selector(MapViewController.cancelAddFields), for: UIControlEvents.touchUpInside)
//set frame
leftButton.frame = CGRect(x: 0, y: 0, width: 20, height: 20)
let leftBarButton = UIBarButtonItem(customView: leftButton)

let rightButton: UIButton = UIButton(type: UIButtonType.custom)
//set image for button
rightButton.setImage(UIImage(named: "add"), for: UIControlState.normal)
//add function for button
rightButton.addTarget(self, action: #selector(MapViewController.confirmCreateFields(sender:)), for: UIControlEvents.touchUpInside)
//set frame
rightButton.frame = CGRect(x: 0, y: 0, width: 24, height: 20)
let rightBarButton = UIBarButtonItem(customView: rightButton)

//assign button to navigationbar
self.navigationItem.rightBarButtonItem = rightBarButton
self.navigationItem.leftBarButtonItem = leftBarButton

这可以正常工作，当用户单击关闭按钮时，我更改了UIBarButtonItems，如下所示：

let leftButton: UIButton = UIButton(type: UIButtonType.custom)
        //set image for button
        leftButton.setImage(UIImage(named: "MenuIcon_1"), for: UIControlState.normal)
        //add function for button
        //leftButton.addTarget(self, action: #selector(MapViewController.cancelAddFields), for: UIControlEvents.touchUpInside)
        //set frame
        leftButton.frame = CGRect(x: 0, y: 0, width: 24, height: 24)

        let rightButton: UIButton = UIButton(type: UIButtonType.custom)
        //set image for button
        rightButton.setImage(UIImage(named: "ToolsIcon_1"), for: UIControlState.normal)
        //add function for button
        //rightButton.addTarget(self, action: #selector(MapViewController.cancelAddFields), for: UIControlEvents.touchUpInside)
        //set frame
        rightButton.frame = CGRect(x: 0, y: 0, width: 24, height: 24)

        leftButton.addTarget(self, action: #selector(PBRevealViewController.revealLeftView), for: UIControlEvents.touchUpInside)
        rightButton.addTarget(self, action: #selector(PBRevealViewController.revealRightView), for: UIControlEvents.touchUpInside)

        let leftBarButton = UIBarButtonItem(customView: leftButton)
        let rightBarButton = UIBarButtonItem(customView: rightButton)
        //assign button to navigationbar
        self.navigationItem.rightBarButtonItem = rightBarButton
        self.navigationItem.leftBarButtonItem = leftBarButton

它显示一切都很好，但是当我点击其中一个时，它会抛出上面提到的异常。 我究竟做错了什么？ 我已经尝试过UIBarButtonItem本身的.action，似乎也没有用。

Answer 1

似乎在：

leftButton.addTarget(self, action: #selector(PBRevealViewController.revealLeftView), for: UIControlEvents.touchUpInside)

self （目标）实际上不是PBRevealViewController的实例，而是MapViewController 。 这意味着你告诉按钮在MapViewController上调用方法revealLeftView 。

确保使用正确的target 。