Swift 2.3 中给 UIBarButtonItem 添加点击事件:
let btn = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.add, target: self, action: #selector(action))
self.navigationItem.rightBarButtonItem = btn
在 Swift 4.0 中会报错:Argument of '#selector' refers to instance method 'action' that is not exposed to Objective-C。解决办法有两种:
1、在该类前加上:
@objcMembers
class ViewController: UIViewController {
}
2、在方法名前加上:
@objc func action() {
print("add")
}