Swift4给按钮添加点击事件

开发调优
1 
// 监听按钮点击事件  
btn.addTarget(self, action: #selector(MainViewController.composeBtnClick), for: UIControlEvents.touchUpInside)  

@objc private func composeBtnClick(btn: UIButton) {  
	myLog(btn)  
}

@objc 使方法支持动态派发，不加可能会报这样的错

‘#selector’ does not refer to an ‘@objc’ method,No method declared with Objective-C selector 'compos