解决[UITapGestureRecognizer tag]: unrecognized selector sent to instance
//这样写就会崩溃addGestureRecognizer(UITapGestureRecognizer(target:self,action:#selector(cancel)))@objcprivatefunccancel(){}//这样写就不会崩溃addGestureRecognizer(UITapGestureRecognizer(target:self,action:#selector(