UIBarButtonItem遇到的坑

        letcancleBtn =UIButton()

//iOS9.0必须要给button设置frame，但是iOS12上面，customView会自动布局

        cancleBtn.frame=CGRect(x:0, y:0, width:60, height:40)

        cancleBtn.setTitle("取消", for: .normal)

        cancleBtn.titleEdgeInsets=UIEdgeInsetsMake(0,0,0,-40)

        cancleBtn.titleLabel?.font=UIFont.systemFont(ofSize:14)

        cancleBtn.setTitleColor(UIColor(hex:"999999"), for: .normal)

        cancleBtn.addTarget(self.navigationController, action:#selector(HBImagePickerViewController.goBack) , for:.touchUpInside)

        self.navigationItem.rightBarButtonItem = UIBarButtonItem.init(customView: cancleBtn)