更改 Swift 3 中 UIBarButtonItem（图像）的大小

我正在尝试更改导航栏中某些图标的大小，但我对如何执行此操作有点困惑？到目前为止我的代码是：

func setUpNavBarButtons() {
    let moreButton = UIBarButtonItem (image: UIImage(named:"ic_more_vert_3")?.withRenderingMode(.alwaysOriginal), style: .plain, target: self, action: #selector(handleMore))
    navigationItem.rightBarButtonItems = [moreButton]
    let refreshButton = UIBarButtonItem (image: UIImage(named:"ic_refresh")?.withRenderingMode(.alwaysOriginal), style: .plain, target: self, action: #selector(refreshDataButton))
    navigationItem.leftBarButtonItems = [refreshButton]
}

有什么帮助吗？

我就是这样做的

iOS 10 及以下版本

func setUpMenuButton(){
    let menuBtn = UIButton(type: .custom)
    menuBtn.frame = CGRect(x: 0.0, y: 0.0, width: 20, height: 20)
    menuBtn.setImage(UIImage(named:"menuIcon"), for: .normal)
    menuBtn.addTarget(self, action: #selector(vc.onMenuButtonPressed(_:)), for: UIControlEvents.touchUpInside)

    let menuBarItem = UIBarButtonItem(customView: menuBtn)
    self.navigationItem.leftBarButtonItem = menuBarItem
}

iOS 11 - 导航栏带有自动布局，因此框架设置可能不起作用

func setUpMenuButton(){
    let menuBtn = UIButton(type: .custom)
    menuBtn.frame = CGRect(x: 0.0, y: 0.0, width: 20, height: 20)
    menuBtn.setImage(UIImage(named:"menuIcon"), for: .normal)
    menuBtn.addTarget(self, action: #selector(vc.onMenuButtonPressed(_:)), for: UIControlEvents.touchUpInside)

    let menuBarItem = UIBarButtonItem(customView: menuBtn)
    let currWidth = menuBarItem.customView?.widthAnchor.constraint(equalToConstant: 24)
    currWidth?.isActive = true
    let currHeight = menuBarItem.customView?.heightAnchor.constraint(equalToConstant: 24)
    currHeight?.isActive = true
    self.navigationItem.leftBarButtonItem = menuBarItem
}