Ios 调整UIBarButtonItems的大小

如何调整UIBarButtonims的大小？下面是我如何为webview设置导航栏按钮项

        navForwardButton = UIBarButtonItem.init(image: navRightImage, style: UIBarButtonItem.Style.plain, target: self, action: #selector(navigateForwardButtonClicked))
        navBackwardButton = UIBarButtonItem.init(image: navLeftImage, style: UIBarButtonItem.Style.plain, target: self, action: #selector(navigateBackwardButtonClicked))
        cancelButton = UIBarButtonItem.init(title: "Cancel", style: UIBarButtonItem.Style.plain, target: self, action: #selector(cancelButtonClicked))

看起来像

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如何使这些按钮项变小

您也可以这样添加

    func addRightButton(){

    let viewFN = UIView(frame: CGRectMake(0, 0, 180,40))
        viewFN.backgroundColor = UIColor.yellowColor()
    let button1 = UIButton(frame: CGRectMake(0,8, 40, 20))
    button1.setImage(UIImage(named: "notification"), forState: UIControlState.Normal)
    button1.setTitle("one", forState: .Normal)

    button1.addTarget(self, action: #selector(self.didTapOnRightButton), forControlEvents: UIControlEvents.TouchUpInside)

    let button2 = UIButton(frame: CGRectMake(40, 8, 60, 20))
    button2.setImage(UIImage(named: "notification"), forState: UIControlState.Normal)
    button2.setTitle("tow", forState: .Normal)
    let button3 = UIButton(frame: CGRectMake(80, 8, 60, 20))
     button3.setImage(UIImage(named: "notification"), forState: UIControlState.Normal)
    button3.setTitle("three", forState: .Normal)

    button3.addTarget(self, action: #selector(self.didTapOnRightButton), forControlEvents: UIControlEvents.TouchUpInside)

    viewFN.addSubview(button1)
    viewFN.addSubview(button2)
    viewFN.addSubview(button3)


    let rightBarButton = UIBarButtonItem(customView: viewFN)
    self.navigationItem.rightBarButtonItem = rightBarButton

 }

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嘿，这很有效，非常感谢。但这似乎是一个需要大量工作的东西，应该是自动的