iOS 11 中的 UIBarButtonItem 间距问题

Question

我正在尝试调整 UIBar Button 项之间的间距。

func addLeftBarButtonItems() {

    let btn1 = UIButton(type: UIButton.ButtonType.custom) as UIButton
    let list_icon = UIImage(named: "list") as UIImage?
    btn1.setImage(list_icon, for: UIControl.State.normal)
    let item1 = UIBarButtonItem()
    item1.customView = btn1

    let btn2 = UIButton()
    btn2.setTitle("Notification", for: .normal)
    btn2.setTitleColor(UIColor.black, for: .normal)
    let item2 = UIBarButtonItem()
    item2.customView = btn2

    let btn3 = UIButton(type: UIButton.ButtonType.custom) as UIButton
    let redbadge = UIImage(named: "red_badge") as UIImage?
    btn3.setBackgroundImage(redbadge, for: UIControl.State.normal)
    btn3.setTitle("10", for: .normal)
    btn3.titleLabel?.font = .systemFont(ofSize:10)
    btn3.setTitleColor(UIColor.black, for: .normal)
    let item3 = UIBarButtonItem()
    item3.customView = btn3

    let space = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
    space.width = -8

    self.navigationItem.leftBarButtonItems = [ item1, item2 , space ,item3]
}

如何减少/增加通知标题和徽章图标和 .固定空间似乎不起作用。

Answer 1

间距的负值不起作用。然而，正值确实如此。