设置间距

let space = UIBarButtonItem.init(barButtonSystemItem: .fixedSpace, target: nil, action: nil)

space.width = 20

添加间距到item

navigationItem.rightBarButtonItems = [space,OtherItem]

背景颜色设置

navigationController?.navigationBar.barTintColor = .red

navigationController?.navigationBar.barStyle = .blackTranslucent

Item颜色及中间title颜色

navigationController?.navigationBar.tintColor = .white

navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: .red]