简单实现导航栏透明

导航栏的颜色可以统一设置

let navigationBar = UINavigationBar.appearance()
//是否透明
navigationBar.isTranslucent = false
//导航栏颜色
navigationBar.barTintColor = UIColor.red
//导航栏文字颜色
navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]

当我们要在某个控制器实现导航栏的透明效果时:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: UIBarMetrics.default)
    //去掉底部线
    self.navigationController?.navigationBar.shadowImage = UIImage()
    //是否透明
    self.navigationController?.navigationBar.isTranslucent = true
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    self.navigationController?.navigationBar.setBackgroundImage(nil, for: UIBarMetrics.default)
    self.navigationController?.navigationBar.shadowImage = nil
    self.navigationController?.navigationBar.isTranslucent = false
}

需要注意的是UINavigationBar的isTranslucent属性

• 当isTranslucent为true时,往控制器的View里面添加子view的时候,如果要从导航栏下面开始,那么子view的y要从64开始.
• 当isTranslucent为false时,往控制器的View里面添加子view的时候,如果要从导航栏下面开始,那么子view的y要从0开始.