UINavigationBar 在 AppDelegate.swift 中设置自定义阴影 [英] UINavigationBar set custom shadow in AppDelegate.swift

问题描述

我想为整个应用程序在 UINavigationBar 的底部设置一些阴影.这是我尝试过但不起作用的方法:

I want to set some shadow to the bottom of my UINavigationBar for the whole application. Here is what I've tried but it doesn't work:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    UINavigationBar.appearance().layer.shadowOffset = CGSizeMake(0, 3)
    UINavigationBar.appearance().layer.shadowRadius = 3.0
    UINavigationBar.appearance().layer.shadowColor = UIColor.yellowColor().CGColor
    UINavigationBar.appearance().layer.shadowOpacity = 0.7
}

请告诉我我该怎么做?

更新:通过从 UINavigationController 继承子类解决

UPDATE: Solved by subclassing from UINavigationController

import UIKit

class ShadowUINavigationController: UINavigationController {

    override func viewWillAppear(animated: Bool) {
        let darkColor: CGColorRef = UIColor(hex: 0x212121).CGColor
        let lightColor: CGColorRef = UIColor.clearColor().CGColor
        let navigationBarBottom: CGFloat = self.navigationBar.frame.origin.y + self.navigationBar.frame.size.height + 20
        println(self.navigationBar.frame.origin.y)
        println(self.navigationBar.frame.size.height)
        println(navigationBarBottom)

        let newShadow: CAGradientLayer = CAGradientLayer()
        newShadow.frame = CGRectMake(0, navigationBarBottom, self.view.frame.size.width, 1)
        newShadow.colors = [darkColor, lightColor]
        self.view.layer.addSublayer(newShadow)
        super.viewWillAppear(animated)
    }
}

推荐答案

一个更好的解决方案是仍然使用外观并且不需要您对 UINavigationBar 进行子类化并向每个导航控制器添加代码:

A better solution by still using appearance and that does not require you to subclass the UINavigationBar and adding code to each navigation controller, would be:

扩展 UINavigationBar

Extend the UINavigationBar

extension UINavigationBar {

  var castShadow : String {
    get { return "anything fake" }
    set {
        self.layer.shadowOffset = CGSizeMake(0, 3)
        self.layer.shadowRadius = 3.0
        self.layer.shadowColor = UIColor.yellowColor().CGColor
        self.layer.shadowOpacity = 0.7

    }
  }

}

并添加应用范围的外观规则(例如在 appdelegate "didFinishLaunchingWithOptions" 中)

And add an app wide appearance rule (inside appdelegate "didFinishLaunchingWithOptions" for example)

UINavigationBar.appearance().castShadow = ""

这篇关于UINavigationBar 在 AppDelegate.swift 中设置自定义阴影的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！