iOS tabbarn/navigationBar字体/背景颜色

一. tabbar背景颜色/字体颜色

• 改变tabbar的选中的item的字体颜色，和未选中的item的字体颜色：

  self.tabbar.tintColor = [UIColor redColor];
  

   self.tabbar.unselectedItemTintColor = [UIColor yellowColor];
  

• 改变tabbar的背景颜色，方法1:

  self.tabBar.barTintColor = .blue
  self.tabBar.backgroundColor = .blue
  

• 改变tabbar的背景颜色，方法2:

  self.tabBar.backgroundImage = UIImage.withColor(.red)
  self.tabBar.backgroundColor = .blue
  

• 改变tabbar的背景颜色，方法3:

   if #available(iOS 13, *) {
      let appearance = self.tabBar.standardAppearance.copy()
      //appearance.shadowImage = UIImage.withColor(.yellow)///设置阴影
      //appearance.shadowColor = .yellow///设置阴影
      appearance.backgroundImage = UIImage.withColor(.yellow)
      appearance.backgroundColor = .yellow
      self.tabBar.standardAppearance = appearance
      if #available(iOS 15.0, *) {
        ///用这个方法的，这个一定要加，否则15.0系统下会出问题，一滑动tabbar就变透明!!!
         self.tabBar.scrollEdgeAppearance = appearance
        } else { }
      }
  

• 总结：

  • 方法1或者方法2中的属性设置，一定要成对出现！！！如果只设置backgroundImage/barTintColor或者只设置backgroundColor，一滑动tabor就会变透明
  • 使用方法3:
    • 如果不适配ios 15.0，也就是不加上self.tabBar.scrollEdgeAppearance = appearance，也会出现一滑动控制器，tabbar变透明

• 不得不骂一句，操蛋的苹果，改个背景颜色，要几个属性组合使用，不同的组合适配不同的系统版本，一个不小心就是掉坑里了！！！

二. navigationBar背景颜色/字体颜色

• 改navigationBar的字体颜色：

  let appearance = UINavigationBarAppearance()
  appearance.backgroundColor = bgcolor
  appearance.shadowColor = .clear///下划线颜色
  appearance.titleTextAttributes = [.foregroundColor:titleColor,.font:UIFont.systemFont(ofSize: 18)]
  self.navigationController?.navigationBar.standardAppearance = appearance
  self.navigationController?.navigationBar.scrollEdgeAppearance = appearance
  

• 关于tabbar和navigationBar的scrollEdgeAppearance的区别：
  • 1. 两个appearance都继承同一个类UIBarAppearance。而UIBarAppearance四个决定背景颜色的属性和阴影的属性就是：

    /// A color to use for the bar background. This color is composited over backgroundEffects.
    @NSCopying open var backgroundColor: UIColor?
    /// An image to use for the bar background. This image is composited over the backgroundColor, and resized per the backgroundImageContentMode.
    open var backgroundImage: UIImage?
    /// The content mode to use when rendering the backgroundImage. Defaults to UIViewContentModeScaleToFill. UIViewContentModeRedraw will be reinterpreted as UIViewContentModeScaleToFill.
    open var backgroundImageContentMode: UIView.ContentMode
    /// A color to use for the shadow. Its specific behavior depends on the value of  shadowImage. If shadowImage is nil, then the shadowColor is used to color the bar's default shadow; a nil or clearColor shadowColor will result in no shadow. If shadowImage is a template image, then the shadowColor is used to tint the image; a nil or clearColor shadowColor will also result in no shadow. If the shadowImage is not a template image, then it will be rendered regardless of the value of shadowColor.
    @NSCopying open var shadowColor: UIColor?
    /// Use an image for the shadow. See shadowColor for how they interact.
    open var shadowImage: UIImage?
    

  • 2. tabar的scrollEdgeAppearance是15.0后有的
       而navigationBar的scrollEdgeAppearance是13.0后有的:

    /// Describes the appearance attributes for the tabBar to use when an observable scroll view is scrolled to the bottom. If not set, standardAppearance will be used instead.
    @available(iOS 15.0, *)
    @NSCopying open var scrollEdgeAppearance: UITabBarAppearance?
    @available(iOS 13.0, *)
    @NSCopying open var scrollEdgeAppearance: UINavigationBarAppearance? 
    

  • 3. 如果采用赋值standardAppearance改变背景颜色，无论tabbar和还是navigationBar都要设置scrollEdgeAppearance，否则就会出现滑动变透明的问题。

三。.translucent 属性干了什么

• 是YES的时候，tabbar的视图层级是
  UITabBar-->UIBarBackground-->UIVisualEffectView-->UIVisualEffectBackdropView-->UIVisualEffectSubview-->UIVisualEffectSubview (决定tabbar颜色的视图)
• 是NO的时候，tabbar的视图层级是
  UITabBar-->UIBarBackground-->UIImageView (决定tabbar颜色的视图)
• YES还是NO，从颜色效果上，我没看出区别
• translucent = NO 对UICollectionView截屏的影响，具体见第十一条
• 使用方法1和方法2的时候，视图层级和self.tabbar.translucent = NO一摸一样，都是3层
• 改变tabbar的背景颜色，又看到下面这个方法

       UIView *color_view = [[UIView alloc]initWithFrame:self.tabBar.bounds];
       color_view.backgroundColor = [UIColor redColor];
       [self.tabBar insertSubview:color_view atIndex:0];
  

  这个方法只是改变tabbar部分的背景颜色，tabbar到底部的安全区safeArea有一条是改变不了的。比如使用上面的方法设置tabbar为redcolor，tabbar下面的安全区有一条留白。