标签栏的选择指示器不起作用

Question

您好，我是 iOS 新手。

我已经通过 Storyboard 实现了一个 tabBarController 以及 4 个 tabBar 项。现在，我需要自定义标签栏，如下图所示。我已经为标签栏设置了背景。

 + (UIImage *)imageFromColor:(UIColor *)color {
     CGRect rect = CGRectMake(0, 0, 1, 1);
     UIGraphicsBeginImageContext(rect.size);
     CGContextRef context = UIGraphicsGetCurrentContext();
     CGContextSetFillColorWithColor(context, [color CGColor]);
     CGContextFillRect(context, rect);
     UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
     UIGraphicsEndImageContext();
     return image;
 }


 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

      [[UITabBar appearance] setTintColor:[UIColor whiteColor]];

      [[UITabBar appearance] setBackgroundImage:[AppDelegate imageFromColor:[UIColor blackColor]]];

      return YES;
   }

标签栏的背景设置没有任何问题。

当我尝试为选定的标签栏项目设置颜色时，它不起作用。不知道为什么？

[[UITabBar appearance]setSelectionIndicatorImage:[AppDelegate imageFromColor:[UIColor orangeColor]]];

我需要像这样自定义我的标签栏：

我该怎么做？

Answer 1

首先你应该记住UITabBar的配置应该在AppDelegate.m:

您应该添加[[UITabBar appearance]setSelectionIndicatorImage:[AppDelegate imageFromColor:[UIColor orangeColor]]]; AppDelegate.m 在applicationdidFinishLaunchingWithOptions 方法中。

其次，在您的情况下，您应该提供标签栏项目选中状态示例：

   UITabBarController *tabBarController = (UITabBarController   *)self.window.rootViewController;
   UITabBar *tabBar = tabBarController.tabBar;
   UITabBarItem *tabBarItem1 = [tabBar.items objectAtIndex:0];

   //We set title
   tabBarItem1.title = @"Home";

   //We set highlighted state
   [tabBarItem1 setFinishedSelectedImage:[UIImage imageNamed:@"home_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"home.png"]];

   // Change the tab bar background
   UIImage* tabBarBackground = [UIImage imageNamed:@"tabbar.png"];
   [[UITabBar appearance] setBackgroundImage:tabBarBackground];
   // Tab bar active background
   [[UITabBar appearance] setSelectionIndicatorImage:[UIImage imageNamed:@"tabbar_selected.png"]];

Answer 2

将选择指示器图像直接设置到标签栏以及外观对我有用。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

     UITabBarController *tabBarContr = (UITabBarController *)self.window.rootViewController;
    [[UITabBar appearance] setSelectionIndicatorImage:[UIImage imageNamed:@"tab_bar_selection_indicator.png"]];

    // iOS7 hack: to make selectionIndicatorImage appear on the selected tab on the first app run
    [[tabBarContr tabBar] setSelectionIndicatorImage:[UIImage imageNamed:@"tab_bar_selection_indicator.png"]];

    return YES;
}