iphone - 标签栏项目上的角标(Badge)未显示

Question

在我的应用程序中，我的 tabBar 项的标记值设置在 AppDelegate.m ，如下:

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    ...
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    UITabBarController *tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarController"]; 
    [[tabBarController.tabBar.items objectAtIndex:4] setBadgeValue:@"1"];
    ...
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    ...
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    UITabBarController *tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarController"]; 
    [[tabBarController.tabBar.items objectAtIndex:4] setBadgeValue:@"2"];
    ...
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    ...
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
    UITabBarController *tabBarController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarController"]; 
    [[tabBarController.tabBar.items objectAtIndex:4] setBadgeValue:@"3"];
    ...
}

问题是:角标(Badge)值始终为“1”。为什么在 applicationWillEnterForeground: 中都设置了角标(Badge)值和 applicationDidBecomeActive:永远不会出现？如果我没有在 application: didFinishLaunchingWithOptions: 中设置角标(Badge)值，那里没有显示角标(Badge)。

Answer 1

您需要阅读 UIApplicationDelegate 协议(protocol)以及各种状态转换。 applicationDidBecomeActive 转换不会在启动时发生，只有在手机中发生一组状态更改时才会发生。