How to set a badge value on a UITabBarController item_how to set badge in vivo android phone-优快云博客

本文介绍如何在iOS应用中为UITabBar项设置Badge值。Badge值是显示在Tab栏图标上方的小红标记，可以用来提示用户有关更新或通知的信息。文章提供了设置不同样式Badge值的方法，并解释了如何通过UIViewController或UINavigationController来访问并修改这些值。

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这里写图片描述
Each view controller has access to a UITabBarItem. This is only displayed if the current view controller is part of a UITabBarController. A UITabBarItem has a badge value which is that little red mark above icon and name to the tab bar item itself (as shown in the screenshot above: LIVE is currently the badgeValue of the tab bar item).

Here’s how you can set the badge value:

// set the tab bar value (any NSString will work):
self.tabBarItem.badgeValue = @”LIVE”;

// make it disappear again
self.tabBarItem.badgeValue = nil;

// set it to a little red circle (no value, just an empty string)
self.tabBarItem.badgeValue = @”“;
This approach will work if you have direct access to the class in the view controller. More commonly though you’ll have your own class embedded in a UINavigationController, in which case its tab bar item (and title) is shown on that tab.

In which case you can access the tab bar item like this:

// set badge value on your own nav controller
self.navigationController.tabBarItem.badgeValue = @”LIVE”;
https://developer.apple.com/library/ios/documentation/uikit/reference/UITabBarItem_Class/Reference/Reference.html

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