在IOS7中设置applicationIconBadgeNumber不会有什么问题，但是直接在IOS8中设置applicationIconBadgeNumber会报错。因为在IOS8中要想设置applicationIconBadgeNumber，需要用户的授权，在IOS8中，需要加上下面的代码：
UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge categories:nil];
[[UIApplication sharedApplication] registerUserNotificationSettings:settings];
但是这两句如果是在IOS7的系统中运行的话就会报错，所以需要先判断IOS的版本，完整代码如下：
float version = [[[UIDevice currentDevice] systemVersion] floatValue]; if (version >= 8.0) { UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge categories:nil]; [[UIApplication sharedApplication] registerUserNotificationSettings:settings]; }
如果是注册消息推送的话，需要这样写：
float version = [[[UIDevice currentDevice] systemVersion] floatValue]; if (version >= 8.0) { UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge categories:nil]; [[UIApplication sharedApplication] registerUserNotificationSettings:settings]; [application registerForRemoteNotifications]; }
iOS-解决iOS8及以上设置applicationIconBadgeNumber报错的问题
原文：http://www.cnblogs.com/yongdaimi/p/6040711.html