在ios8中，直接设置application badge value会出错
[[UIApplication sharedApplication] setApplicationIconBadgeNumber:count];
曝出”Attempting to badge the application icon but haven't received permission from the user to badge the application“的错误。
原因是因为在ios8中，设置应用的application badge value需要得到用户的许可。使用如下方法咨询用户是否许可应用设置application badge value
UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge categories:nil];
[[UIApplication sharedApplication] registerUserNotificationSettings:settings];
程序运行时，会弹出提示框给用户
之后再通过
[[UIApplication sharedApplication] setApplicationIconBadgeNumber:count];
设置application badge value