ios8设置application badge value

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