Objective-C获取应用是否允许消息通知的方法

用户可能对应用设置是否允许通知，OC的API中iOS8之前和之后是两个方法：

- (BOOL)isAllowedNotification {

if ([[UIDevice currentDevice].systemVersion doubleValue] < 8.0) {

UIRemoteNotificationType type = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];

if(UIRemoteNotificationTypeNone != type)

return YES;

}else{

UIUserNotificationSettings *setting = [[UIApplication sharedApplication] currentUserNotificationSettings];

if (UIUserNotificationTypeNone != setting.types) {

return YES;

}

}

return NO;

}