ios - NSUserActivity : 使用循环索引多个 NSUserActivity

Question

我想索引多个NSUserActivities相同类型的。下面给出了相同的代码：

-(void)createActivityForEachCity:(NSNotification *)notification
{
    NSArray *nameList = @[@"name1",@"name2",@"name3",@"name4"];
    if (nameList)
    {
        for (NSString *name in nameList)
        {
            [self createIndexActivityForName:name];
        }
    }
}

-(void)createIndexActivityForName:(NSString*)name
{
    NSUserActivity *activity = [[NSUserActivity alloc]initWithActivityType:@"spotlightsearchactivity"];
    NSDictionary *activityUserInfo = @{@"name":name};
    activity.userInfo = activityUserInfo;
    activity.title = [NSString stringWithFormat:@"You Searched for %@",name];
    activity.eligibleForHandoff = NO;
    activity.eligibleForSearch = YES;
    activity.eligibleForPublicIndexing = YES;
    self.userActivity = activity;
    [activity becomeCurrent];
}

从上面的代码中，name1, name2, name3 and name4必须创建 NSUserActivities 。但我得到的是，NSUseractivity 被覆盖，即，只有name4被索引。

代码中缺少什么？